Exercices corriges Amateur-Radio-1985-03 pdf
AMATEUR RADIO: UK Ham Radio and Two-Way radio periodical
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MARCH 1985 99p
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For all two-way radio enthusiasts
teoeese"eeet9eeete`eige sae eiee lee"
On test: MIVIT144/28R 2m transverter
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es
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1503 Metal Chassé Supports Pair
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1101310
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160: 1.95
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140: 2.15
THICK FILM RESISTOR UNITS
3500 Thorn ( 5Pin Connection) video
1.70
4080 Thorn (4Pin Connection)
1.90
725/731 Pye 16 Pin Connection)
2.20
713 Pye ( 6Pin Connection)
2.20
FUSES
20mm
SOMA
10 for 10p 250MA
315MA A/S 10 for 50p 750MA
500MA
10 for 50p 7A
lA
10 for 50p 10A
25A
10 for 1.00 2M
315A
10 for 1.00 50A
1.I" 10 for 65p 10 for 650 10 for 50p 10 for 50p 10 for 50p 10 for 50p
Thorn Mains TX 3000/3500 Thorn Mains TX 8000/8500 Thorn SOFT 80)2/8500 Thorn Scan TX 354/350 Thorn EHT TX 3003/3500 Thorn LOFT 9600 Thorn LOFT 1615 Thorn LOFT 1590/91
Thorn LOFT 8000 Thorn LOPT 8500 Thorn LOFT TX9 Pye LOFT 713 Pye LOFT 725 Pye LOFT 731 Fhilips LOFT G9 Fhilips LOFT 611 GEC LOFT 3113
Diode Split LOFT AT2076/35 Sanyo LOFT AM-WM-21 Sanyo LOFT AM-WM-4 Philips LOFT 68 Sanyo LOFT ( CW211 4-2751.44700 ITT LOFT CVC5-9 ITT LOFT CVC3) ITT LOFT CVC45 Baird 8750 Baird 8752 Korting AZ9100 Karting 892-170 Korting AZ2101 Korting A73103 Kortmg ZTR1001 Siemens V1155 Siemens V1823 Zanussi BS2222 Zanussi 852213 Sabra FR0357 Salora FR0029
7.50 10.00
3.50 _6.00 6.00 12.00
7.25 7.25
9.10 9.80 9.85 10.00 9.85 1618 8.80 13.75 7.40 14.75
6.75 7.30 7.80 5.00 9.60 8.75 9.75 10.25 10.25 10.25 10.25 10.25 1025 10.25 11.75 11.75 10.3 10.3 10.25 10.25
300 Mixed Resistors 300 Mixed Capacitors 150 Mixed Electrolytics 100 W/W Resistors
20 Mixed Cony Pots 40 Mixed Pots
20 Mixed Sliders
1.50 10 Spark Gaps1.00
1.50 10-16 pin Dui' IC Socket
90p
2.00 20 Assorted TV Knobs
1.00
1.00 10-16 pin Dui' to Dil IC Socket 90p
1 00 100 Mixed Diodes
1.00
1:50 50 Mixed Mica Washers
65p
300 Mixed Resistors & Capacitors 1.50
10-16 in Dil to Dil IC Socket 1.00
40 Mixed Presets
60 13 50 Electrolytics & 50 Capacitors 1.00
20 Mixed VDR & Thermistors 1.00 50 Mixed Poly Capacitors
1.00
20 Mixed Ferrite Cores
50P 30 Mixed Neons & Bulbs
1.00
100 Mixed Ceramic Discs
100
20 Mixed Valve Bases
1.00 IFF116273
AC128 AC131 AC138 AC141K AC142K AC153 AC176
AACC117268KK/ AC188 AD142 ADI43 AD149 AD161 AD162 AD263 AF127 AF139 AF239 BC107 BC108 BC109
39 BC172 40 BC1148 40 BC177 39 BC182LB X BC183L 39 BC184L 33 BC187
93 BBCC223018 X 8C212L 1.18 BC213L 1.08 BC37 98 13C2388 32 BC238L 32 BC256A 1.05 BC251 45 BC252A X BC294 41 BC301 15 BC333 15 BC337 15 BC308
9 BC559 22 BC595 24 BCX33 12 BCX34 12 BD115 13 1313131 14 50132
159 5800113339 9 B0140
12 130144 12 130150 8 80163
I 80201 15 80203 I EID204 20 BD/22 3 80225 32 13032 3 BC1133 1 80134
80237
8 BF179
8 BF180 22 8F181 11 BF184
49 13F1135 XI BF194 46 BF195
5X389
BBFF 1916 97 BF198
1.70 BF199
50 8F223
98 13E224 74 BF233
71 BF240
99 BF241
48 13F255 52 BF256S 50 BF257 60 BF259 60 BF271 55 BF274
24 BFRe1
23 NKT276
29 8R811
29 NKT453
32 BFR87
25 OT112
33 BFR913
1.74 OT121
30 BFF191 X BFT42
2.08 R1038 X R1D39
30 BFT43
30 R20088
16 BFX38
40 R20108
16 BFY50
X R2030
, 1 16 ,,BFrYi ,512 34 324 3R 9202655
19 EIRC116 1.50 9322
15 BRC1693 1.43 R2443
18 BU105
1.00 RCA16446
19 BU126 20 BU207
1.10 RCA16599 1.05 RCA16600
9 13U208
1.15 RCA16799
21 BU2013A 1.15 RCA15900
10 BU326A 1.30 RCA16802
20 B11407
1.70 S1299
28 13U408
2.76 S28003
28 BUS(0)
2.30 56080A/13
25 BU526
2.46 16050V
11 BU807
2.94 16052V
20 1.65 1.92
2.s0o8
80 1.40 1.10
70
1.s3o0 so zs
30 1.25 1.40 1.13 1.42 1.31 2.25 1.25 3.50 1.30 1.30
BC115 BC117 BBCC112256
BC139 BC141
BBCC114423 BC147 BC148 BC149 BC153 BC154OR BC154YL BBCC115587
BC159 BC171
16 BC309 21 BC327 7X3 9BCC333278
1 130138 1 00241 11 1B300224748A
27 6C338
1 13D336
34 BC347
130433
X31 B BC4C 35944 1305139042 37
12 BC455
8D589
12 BC456 12 13C460
1 80677G 40 80107
16 BC463
22 80708
16 BC546
8 BOX10
16 BC547
12 BDY20
1122 BBCC554498
128 B8F01Y3673
15 BC557 9 BC558
10 BF153 10 BF154
65 13F337 59 BF338 8815 8BFF336525
68 BF391 71 BF394 1.8230 B13FF442232
1.20 BF450 1.35 BF4S3
95 BF458 95 13F459 93 8F461 1.09 13F556B 2909 BBFF659946
20 BF757 25 BFR52
3294 Ccilli2292,
9 9 1T59010103V.415 .25
42 5001 EEE9953030083,6
5n4 1159005534VV
11..3000
16 ME0404
25 19039V 1.10
10 TIC49(
50
4573 MMEE06401022
1100 TTIICC4I6O6C
4480
43 MJ2501 2.36 TIP29
42
53 MJ3001 2.21 TIP30
42
37 MJE182
47 TIP31
35
40 MJE340
50 TIP32
43
59 MJE520
50 TIP33
61
35 MJE2955 1.40 TIP41
42
165 NMKJET2X4615VV 1508 TTIIPP41210
45 61
62 NKT2416
8 TIS91
25
31 NKT241Y
8 ZTX550
30
INTEGRATED CIRCUITS
BRC1330 59133564
1.40 SN76013ND 1.00 SN76323N
SRC/M/208 BRC/M/300
1.00 SN76033N 1.00 5N76115
CA3060 LM1303P
M1231 B
ML237B M1.23913
1.58 SN76131N 1.48 SN76226N
2.20 SN76127N
2.00 SN76530P 2.86 SN76622N
MC1327AP
MCI358P MC1455P MC14516BCP SAA1025
1.25 SN76660N
130 SN76666N Illp SN76744 Cap TA71I7P 7.20 TA7109AP
SAA1124
4.50 TAA611
54A5010 SL4324
6.00 1541208 1.80 TBAI20C
SL1430 SN15846N SN741Z3N SN74154N
2.50 TBA120C0 60p 1541205 65p TE3A1201.1 1.40 154395
SN76001 N SN76110N
1.40 1544800 1.14 TBASIO
TBA530
1.80 1134540
1.80 TBA55011
2.00 TBA560C
2.00 1134641
1.58 194651
1.25 1847204
1.00 1134750
1.30 TBA800
1.00 1848105 80p TBA810AS
75p 1134920
1.92 TBA950 1.00 1841440
2.80 TCA27DSA
1.40 TCA270C
1.20 1134270130
1.20 TDA11:04A
TOP 10410351
TOP 1041037
1t.o0o0
10411705 TDA1203
1.40 TDA1170
1.90 1041327
Thorn 8/865 ex equip panels
untested
PSU
2.88
FT13
3.75
Decoder
4.00
Thorn 9K ex equip panels
untested PSU
12.00
Decoder
5.00
Thorn 966 ex equip panel
untested
Decoder
5.75
Thorn 3/315 ex equip panels
untested
PSU
3.75
LIB
3.75
Video
2.50
Chroma
2.00
FTB
2.75
IF
1.75
Cony 3K
3.00
Cony. 31(5
3.75
Autovox Decoder FG/01 new
boxed
500
Thom 4000 Convergence panel
ex-factory
3.75
112.0: TTD0AA22t11120
112
150
TDA25U TDA2530 TDA2540
221. 2.:401;3 TTTTSD9AAAA2222655511111: 4
1.62 TDA2640
100 TDA2690A
1.00 TDA3560
2.01 1049503
1.95 TCEP1C0
1.92
1.05 1.05 1.05 4.00
TEA1009 MC14426P MC14429P MCI4514 UA758PC
3.50 UU4LN19421645
2.72 utAnIset 1.50 UPC1365C
2.42 SC9488P
3.90 SC9511P
2.53 SW153
2.80 2.10 2.10 2.61 3.50 3.50 3.00 1.96 1.95 2.90 1.50 6.00 2.90 3.48 1.95 4.80 4.50 5.00 2.50 2.66 1.30 125 5.75 1.40 1.40 2.50
Thorn 4ow PSU panel ou
factory
2.50
Thom 3K5 beam limiter board
new
1.75
Thorn 3K5 PSU bottom board
PC206 new
2.75
Thorn 3K5 IF panel new 3.00
Thorn 3/3K5 EHT & scan TX +
R200813 on alum chassis ex-
equip
1.80
Thom 8/8K5 damaged FTB for
spares
1.25
Thorn 8/81(5 damaged decoder
for spares
2.25
UHF TV Aenal for portable Indoor Aerial Parabolic Type Reflector
to Help Combat Ghosting Problems Line Connectors
50p Coax Plugs Band Change Switch Assy, Pye 725
2.50 Rush Mounting IV/FM Diplexer Xp Switched Flush Fitting Aenal Outlet
10 for 1.65 40p
1.00 1.00
Pye 78-.161
50p
Pye 147+260
50p
Thorn 56+1K+47+12
1.24
Thorn 50+40+ IK5 60p
Thorn 128+16+ 1K7+
116+462+126
50p
Thorn 120+72+300
50p
RBM 250+14+ 58
ITV161)
63p
Pye 395+15+45 17131
90p
Philips 2R2+682 90p
Philips 479
52p
Thorn 350+20+148+
165+317
1.40
Thorn 6-1-100 92p
Thorn 3000 Metal 1.45 Thorn 8/8500 Plastic
1.45
EHT TRAYS
Thorn 3030
5.50
Thorn 8000
3.50
Thorn 8500
6.00
Thorn 9000
7.90
Thorn %CO
6.00
Thorn 900/950
1.50
Pye 713 5lead Pye 725
Decca Bradford Baird 8750 Korting 439103 Philips 68 ( 520) Philips G8 ( 5501 Universal
5.97 6.35
5.00 7.10 7.10 6.50 6.50 5.00
MULTISECTION CAPACITORS
100 + 150 + 150
203+200 + 100
220,41
350V 50p
350V 55p
350V 65p 203+200 + 75+25
200+150+50 350V 60p
350V 60p
200+200+100
50 - 50 + 8 XOV 55p
325V 54p 103 + 50+100 350V 55p
32 + 32 + 16 275V 52p 100 + 150 + 50 350V 55p
200 , 203+100+32
2500+2500 ( Thorn 8KI
350V 70p
63V 1.20
103+50+150 350V 58p 150-150-100
400 + 403
200V 72p
303V 1.80
32 +32 +16 350V 52p 203 + 47
250V 65p
200 * 32 + 300 + 100
5C0 + 500 175V
225,25
350V 70p Thorn TX9
1.00
350V 50p 175 , 100+100 350V
203+200+100
Thorn 315
2.25
350V 70p 403 4COV Thorn 9K 2.50
200,100
325V 65p 470 250V
200+100+100+50
Philips 611
1.50
393V 60p
CAN TYPES
0.2MF 250V
50p
2MF 250V
50p
nmF 275V
50p
SOMF 275V
50p
100MF 150V
65p
1COMF 250V
70p
1COMF 450V
75p
220MF 400V Thorn 9K
1.30 220MF 450V Thorn 4K
1.30
400MF 350V Thorn 8K
1.00
type800MF 250V Print
250V
171001p)
1250MF 40V
50p
1250MF 50V
50p
1500MF 70V Thorn 3K
1.00
1500MF 103V
1.05
2000MF 30V
50p
220MF 40V Thorn 4K
95p
2203MF 63V Philips 69
125
2500MF 35V
65p
2500A1F 40V
65p
3000MF 30V
65p
3300MF I6V
50p
3300MF 25V
60p
4700MF 16V
72p
4703MF 40V
75p
Thorn/Decca/GEC On/Off Switch. Push to
make
75p
Philips 611 On/Off Switch. Push to make 75p
ITT CVC8 On/Off Switch
65p
In CVC9 On/C)ff Switch , Relay
5°P
Philips 68 On/Off Switch
75p
Thorn 3/3500 Al Switch Thorn 454 Al Switch
50P 50P
Karting Shift Pot 5011
65p
2SA Push to make on/off switch
15p
DIODES
AA112
Bp N4003
4p
AA119
Op
Sp
AA143
Op
Sp
BBAA111554
Bp N4006
5p
B13103
ap N4007
62pp
BBBR11005313
1 3,4NN4 41 14489
6p
131106 5911111169 1B3Y1112270 81151 650 ,, By Y210848 BY206
BY207 BBYY21°183 /8133 BY225 9 By Y22297,
52p 1.50 2 21.. .805026
N4742A N525413 NNN555434040190
1.00 126p9 25p 16p
N5402 N N554440:1 6 S025
18lip S131
j3IIP SmsKR1 E681558/4o2 Xp MCR106/1
BBpp 14p 12p 12p 14p 12p 16p 16p
Bp Bp Bp
?ig35p
35p
B5Y1X92(25/54/0504
3 32i2tP, p y 2MN,C2474
11.1500p
BYX71 /350
80p Y969
75p
82V15 Cl2R 1 BNZ6V015 C24R IN40132
1.16 1.81, p6p
2X150
12p
5p
mOsmAyc9cRm,1151 0c66/8 13.015.00p0
I1 INN42070 N444 p TD31 F81:10nH80 2.
4p 10398366
3.00
ANGUS McKENZIE
TESTS
Microwave Modules has been established for well over adecade as aBritish manufacturer marketing VHF and UHF converters, transverters and solid-state linears. In the past, their transverters have been built into simple diecast boxes, originally having no external finish, but more recently supplied in a utilitarian black finish, sometimes in black crackle. This has improved the presentation but the basic circuitry in many of their models has remained the same for years and years.
Their earlier transverters were supplied with BNC sockets for inputs and outputs, but more recently they have been fitted with S0239s for the 2m versions, although BNCs and N- types can be supplied to special order. They
have always used locking 270 degree five pin DIN sockets for 13V dc and PTT interconnections, and these are retained in this new model, pin- 1 being PTT override, pin- 3negative earth and pin- 5 13V positive. On some models pins 2and 4 were used for external switching of special repeater shifts but now repeater switching is by a switch on the front of the rig.
MICROWAVE MODULES MMT144/28R
2m TRANSVERTER
Circuitry
Previously, their 2m transverter from 28MHz did not incorporate repeater shift, and the output power was rated at 10W although 20W could be obtained
quite easily with optimum adjustment around the PA unit. The transmit performance was always reasonably good but it was in the receiver that some
problems had been encountered because of rather old circuit designs. The new model incorporates an NE411 dual- gate GaAsFET feeding into an STE M14 high level diode ring mixer with optimised matching.
The 116M Hz crystal local oscillator has
its output fed through the crystal itself to improve purity and to reject sideband noise rather better. This output is
amplified by a JFET having a bandpass filter around it, which then supplies the mixer injection. The output from the receive mixer feeds into a low gain output stage at 28MHz, also employing a
JFET. The receive configuration is thus
completely new, whereas the transmit
strip uses their older double FET push/pull mixer and low level amplification stages. The 'final driver stage employs a0.5W driver instead of a100mW device, but is run at a maximum output level of around 50mW for improved intermodulation performance.
The design of the PA stage is totally
new, employing a driver type 2N6082, feeding the PA itself, atype SD1278 50W device, which is reasonably linear at the maximum 25W output level designed into the new transverter.
The PA output feeds through three matching circuits, which include traps, and then through to a pin diode switch.
An ALC loop is fed right from the output, the sensed level also being fed to a bar
graph display controlled by a regulated
dc supply. This display incorporates 10 indicators, the highest level coming on at around 23W. The ALC also feeds back to a diode attenuator immediately before the mixer and apreset can be set to give the required maximum output level.
The 28MHz input drive is sensed by a
lightly coupled RF circuit and amplified with an op- amp IC, providing much more
sensitivity for RF switching than was available in earlier transverters. The input drive is fed through apreset which can adjust maximum drive level for full output from 300mW down to around 250µW. This allows the transverter to be
used with almost any HF rig on the market fitted with a transverter drive
facility, and it can thus be fed directly from the latest Yaesu and lcom rigs which have transverter drives well below 1mW.
All the low level stages are in Class A, again to improve linearity and the local oscillator feeds into the mixer, again
with aJFET filtered buffer. The PA bias supply is now regulated from avery low source impedance and this again contri-
butes to improved PA performance. The PTT switching is now much faster
than before, high value capacitors being avoided so as to allow AMTOR to be used
with this transverter. The RF sensing circuitry is vastly improved, and apot on the front panel is provided to adjust the
Tx hold time from very short indeed (around 15mS) to around 1.5 seconds. Other controls on the front panel include an on/off switch and asimplex/repeater/ reverse repeater miniature toggle which allows repeater operation with HF rigs not having dual VFOs for Tx and Rx.
A dc fuse is provided on the back panel and the 13.8V input is also reverse diode protected. Whilst two S0239 sockets are provided for 28MHz input and output, just a single 144MHz S0239 socket is now fitted, for the manufacturers feel that
anyone wanting aseparate socket could fit it for themselves. Apparently market surveys indicated that only avery small proportion of users actually use the independent receive socket of the old model. 1feel it is apity that this has been omitted, but whilst I used to use it, frankly, it is fairly superfluous unless you
have a special requirement.
Styling
As will be seen from the photograph, the styling is totally different from any previous MM product, and I think it shows avery considerable improvement. I would have preferred more robust switches but, presumably, costs had to be kept down. Ifeel that provision of the input drive preset is a very significant advantage, but I also found that one could drive the rig at least 10dB into ALC
MARCH 1985
please mention AMATEUR RADIO when replying to any advertisement
21
A--iteitte
6 Letters Your opinions on topics of interest
8 Straight and Level All the latest news, comment and developments on the amateur radio scene
47 Back to basics This month Bill Mantovani G4ZVB explains the theory behind transmitters
t-vcc
Editor: Jim Chalmers Editorial Assistant: Anita Ley Advertisement Manager Anne Haden Subscriptions: 01-684 3157 Accounts: Clare Brinkman Publisher: Peter Williams General Manager Alan Golbourn On sale: Fourth Thursday of the month preceding cover date Next issue: Cover date April 1985 on sale 28 March 1985 Published by: Amateur Radio Magazines, Sovereign House, Brentwood, Essex CM14 4SE, England (0277) 219876 Printed: In England ISSN: 0264-2557 News Trade Sales by: Argus Press Sales & Distribution Ltd, 12-18 Paul Street, London EC2A 4J S. 01-247 8233 Front cover Microwave Modules MMT144/28R 2m transverter, reviewed this month ( p21). -Photo by Jay Moss- Powell G6XIB and Pete Galvin.
Whilst every care is taken when accepting advertisements we cannot accept responsibility for unsatisfactory transactions. We will, however, thoroughly investigate any complaints. The views expressed by contributors are not necessarily those of the publishers. Every care is also taken to ensure that the contents of Amateur Radio are accurate, we assume no responsibility for any effect from errors or omissions.
1 Audit Bureau of Circulations membership applied for C) Copyright 1985
Amateur Radio Magazines
14 DX Diary Don Field G3XTT with this month's DX news
16 Contest Forum A calendar of the 1985 contests on the HF bands
21 Angus McKenzie tests This month G3OSS reviews the Microwave Modules MMT144/28R 2m transverter and the lcom 10551 50MHz rig
29 SWL Trevor Morgan GW4OXB gets involved with an educational project
31 Beginners' workshop Rev George Dobbs G3RJV takes the cheaper road with home construction. This month: getting the bits
38 On the Beam Glen Ross G8MWR with all the latest news from VHF, UHF and Microwaves
40 The dreaded Decibel JGlanville G3TZG removes the myth surrounding this unit of loss and gain
42 Multi P6+ Bill Sparks G8FBX reviews the Rolls Royce of aerials
44 CB conversions This month alook at the dedicated PLL chips used in American CB rigs, and how to get around them
0/P
IC
o
54 Questions and answers Multiple choice questions to test you on your knowledge of the RAE syllabus 57 Coming next month What's in store for you 58 Secondhand Hugh Allison G3XSE looks at some more common faults found in equipment 60 Free Classified Ads The market for buying and selling
SERVICES
34 Newsagents order form 59 Subscription order form 63 Free Classified Ad form 65 Radio and Electronics World
subscription order form 66 Advertisers Index 66 Advertising rates and information
MARCH 1985
please mention AMATEUR RADIO when replying to any advertisement
3
LOWE SHOPS TRIO
Whenever you enter a LOWE ELECTRONICS' shop, be it Glasgow, Darlington, Cambridge, Cardiff, London or here at Matlock, then
you can be certain that, along with a courteous welcome, you will receive straightforward advice. Advice given, not with the intention of ' making' a sale, but the sort which is given freely by one radio amateur to another. Of course, if you decide to purchase then you have the knowledge that LOWE ELECTRONICS are the company that set the standard for amateur radio shops and after- sales service. The shops are open Tuesday to Friday from 9.00 to 5.30 pm, Saturday from 9.00 to 5.00 pm except Glasgow,
which on Tuesdays opens at 10.00 am. For lunchtime closing arrangements, please check with the individual shop.
TS830S
In Glasgow the LOWE ELECTRONICS' shop (the telephone number is 041 945 2626) is managed by Sim GM3SAN. Its address is 4/5 Queen Margaret's Road, off Queen Margaret's Drive. That's the right turn off Great Western Road at the Botanical Gardens' traffic lights. Street parking is available outside the shop and afterwards the Botanical Gardens are well worth avisit.
In the North East the LOWE ELECTRONICS' shop is found in the delightful market town of Darlington ( the telephone number is 0325 486121) and is managed by Don G3GEA. The shop's address is 56 North Road, Darlington. That is on the A167 Durham road out of town. A huge free car park across the road, a large supermarket and bistro restaurant combine to make a visit to Darlington a pleasure for the whole family.
Cambridge, not only aUniversity town but the location of aLOWE ELECTRONICS' shop managed by Tony G4NBS. The address is 162 High Street, Chesterton, Cambridge ( the telephone number is 0223 311230). From the A45 just to the north of Cambridge turn off into the town on the A1309, past the science park and turn left at the first roundabout, signposted Chesterton. After passing a children's playground on your left turn left again ( between the shops) into Green End Road. Very quickly, and without you noticing it, Green End Road becomes High Street. Easy and free street parking is available outside the shop.
For South Wales, the LOWE ELECTRONICS' shop is located in Cardiff. Managed by Richard GW4NAD, who hails from Penarth, the shop ( the telephone number is 0222 464154) is within the premises ( on the first floor) of South Wales Carpets, Clifton Street, Cardiff. Clifton Street is easily found, being aleft turn off Newport Road just before the Infirmary. Once in Clifton Street, South Wales Carpets is the modern red brick building at the end of the street on the right hand side. Enter the shop, follow the arrows past the carpets, up the stairs and the ' Emporium' awaits you. Free street parking is available outside the shop.
LOWE ELECTRONICS' London shop is located at 223/225 Field End Road, Eastcote, Middlesex ( the telephone number is 01 429 3256). The shop, managed by Andy G4DHQ is easily found, being part of Eastcote tube station buildings and as such being on the Metropolitan and Piccadilly lines ( approximately 30 minutes from Baker Street main junction). For the motorist, we are only about 10 minutes' driving time from the M40, A40, North Circular Road ( at Hanger Lane) and the new M25 junction at Denham. Immediately behind the shop is a large car park where you can currently park for the day for 208. There is also free street parking outside the shop.
Although not ashop there is on the South Coast asource of good advice and equipment -- John G3JYG. His address is 16 Harvard Road, Ringmer, Lewes, Sussex ( telephone 0273 812071). An evening or weekend telephone call will put you in touch with John.
Finally, here in Matlock, David G4KFN is in charge. Located in an area of scenic beauty a visit to the shop can combine amateur radio with an outing for the whole family. May Isuggest ameal in one of the town's inexpensive restaurants or a picnic on the hill tops followed by aspell of portable operation.
hf transceiver
The TRIO TS830S is for the operator who wants a dedicated amateur bands only transceiver,who is used to and wants apair of rugged 6146B valves in the PA stage and who wants acompact rig which has its own in-built power supply. The TS830S is for the radio amateur who requires a rig capable of rising above today's crowded band conditions, a rig that has, as standard, the necessary features that will produce consistently good contacts where other lesser equipment would fail. The TRIO TS830S, a proven rig with an impeccable pedigree.
· The TS830S covers on USB, LSB and CW the full amateur bands from 160 through to 10 metres.
Convenient to use, the transceiver has its own in-built power supply.
VBT (variable bandwidth tuning) enables the operator to, at will, vary the IF filter passband width and establish optimum IF bandwidth relative to the interference being experienced.
The IF shift control allows the IF passband to be moved up or down in frequency without having to retune the receiver. Hence, an unwanted signal, present in the IF passband, may be attenuated significantly by moving the passband in the appropriate direction.
As the IF shift and VBT are independently adjustable they can, to advantage, be used together.
The tunable notch filter in the TS830S is ahigh- Q active circuit in the 455KHz second IF. Sharp, deep notch characteristics will eliminate a strong interfering carrier within the passband of the receiver section.
The RF speech processor in the TS830S provides added audio punch and increases the average SSB output power whilst suppressing sideband splatter. Compression levels can be monitored and controlled from the front panel.
To cope with pulse type (such as ignftion) noise, the transceiver has an in-built noise blanker.
For perfect listening, a tone control adjusts receiver audio frequency response to suit operating conditions.
Both RIT and XIT, transmitter as well as receiver incremental tuning are included to aid operating, XIT being a distinct advantage when calling astation that is listening ' off frequency'.
It Is possible to monitor the transmitted audio in order to assess the effects of the speech processor: a most useful feature ensuring perfect signal reports.
TS830S amateur band transceiver £832.75 inc VAT, carr £7.00
LOWE ELECTRONICS
Chesterfield Road, Matlock, Derbyshire. DE4 5LE. Telephone 0629 2817, 2430,4057, 4995. Telex 377482.
4
please mention AMATEUR RADIO when replying to any advertisement
MARCH 1985
TH41E
TS430S
The TS430S combines the facilities of asolid state HF transceiver with those of a general coverage receiver. It's the ideal rig for the radio amateur who not only wants to communicate with his fellows but also enjoys listening to the world. As an amateur band transceiver the rig covers top band to ten metres, as a short wave receiver coverage is from 150KHz to 30MHz. Operating on AM, FM, USB, LSB and CW the TS430S is extremely compact and, as such, is the perfect transceiver for mobile, portable or base station operation. TS430S HF transceiver with general coverage receiver £ 69.50 inc VAT.
TW4000A
Up and down the country are many 70 centimetre repeaters, some 118 as compared with the 62 on 2metres. Perhaps it is this wealth of equipment that can be summoned up at the sound of a1750 Hz tone that now accounts for the increase in activity on 70 centimetres.
TR10, with the introduction of the TH41E, have aworthy transceiver for the 70 centimetre band. The rig is small but size is not its most important feature. It's just the way the transceiver feels when picked up, impossible to put down. Iam not going to give its dimensions, just compare it with the mouse.
Power output is switchable, 1 watt high and 150 milliwatts low. Operation could not be easier. Frequency selection is by means of thumbwheel switches and the TH41E not only has simplex and 1.6 MHz repeater shift but full reverse repeater as well enabling you to quickly check the input, if possible () SY and make for better use of the band.
Ihave personally used a,TH41E through my local repeater, GB3DY and Imust admit that after years of listening and operating nothing has given me as much pleasure as operating the TH41E. As an owner and with the rig always on your person, the hobby of amateur radio expands to an all-day event. Never miss a contact, never miss a friend.
1watt output in high power position, 150 mW in low position.
Full coverage of the 70 centimetre band from 430 to 440 MHz. (TH21E ... 2metre band from 144 to 146 MHz.)
Frequency selection by simple thumbwheel switches.
Full repeater facilities including reverse repeater.
The transceiver comes complete with nicad pack, wrist strap, antenna and charger.
T1441 E . 70 centimetrebicro transceiver £214.50 inc vat. TH21E. 2metre micro transceiver £ 188.46 inc vat.
Taking into account the amount of activity on the 2metre FM channels it is
not surprising that many people have turned their attention to the wide open
spaces of 70 centimetres. With the TW4000A, TRIO have produced a dual
band FM transceiver that gives its owner the best of both worlds. Facilities
include 10 memories, two VFO's, priority channel, full repeater operation,
band scan and memory scan. In memory scan mode the rig can be instructed
to look for either 2metre or 70 centimetre signals. The transceiver produces
25 watt RF output on both bands and comes complete with mobile mount and
microphone. For greater safety whilst mobile the optional VS1 board will
announce frequency, memory channel and whether or not the rig is set on
repeater shift.
TW4000A dual band FM mobile
£536.51 inc VAT.
For those who are banned from the house and have to operate from the shed at the bottom of the garden, why not consider an R600 to monitor the bands from the comfort of the fireside. No wife would forbid such an attractive looking receiver in the lounge, after all it could also be used to listen to Women's Hour. The R600 is a basic receiver covering from 150KHz to 30MHz
and having switched upper and lower sidebands, wide and narrow am and cw. It has a20dB attenuator and anoise blanker fitted as standard. Operation is simple, select the mode of operation, turn the MHz dial to the correct band
and, by using the VFO knob, tune to the desired frequency. The clear digital readout makes station selection simple. The TFII0 R600, your passport to
comfortable listening. R600 general coverage receiver £299.52 inc VAT.
LOWE ELECTRONICS
Chesterfield Road, Matlock, Derbyshire. DE4 5LE. Telephone 0629 2817, 2430, 4057, 4995. Telex 377482.
MARCH 1985
please mention AMATEUR RADIO when replying to any advertisement
5
L·E·T·i·E·R·S
NO AXE TO GRIND
have read with interest the correspondence re the democracy of the RSGB, and
wonder if afew comments from someone with no particular axe to grind will help put things into perspective.
Perhaps Ishould explain that Iam still very much a beginner, having been an SWL for two years, although I have done afair amount of
reading. Ihave also obtained as much literature as possible from both the licensing authorities and the RSGB, with aview to applying for membership of the latter to assist my ambition to become atransmitting amateur.
Imust say that it seems a national pastime for various people to ' snipe' at the RSGB from time to time.
Sometimes they speak for a minority with some particular aspect in mind such as novice licences, but more often it is one individual who claimsto speak for others.
All we get are vague references like ' new blood', 'living in the past', or ' old guard' -- never any list of their supporters or details of changes they would like to see, either in the licensing conditions or the RSGB itself, or indeed whether they intend setting up an
organisation to rival the RSGB.
After all, unlike the motorist who has achoice of two, we have only one national society. Probably just as well, unless the organising ability of some of the critics is more impressive than their logic!
All this is disquieting enough, but imagine my feelings when, upon obtaining another radio magazine recently, Ifound therein aletter from asocalled ' amateur' accusing the RSGB of lying,
misrepresentation and manipulation. Whatever happened to ' Ham Spirit'? Perhaps Ishould change to a more gentlemanly hobby!
However to revert to your pages, in particular the letter from Mr Crosland G6JNS, surely the RSGB is justified in
claiming to represent all amateurs in the UK. After all,
the state of the hobby today is, for good or evil, largely due
to moves instigated by the Society and the licence concessions obtained, which are taken advantage of by members and non-members alike.
Admittedly amuch smaller percentage of the current licensees are now members of the RSGB, but Ithink it dangerous to assume that all the non-members are antiRSGB. Many reasons for failure to join spring to mind -- financial considerations due to unemployment etc, general apathy, even not knowing of the Society's existence because their press and public relations set-up does not seem as vigorous as, say, the CB lobby was fairly recently.
Iwould certainly like to know how Mr Crosland knows the percentage of UK amateurs who agree with his views; has he canvassed them all? In no organisation does one find that all members agree with everyaspect of its affairs, but the members I have spoken to seem in wide general agreement with RSGB policy.
Yes, we all know about the dinosaurs. Many of us have also met many ' new brooms' who were going to work wonders, and we know what happened to them.
Icertainly intend to apply to join the RSGB ( warts and all), having read the pros and cons, and trust that every thinking amateur will do likewise. Kenneth Purdy, Surrey
HAPPY MEMORIES
Imust thank you for the pleasure you gave me in your January edition.
The first item that came to my notice was the article on the Marconi V2A by ' Old Ham'. It took me back to my first job after being pushed out of an elementary school in 1930.
Iworked in amusic and radio shop and we had aV2A with an amplifier, box and horn speaker under the bench. My father bought it with MT and LT and it was our first wireless'. Ialso found a 'Presto' with swinging coils and bright- emitter valves for my own use.
My father used to put his head in the speaker horn to
hear it better! The other item Ifound of
interest was the T1154/R1155 article which reminded me of my RAFVR days. Yes, those were the days when radio was very interesting.
Thank you for an interesting magazine. TWilliams G4SAZ, Kendal
ENTHRALLING
What an enthralling article in the January'85 issue of Amateur Radio. It took me back to my days in the RAF where Iserviced, modified and installed the equipment.
There are still remote parts of the service where these are used, but only last year a great many of these were released by the RAF as surplus to requirements. Many fortunate amateurs managed to buy these, complete and working.
Once, Iowned two of them, but the receivers seemed to suffer from asubstantial amount of electrolytic and small condenser trouble. I still have my air publication on the gear and one day may put it to good use, if Iever manage to buy another 54/55 combination.
The output bottles were PT15s, apair in parallel. They were capable of handling more power, but this was not necessary as some of the older ex- WW2 aircrew used to talk of 5and 9signals between the UK and above the Ruhr valley, although keying was sometimes chirpy and the keying relay had atendency to chatter if one attempted really fast OW.
One of my recollections was the use of the equipment in the Air Training Corps during the 1960s. Iwas responsible for the servicing of several of these sets, also some of the installations. I also worked one at weekends for an ATC unit in the south of England; Iwas acivilian instructor to the ATC.
During the fifties, we used them in the Royal Air Force quite extensively, particularly in the far east. Now that once hostile area regularly sends commercial radio equipment for sale in the United Kingdom. However, one thing is certain, no Korean gear will ever surpass the old Marconi
1154/1155 sets. Incidentally, if anyone has a1082/1083 set to sell, please remember me. Ron Irving G3SYX, Lincs.
MANUAL OFFER With reference to the January issue which included an article on the T1154/R1155: Ihave acopy of an Air Ministry manual on these sets which covers the 71154 A through N, R1155 A through N, circuit diagrams, test procedures, component values, test set type 65, artificial aerial, loop aerial, etc. Iwould like to pass the book on but Idon't know how to ensure that anyone interested in this type of radio could benefit. Iam not as yet a licensed amateur but Iam in the process of studying. Ido not think the book will ever be of use to me personally but must be of value to someone, possibly avintage or collectors club? Perhaps you could give this note amention in the Letters page in case anyone knows someone who could make good use of this original manual. Thanks for avery interesting mag even if half of it leaves me cold. Keep up the good work but remember us dumb ones by including something alittle biased towards the minority of amateurs who find the study hard work. CE Ladley, Lince
GERMAN OM
I'm aGerman OM who would like to start a friendship with an English OM.
Iread your magazine and would be most grateful if you could print the following text in the Letters page:
Itake my holidays in England and would like an amateur radio friend to teach me the English language and to OSO with. He should be in the area of Stevenage, Herts, because Istay in Buntingford with my friends for three weeks each year.
Any offers welcome. Please write to: Ulf Precker DL5IG, Im Oesterling 9, 6951 Binau, W Germany.
Thank you very much for your help!
6
please mention AMATEUR RADIO when replying to any advertisement
MARCH 1985
LETTERS
PERTURBED
Once in awhile, Iam tempted to buy your magazine, most recently for G3OSS on 13cm equipment. Perusing the letters section I was rather perturbed to read Peter Dodson's reply to G1DJV's letter. Idid not see the original article on SWR measurements but G1DJV made an excellent job of criticising asomewhat poor article. Mr Dodson's reply
however, indicates a complete disregard for criticism, however correct it may be.
Without resorting to more criticism of Mr Dodson, Ifeel I
must make afew points on the general subject of technical journalism.
Amateur radio is primarily a
science- based hobby and is precise in all its technical
aspects, so the author should aim to present aset of 100% correct facts. How far these facts are diluted for understanding and the article padded out depends on the author and the editor who should set the overall style. A chatty style of writing is a bonus in electronics journalism, which may help sell magazines, but accuracy should be of prime importance.
The more traditional magazines are often accused of being staid or stuffy but I doubt if they have ever
received aletter such as G1DJV's. Quite simply, most magazines have reviewers who are technically qualified and experienced. If the article is inaccurate it will not be published.
Whether an author is writing 2000 words on a subject, or 20000 words in a
series, he should remember that his words are read by many less qualified people who will take his words as gospel. As aprofessional (writer or engineer?) he
should be striving to maintain excellence and to encourage amateurs to an understanding of the technicalities of the subject,
not churning out fallacies which cause confusion and misunderstanding. 2000 words of fact are much more use than 20000 words of pleasant- sounding drivel.
A magazine has to appoint
its own gurus and in most cases Amateur Radio has
excellent ones, but possibly a
technical reviewer ( with teeth) would be auseful addition to the staff. John Wilkinson G4HGT, Leeds
WITH INTEREST
With some interest Iread the long letter from Mr Whitelegg G1DJV, regarding the articles written by Mr Peter Dodson. Ido not wish to enter the controversy regarding SWR readings, for perfect explanations of antenna matching appear in
many reputable publications and handbooks. Iam surprised that so many misconceptions surround the topic of SWR readings and that often these are printed and appear later in further publications and articles.
The question of Peter Dodson's callsign is intriguing. Most of us who pen articles for the amateur radio press are only too eager to have our correct names and callsigns below our efforts (despite drawing the attentions of the Tax Man!), and Imust only surmise that 'Peter Dodson' is anom de plume hiding the real name of alicensed amateur. It is inconceivable that Dodson's articles could have been written by someone not having experience as a transmitting amateur. Why is our friend so eager to hide his true identity?
Imust before conciuding take task with Dodson on one point which Ifeel is important. Has he actually tried and used the antennae that he describes, or is he just 're- hashing' existing information from other sources? Ionly write about antennae that have been personally made and used by myself and would consider
myself something of a charlatan were Ito enthuse about an antenna that Ihad only read or heard about at secondhand. On the few occasions in my articles that I mention an aerial system that Ihave not used myself Imake such apoint quite clear to the reader. John DHeys G3BDO, Hastings
APPALLING BARRAGE
As radio amateurs, we often refer proudly to our membership of agreat international fraternity. An admirable concept of course, but in one respect at least it does not hold good.
Irefer to common DX hunting practices, when the surfacing of agood DX station immediately banishes all semblance of brotherly respect and tolerance from the bands. For prolonged periods the rare bird is subjected to an appalling barrage of bedlamic noise, as dozens of shouting predators descend upon him. Nobody ever dreams of giving way to the other fellow, and the pernicious doctrine of might is right' sadly prevails.
Surely this picture leaves much room for improvement, if operational courtesy on the air is not to join the dodo in extinction.
I'm glad to say that this is my only beef after eight years of otherwise enjoyable involvement.
Meanwhile, congratulations on your excellent magazine, which I
await eagerly each month. Pat Mooney El6DA, Dublin
SUGGESTIONS PLEASE At present Ihave no involvement with amateur radio and would class myself as relatively ignorant in this respect. However, Iam very interested in taking up this pastime and would be most grateful if anyone could suggest the best and, Imight add, least expensive method of doing so. Perhaps, in addition, someone could recommend some appropriate reading matter. May Itake this opportunity to compliment Amateur Radkson what Iconsider to be awell written, balanced and informative magazine. M W Anderson, Newcastleupon-Tyne
CAN YOU HELP?
Iam areader of Amateur Radio and would like to ask your readers if they can help me.
Iwould like to know if my rig can be converted to cover the 2m and 144M Hz bands for use when Ipass the RAE.
Ihave aPye Westminster VHF, AM, type 15AM transceiver which has a10 channel Tx/Rx with crystals. At present it covers the 6874M Hz band and is used with a mains power supply, although it has a12V connection.
As lama pensioner Icannot afford an expensive rig, yet I wish to enjoy this hobby to the full before age catches up with me.
Thank you for an excellent magazine. Keep up the good work. Richard Freeman, Sunderland
INCENSED
Ihave just read the article Justice/Injustice by Hugh Allison G3XSE in the February edition of Amateur Radio and Iam appalled. In fairness both the Police and the RSGB should now be invited to answer Mr Allison's allegations.
The matter is adesperately serious one. Either certain policemen in the Harlow area are quite insufferable and unfit for their jobs, and G3XSE is justifiably incensed, or there were reasonable grounds for their behaviour.
Can we hear their side of it? If G3XSE is justified then what has been done to restore the Police force involved to good behaviour? Ronald JMarshall, Gourock
GB STATIONS Apart from contests, undoubtedly the worst operating can be heard from the experts' who hold forth with such pomposity when in charge of the mike at a 'special event' station given a GB callsign! So might Ihave the audacity to suggest that in future these stations be licensed to use CW only; that would cut the cackle, and incidentally, prove to be much more interesting. Douglas Byrne G3KPO, Ryde
MARCH 1985
please mention AMATEUR RADIO when replying to any advertisement
7
STRAIGHT LEVEL
All the latest news, comment and developments on the amateur radio scene
CIRCUIT MAKER
Electrolube
have
introduced the CM100 Circuit
Maker Kit which they claim is
one of the first DIY kits on the
market to offer a complete and easy- to- use system for
producing printed circuit
boards. It is ideal for the
expert hobbyist or those
wishing to try their hand at
electronics.
This versatile kit enables
hobbyists to produce layouts
from magazines and other
sources using an easy four-
step system which is
explained in adetailed set of
step-by-step
instructions.
These steps include produc-
ing a film positive master of
the chosen PCB design,
etching of the board using photo- resist, removal of the
photo- resist and finally drill-
ing and component assembly.
Advantages of the CM100
kit include the photographic
development system which
allows professional quality
circuit boards to be produced
without a darkroom, camera
equipment or ultra violet
lights, and the ease of use
makes previous photographic
experience unnecessary.
Electrolube now offers
items from the CM100 Circuit
Maker Kit separately, which
will allow hobbyists to supple-
ment their existing equip-
ment and supplies. Included
in this list of items is a
specially designed universal
assembly frame which is use-
ful for drilling and component
assembly, developers, fixer
and clearing solutions for the
auto- positive film, photo-
resist and developer, and
double- sided copper clad
boards. A useful asset for electro-
nics hobbyists, the CM100
Circuit Maker Kit is very
adaptable and can be tailored
to suit the needs and
demands of various situa-
tions. Electrolube Limited, Blakes
Road, Wargrave, Berkshire RG10 3014. Tel: (073) 522 3014.
ANALOGUE MULTIMETER
TMK Test Instruments have announced the VF3, a small pocket size analogue multimeter, featuring a full range of functions with a high sensitivity of 2000 ohms/volt on all dc and ac ranges, assuring accurate measure-
ments without unnecessary loading of the circuit under
test. Included in the 16
measurement ranges are dc and ac volts, dc current, ohms and decibels.
Rugged and reliable with a high impact resistant case,
the VF3 is very easy to use. It has a single rotary switch
giving analogue indication on a mirror arc scale to reduce parallax error and the meter movement is protected against accidental over- load.
The VF3 comes complete with test leads and a longlasting battery. It weighs approximately 90gms and its
dimensions are 90 x 60 x 29mm.
TMK Test Instruments, 138 Grays Inn Road, London WC1X 8AX. Tel: (01) 837 7937.
RTTY CONTEST
Peter Adams G6LZB has
sent us some information on
the BARTG Autumn RTTY
Contest 1984:
'The vast increase in our
membership
certainly
showed in the number of
stations active throughout
the contest. However, Istill
only received 22 logs for the
single operator section and
13 for the multi- operator sec-
tion. Iwonder why stations
don't send them in?
'Conditions
certainly
improved during the contest
and a number of stations
worked well into the Conti-
nent. The best DX contact
appeared to be the one
between GW2OP and PE1 IML
at 682Km.
'With such a large number
of stations active, the
possibility of claims for the
VHF Century Award seem
very good.'
G6LZB reports that 191 Brit-
ish stations participated.
The Spring VHF/UHF RTTY
Contest will take place
between 1800 GMT on Satur-
day 13 April and 1200 GMT on
Sunday 14 April. Further
information and contest rules
are available from the BARTG
Contest Manager, Peter
Adams G6LZB, 464 Whippen-
del I Road, Watford, Herts
WD1 7PT. Completed logs
should also be sent to this
address.
ATV CONTEST
Congratulations to G8MNY for coming first on 70cm and to G8VBC for winning the 23cm section in the September ATV contest. Certainly conditions were not at their
best: G6WOR/P, who could almost see the Channel, worked no continentals and ON7ZI and GU8FB0 were the only DX stations available in the south -- and then for only a few minutes at atime!
However, the level of activity on both 70 and 23 was better than ever and shows just how much interest continues to grow in ATV.
We received the following comments from contestants:
'We hoped this year would
have better weather but a storm in the middle of the night took out the 70cm mast at 45 feet; it snapped in two but was put up to 28 feet within an hour at 0345r -- G8MNY.
'Conditions were horrible
but Ienjoyed it.' -- G8VBC. 'The 23cm receiver could
have been better if we had fitted the mast- head pre- amp the right way round!' -- Anon.
ATV enthusiasts' attention is drawn to the annual Summerfun Contest scheduled for 0900 to 1600GMT on Sunday 16 June, this being the first ATV contest using the
new Maidenhead locators.
Contest rules appear in CQTV no129.
Please note that the contest organiser ( G3VZV QTHr) prefers entries on BATC log sheets, available from him on receipt of an SAE.
MISPRINT
In the Dodson at Random
feature in the January issue
of Amateur Radio entitled
'CW reception' amisprint was
included in Table 1. The table
listed the components and
their values required for the
conversion of a receiver for
CW reception.
The resistors numbered R2,
3, 4, 10 and 13 should have had
the value of 24K11 and not
240K2 as printed.
We apologise for the mis-
take
and
regret
any
inconvenience caused.
TINNING
In the January edition of Amateur Radio the Beginners' Workshop feature, written by Rev George Dobbs G3RJV, included some advice on the tinning of soldering iron bits.
On the magazine's publication we received aletter from
Antex ( Electronics) Ltd which made the following point:
'The advice given regarding
8
please mention AMATEUR RADIO when replying to any advertisement
MARCH 1985
STRAIGHT & LEVEL
the tinning of the bit is
erroneous. The bits are plated with aheavy deposit of iron followed by a layer of chromium and nickel; the object being to save them from the extremely corrosive
effects of the flux which is so essential to the soldering
process. 'We estimate that filing the
tip back to bare metal, as the author advocates on page 28, would reduce the projected life of the tip by about 75%, when life is the number of joints which can be soldered
before the form of the tip has corroded beyond use.'
FROM THE BOOKSHELF
This month we take alook at
three books which may be of
interest to the hobbyist. The
first is objectively titled
Amateur
Radio,
Super
Hobby!, written by Vince
Luciani K2VJ.
VOklitt It Is. Who Vie Ant How To
WPM 11111111111
Uwe LKZW .21
As the author's callsign indicates, the book is of American origin and therein lie the two major drawbacks for the British reader. Firstly, much of the useful ' getting started' information provided by the book is completely irrelevant on this side of the Atlantic, and many of the lyrical descriptions of the hobby just do not apply here.
Secondly, and perhaps more infuriating to the potential reader in the UK, is that the author's pseudo nontechnical style often amounts to little more than clichéridden West Coast American jargonese ( typified by the book's sub- title, What it is, who we are, how to join', which given the author's name seems to make the whole book sound like a recruitment leaflet for the
QST mafia).
The book may have suc-
ceeded in creating interest in
the hobby in the US, where at
least it is accurate and
relevant, but to suggest it
could ever perform the same
function here is both cynical
and erroneous.
Even for US readers, abook
which contains such predict-
able chapters as those on
Barry Goldwater ( K7UGA-- for
those few on this side of the
Atlantic who don't know),
Wayne Green et al. must
surely lay its integrity and
usefulness on the line as
clearly as it does its carefully
contrived vision of ' ham'
camaraderie ( been listening
to any of those polite, high
power US stations during any
of the recent contests?).
The book is of interest for
some of its anecdotes, and as
an insight to how American
amateurs see their own fra-
ternity (' how to join' again),
but its ' foreign' nature and
self-congratulatory
smug-
ness make its purchase a
waste of money, and its read-
ing agonising and ultimately a
waste of time.
If it was in your local library
I'd advise you to get it out for a
week; if you were a librarian
asking for suggestions for
books on the hobby, I'd tell
you not to touch it -- even if
you had a bloody great barge
pole.
What the book does do is
suggest that there should be
areadable introduction to the
hobby as it exists on these
shores, something which per-
haps our friends at the RSGB
could be looking into ( to
complement Pat Hawker's
excellent Guide to Amateur
Radio, which is nonetheless
aimed at those who have
already decided to enter the
hobby).
To this end, any sugges-
tions for atitle for such abook
would be gratefully received
by the Editor. Hopefully these
will be less crass than ' Super
Hobby!' -- the best will be sent
to the RSGB, and just to make
it all worthwhile, whoever
sends in that ' gem' will
receive a free copy of that
epic volume Amateur Radio,
Super Hobby!, which is no
longer required at this
address.
The second book looked at
this month is also ' foreign',
but
despite
struggling
against ( and suffering from)
translation from the original
German, brings greater
rewards to the interested reader. Ninety Nine Nights on Medium Wave provides an enthusiastic and functional introduction to MW DX.
The book is based around a survey of DX conditions and
results over a three month period. Apart from showing what can be achieved through regular listening on these bands, the book provides essential information for the beginner in the form of
names, frequencies and addresses of the more common stations to be logged, along with technical information and advice on this challenging form of BC DXing.
Above all, this book belies its simple form and sometimes ragged grammar to
convey the enthusiasm and dedication required in this branch of the radio hobby in a way which makes Amateur Radio, Super Hobby! look like the result of too many monkeys with too many typewriters.
The third of this month's
books is one that comes
heartily recommended: the
Computer
and
Tele-
communications Handbook,
by Jeff Maynard. Surprisingly
enough, this book is not
American, or German, but
British! It is also invaluable,
expensive ( well, it is British)
and worth the money.
The book is a source of
reference
that
brings
together many pieces of
information which previously
had to be dug out from a
variety of sources, and is,
quite simply, a compendium
of those ' silly- little- facts- that-
must- be- lying- around- some-
where' that we all need from
time to time.
If your hexadecimal has got
a bit rusty, or if you can't for
the life of you remember the
meaning of QSC during an
SOS call; if you want auseful
bandplan up to 150MHz; if
you're not quite sure whether
ASCII is a form of computer
code or an engineering
degree; if you want the facts
about FAX and a lot of other
facts as well: you could do
much worse than invest in this
book.
Calculations,
standards,
codes, components, symbols,
theories, callsigns, conven-
tions and maths: they are all
here, waiting to be of help.
Maybe if there's enough
demand this book will appear
in paperback; when it does, it
will become required reading
for all in the hobby -- partic-
ularly those who through the
use of data transmission
attempt to fling the hobby into
the twenty-first century.
Other twentieth century mor-
tals may prefer Amateur
Radio, Super Hobby!: Ihope
not. For God, BARTG and the
21st century, Ihope we realise
that even ' pulp' can be well-
presented, even ' talking
down' to beginners need not
involve condescension.
If the Computer and Tele-
communications Handbook is
merely asource of reference
to the world which Amateur
Radio, Super Hobby! sup-
posedly describes, then for
the time being I'll stick to the
dictionary, and skip the novel.
Amateur Radio, Super
Hobby! McGraw-Hill Book Co
(UK) Ltd, Shoppenhangers
Rd, Maidenhead, Berks.
Ninety Nine Nights on
Medium Wave. Wilhelm
Herbst, PO Box 45 05 06, D-
5000 Kóln 41, Fed Rep of
Germany.
Computer
and
Tele-
communications Handbook.
Collins Professional and
Technical Books, 8 Grafton
St, London Wl.
MARCH 1985
please mention AMATEUR RADIO when replying to any advertisement
9
STRAIGHT 8( LEVEL
CLUB NEWS
25th anniversary
It is with pleasure that the
Blackwood and District
Amateur Radio Society
announce
the
25th
anniversary of the club.
As part of the celebrations
the club has put together an
award to help bring B&D ARS
to the attention of other
amateurs.
The contest/awards are
open to non-members only,
although the member whose
callsign appears most fre-
quently on the claimants' log
sheets will be awarded a
certificate. There is also an
award for the SWL member of
the B&D ARS who logs the
highest number of members'
callsigns in the twelve month
period.
Applications for rule sheets
and information to: Black-
wood and District ARS, c/o
GW4VVX, PO Box 21, Black-
wood, Gwent.
STARS Award The Stowbridge and Dis-
trict Amateur Radio Society is offering the STARS Award to both licensed amateurs and listeners who work/hear STARS members on at least two amateur bands.
Applicants have to have worked a minimum of 9society members, and by taking one letter from the suffix of 5
of the members' callsigns spell out STARS.
There are no mode restrictions.
Full details are given in the list of rules available from: John Shells G6VAT, 5 Ombersley Road, Hallesowen, West Midlands B63
4PJ. Please enclose an SAE.
Bury Radio Society
At the general meeting on
11
December
several
changes were made to the
committee of the Bury Radio
Society. Their chairman is
now Mike Bainbridge G4GSY
whilst G3VNQ has taken over
as editor of 'Feedback', the
society's bi-monthly journal.
The journal includes all
club news and articles of
interest, such as one entitled
French lessons for the radio
amateur.
The society meets every
Tuesday evening at 8.00pm in
the Mosses Community Cen-
tre, Cecil Street, Bury. The
main meetings are held on
the second Tuesday of the
month; the remaining meet-
ings are informal.
For further information please contact: Hon Secretary Brian Tyldsley G4TBT, 4 Co/ne Road, Burn-
ley. Tel: Burnley 24254.
Brldgend and District ARC The Bridgend and District
Amateur Radio Club has appointed a new chairman: Mr Don Sedgebeer GW3RUG.
The club meets on the first and third Friday of every month at the YMCA, Bridgend, Mid Glamorgan. Meetings start at 7.30pm and further information is available from the secretary at the undermentioned address.
T C Morgan GW4SML, 4 Rhiw Tremean, Brackla, Bridgend, Mid Glam, South Wales.
East Lancashire ARC
The
East
Lancashire
Amateur Radio Club ( G3NTJ,
G1ELC) meets twice a month
at the Conservative Club,
CI iffe Street.
On the first Tuesday of every
month at 7.30pm they have a
lecture or demonstration and
on the last Tuesday an
informal meeting. On the
Tuesdays they do not meet
there is a club net on
145.400MHz at 7.30pm.
On the schedule for the
next two formal meetings, on
5March and 2April, they have
asurplus equipment sale and
avisit from the local police for
atalk on crime prevention.
Further information regar-
ding meetings and club
events can be obtained from:
Stuart Westall G6LXU, 19 Sus-
sex Road, Rishton, Blackburn,
Lancashire BB1 4BJ.
Components fair
The Pontefract and District
Amateur Radio Society
(G3FYQ, G1FYQ) are holding
their components fair on Sun-
day 10 March from 11.00am to
4.30pm at the Carleton Com-
munity Centre, Pontefract.
The event is based on the
mobile radio rally but it is
aimed at the home construc-
tor and the do-it-yourself
enthusiast.
Traders are invited to sell
components, surplus equip-
ment, instruments and anten-
nae. New black box type of
equipment is not allowed at
this event.
For further information
please
contact
the
organisers:
N Whittingham G4ISU; Tel:
(0977) 792784. R Greenhough
G4KMW: Tel: (0977) 792654.
Southend RS Rally The Southend and District
Radio Society will be holding a mobile rally at the Rocheway Centre, Rochford, Essex on 28 April.
Talk- in on S22 145.550MHz FM is available, although there will be adequate road signs. There is ample parking, including on site facilities for disabled visitors.
Black boxes, components and bring-and-buy stalls are some of the attractions which will be supported by the statutory refreshments and licensed bar.
For further information contact: Bryn G4DEZ; Tel: (0702) 617749 or Brian G4RDS: Tel: (03745) 50494.
Radio and Computer Fair The North Wakefield Radio
Club is holding an Amateur Radio and Computer Fair at Bretton Hall College, Bretton on 8April.
Doors open at 11.00am (10.30am for disabled visitors) and all the usual attractions including radio, computers, electronics and bring-andbuy stalls will be included, with the addition of handicraft stalls and film shows for the rest of the family.
Talk- in will be available on S22 and GB3WV ( RB15).
For dealer or visitor enquiries contact: Steve Thompson G4RCH, 2 Alden Close, Morley, Leeds LS27 OSG. Tel: (0532) 536633.
BATC rally The BATC will be holding its
Amateur Rally at The Post House Hotel, Crick on 5 May. This pleasant location for a rally is located less than 200 yards from the M1 at Junction 18. The doors open at 10.00am and admission is free.
All the usual traders will be in attendance. There will also be a full supporting lecture programme including talks on colour SSTV, interfacing to the Spectrum computer, and amateur television techniques.
The famous Post House lunch is available by prior arrangement as is overnight accommodation at special terms for those attending.
To make bookings contact: The Post House. Tel: (0788) 822107.
2nd Anglo-Scottish Rally Following their highly
successful inaugural event in 1984, the joint organisers
Kelso,
Borders
and
Galashiels amateur radio
societies will be hosting the
2nd Anglo -Scottish Rally in
Kelso's Tait Hall on Sunday 5
May 1985 from 11.00am to
5.00pm.
There will be the usual
stalls, talk- in on S22, CW
testing station, bar, hot and
cold snacks, raffles etc.
Entrance will be £ 1.00 --
Junior ops, YLs and XYLs very
welcome and admitted free.
Something to do for
everyone.
For further information,
including accommodation,
contact: André Saunders
GM3VLB, Physics Dept, Kelso
High School, or Bruce Cavers
GM4UIB, OTHr. Tel: (0573)
24664 and 24654 (evenings
only).
WIA 75 Award The world's first and oldest
radio society, the Wireless Institute of Australia, celebrates its 75th anniversary during 1985.
One of the many planned activities is the WIA 75 award which will be available during
the period March 1to December 31 1985.
To qualify, radio amateurs (and short wave listeners) need to contact ( log) 75 members of the Wireless Institute of Australia. A contact will only be valid if the WIA member's individual membership number is
logged. No more than 30 WIA mem-
bers may be logged in anyone callsign area.
Claims should include alog extract of the 75 WIA members contacted, $2 ( Aust) to cover the certificate, handling and postage costs, and be sent to:
WIA 75 Award Manager, Wireless Institute of Australia, 412 Brunswick Street, Fitzroy 3065. Victoria, Australia.
Amateurs help chartty The Southgate Amateur
Radio Club will be operating a special amateur radio Station, for 48 hours . over the
weekend of 30/31 March 1985. In support of the Mayor of Enfield's charity appeal, the club will be sponsored for every country that they make
contact with ( there are over 350 countries in the world).
Further information is avail-
able from: Mr R F Snary, SARC, 12 Borden Avenue, Enfield EN1 2BZ.
10
please mention AMATEUR RADIO when replying to any advertisement
MARCH 1985
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11
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MARCH 1985
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MARCH 1985
please mention AMATEUR RADIO when replying to any advertisement
13
IIAR
News for HF operators compiled by Don Field G3XTT
The low frequency bands started the year well and by mid- January much exotic DX was being worked, including
such stations as HC1BI, 9Y4VU, 6Y5 IC, 3B9CD, AP2SQ, W6, W7 and JAs, and all of this on 160 metres! In addition, the CO WW 160 metre OW Contest at the end of the month produced contacts for UK stations with KV4FZ, YV10B, RT5UL/UJ and others.
Compared with all this
there was very little to report on 20 and 15 metres and nothing whatsoever on 10. What is more, there has been some debate about whether the sunspot minimum might actually come later than ori-
ginally anticipated, so we could well have to put up with these ( or worse) conditions for another 3 or 4 years at least. Time perhaps to put up that 40 metre beam or the phased verticals that you
have always promised yourself.
Cyprus -- now two ' countries'
In January the ARRL Awards Committee approved the earlier recommendation of the DX Advisory Committee that the British Sovereign Base areas on Cyprus count as a separate DXCC country. This is the first new ' country' to be added to the DXCC list since 1981 when 1A0 (Sovereign Military Order of Malta) was accepted.
This latest addition follows a submission to the ARRL which included evidence showing that, when the remainder of the island was given its independence in 1960, the British government
specifically excluded those areas where the two British
bases ( Episkopi and Akrotiri)
were located. Britain retains complete sovereignty over
those areas which cover some 100 square miles in total. British law applies and, most importantly from the amateur radio point of view, licences are issued by the Joint Signals Board, RAF Episkopi, rather than by the Cyprus authorities. A British
amateur living outside the
base areas but working within
one of them would need both a564 and aZC4 licence if he wished to be able to operate
from both his home and his work 0TH.
There is no reason to expect this ARRL decision to open the floodgates to other applications for ' country' status. To take an example, the US air bases in Britain are all
leased from the UK government and are still British sovereign territory. Guanta-
ZC4 and 584 are now two countries
ZC4IK
POST OFFICE BOX 216
FAMAGUSTA-CYPRUS
namo Bay on the mainland of Cuba does, of course, count as a separate country ( with the prefix KG4), although it is leased by the Americans from Cuba. However, it would not be acceptable as a DXCC 'country' under the rules which currently apply.
How to claim the new one The burning question for
DX- minded amateurs is how they get the new country added to their DXCC total. The ARRL has said that cards may be submitted any time after 1 June. All 5B4 cards, and all ZC4 cards for contacts prior to 16 August 1960, count as Cyprus. Since that date ZC4 cards may count for either Cyprus or the British Sovereign Base areas ( to confuse matters, not all ZC4 operations in the past have actually been from the Base areas). If, therefore, your existing DXCC credit for Cyprus is aZC4 card you will need to resubmit it so that ARRL can make a ruling on which 'country' it counts for. The best bet is to send a5B4 card if you have one, along with several ZC4 cards, one of which will, hopefully, be accepted as counting for the new country.
Now 316 countries The addition of ZC4 to the
list brings the number of current DXCC countries to 316. There has occasionally been talk in the past about moves to have ZC4 counted, but no one seems to have got as far as aformal submission to the ARRL. There may be some ZC4 amateurs who are less than happy about their
14
please mention AMATEUR RADIO when replying to any advertisement
MARCH 1985
DX DIARY
newly acquired fame, but one cannot stand in the way of the facts. ZC4 and 5B4 have, in fact, much greater claim to be separate countries than do, say, England and Wales or France and Corsica.
Clipperton Island
The Clipperton Island
expedition which Imentioned
in the January column is still
scheduled to depart San
Diego on 27 March, collect
the operators in Mexico on
the 30th, and start operations
on 3 April. They will stay on
the island for 7 or 8 days
depending upon the exact
date of arrival. The boat used
will be a 115ft sport fishing
vessel, the ' Royal Polaris'.
Hiring a boat in the USA is
more expensive than hiring in
Mexico, but the group hope it
will avoid a repeat of last
year's debacle when the boat
failed to materialise.
The operators will include
W6SZN, W6OAT, W6RGG,
N6GJ, KK6X, N7NG, K3NA,
WA7NIN,
F6GXB,
F9LX,
DJ9ZB, TI2CF, XE1ZZA,
JG3LZG, FO8HL and FO8GW.
No callsign has been allo-
cated to the expedition at the
time of writing. The group
hope to have 3 stations
operating round the clock on
10-160 metres with CW, SSB
and RTTY if possible. They
may also be equipped for 6
metres and for Oscar. Inci-
dentally, don't be surprised to
hear them on both CW and
SSB simultaneously on a
single band.
Costs Costs of the expedition will
be $3500 per operator and contributions are urgently sought. These should be sent to the Northern California DX Foundation via W6OAT and all donations will be acknowledged in writing. QSLs will be handled by the YASME Foundation whose address has appeared in earlier columns.
It now looks as though no
operation will take place from the Mexican island of Revilla Gigedo en route to Clipperton, but a Mexican group were talking about making their own trip to XF4 in late February or early March.
Other news K4LTA was scheduled to be
active from Dominica ( J7)
from 15 February to 5 March. From past experience Iwould suggest looking for him
Mike G4IUF in his shock
around 14025 and 7005KHz and also on 10MHz.
Port Talbot GB2SDD is a special event
call to be used on 1March by the Port Talbot Amateur Radio Society to commemorate St David's Day. A certificate is available for contacting GB2SDD and 10 other GW stations during February and March. Claims should be sent (with 6 IRCs or equivalent) to R Jones GW4H0Q. Incidentally, if any readers are planning to use aGB call for a special event Ishall be happy to publish information in this column provided you give me sufficient notice.
AB4Y has been reported operational from Mozambique with the callsign C90A; CiSL to WM4N. Although there have been several operations from Mozambique since its independence from Portugal, none have been legitimate. We can only hope this is the exception. It is interesting to reflect that, as recently as the early 70s, CR7 calls from Mozambique were some of the most frequently heard on the bands.
Special prefixes A number of special pre-
fixes have recently been on the air from the USSR to commemorate victory in Europe. EM, EO, EV, EW and other similar prefixes have been heard. Don't forget to work them towards your Amateur Radio magazine Prefix Award. In fact, you can kill two birds with one stone because the ' Pobeda 40' award will be available from Box 88, Moscow for working 40 of these special stations.
Also counting towards this latter award are a number of war veterans who are using their own call, / R.
Navassa Island
If you still need a contact
with Navassa Island, stay by
your rig on 6/7 April because a
group of Jamaican amateurs
have been talking about an
operation
from
there.
Navassa is quite easy to reach
from Jamaica, but is uninha-
bited and with steep cliffs, so
getting gear, generators, etc,
ashore is always a problem.
Montserrat Dave W2WSE should be
active now as VP2MDB and will be there until 17 March. I
was interested to have the opportunity recently to see G4JVG's slides of the October 1984 contest operation from Montserrat as VP2MW by agroup of UK amateurs. Two holiday homes are available for hire on the island, fully
equipped with stations, towers and antennae, for use by visiting amateurs. Air fares tend to be prohibitive in the main tourist season, but pick the right time of the year and you can have a combined holiday/DXpedition for a fairly reasonable sum, especially if you go with a small
group of others to share the cost of the holiday home.
In November Imentioned that George Collins VE3FXTF was planning a trip taking in 100 countries during 1985. Unfortunately George's wife VE3C0A/G3YXT passed away recently and George has
abandoned his trip. Another cancelled trip is that to Southern Africa by Lloyd and Iris Colvin. In their case the
cancellation was due to business commitments in their native California.
YI1BGD in Baghdad has recently been quite active on 80 and 40 and has now been given permission to operate on the new 18 and 24MHz bands. YI1BGD is a club station and the only station currently active from Iraq.
Another country from which little is heard at present is Thailand. Latest news is that the Minister of Telecommunications has made representations to his government colleagues to allow amateurs back on the air, so keep your fingers crossed. Meanwhile there are occasional operations by the club station HSOA by special permit.
4X5DS is the call to be used from 0800 on 6April to 0800 on 13 April. This station will operate from the lowest lying land on earth, at Ein Gedi near the Dead Sea. Special QSLs will be issued, as will an award for working the station on: ( 1) at least 3days of the expedition, ( 2) at least 3bands, or ( 3) all 3modes ( CW, SSB, RTTY). Activity will be on 80-10 metres.
DX News Sheet In July of last year Idevoted
much of this column to sources of DX information. The UK's principal organ is the RSGB's DX News Sheet which, since 1 January, has been edited by Brendan McCartney G4DY0. If you want to subscribe to DXNS then drop aline to the RSGB.
US Conventions Also for those of you with a
desire to travel, the Californian DX Convention takes place on the weekend of 19-21 April, this year back at its old venue of Fresno. The Dayton Hamvention, an enormous affair which always has a number of visitors from the UK, takes place on 26-28 April.
And Finally ... Did you work PA6FLD in
February? This was aspecial station to celebrate the opening of a new transmitter site by Radio Nederland. The station was able to use the massive curtain array antennae ( 20dB gain or thereabouts) before they went into service for short wave broadcasting. Wonder if they would mind lending the station out for acontest ... ?
MARCH 1985
please mention AMATEUR RADIO when replying to any advertisement
15
CONTEST FORUM
Most major national amateur radio societies in the world organise a programme of HF contests. The RSGB is no exception! The RSGB currently runs 17 HF contests each year as well as aseries of HF cumulative contests. Whereas most national societies run one or two major HF contests each year, the RSGB runs a mixture of major and minor HF contests.
A CALENDAR OF 1985 EVENTS
The majors
For example, in the US the ARRL runs two very major contests: the ARRL DX CW and SSB contests which are held annually. For stations outside the USA and Canada, the idea is to contact as many USA and Canadian stations as possible on all of the HF bands.
The German society ( DARC) also· organises aseries of major international contests. The DARC runs the panEuropean contests, WAE-CW, WAE-SSB and WAE-RTTY, in which European stations make contact with stations outside Europe.
Once- a- year major contests such as the ARRL DX contests, the WAE contests and the CO Worldwide DX contests usually run for afull 48 hours.
Many other national societies organise HF contests at different times throughout the year. Most national HF contests are held on the ' same weekend' in each year. For example, the ARRL DX CW Contest is always on the third ' full' weekend in February and the SSB section is on the first ' full' weekend in March. The first full weekend is when both the Saturday and the Sunday are in the same month.
Defining the timing of major international contests in this way avoids the confusion that would arise by using just the dates alone. Traditionally many weekends in the year have been ' booked' for years by particular contests. Any proposals for dates for new contests always have to take into account the existing ' status quo' of the international contest calendar in order to avoid contests clashing with each other.
RSGB
Rather than having asingle once- andfor- all major HF contest each year, the RSGB runs a range of different HF contests for both inter- G working and outside- G working on the HF bands. Over the years the RSGB has built up a tradition of smaller and more specialised contests. RSGB HF contests are usually on just one or two bands and are of short duration.
Short sharp contests are now very popular and with good reason too. There are not many radio amateurs who can easily devote awhole weekend to taking part in aradio contest. 48 hours is just too long ( well, more than once or twice ayear anyway!). But contests that last four or five hours are popular because the short length of the contest means that participants can be there all the time and are
NIGEL CAWTHORNE G3TXF
Contest
AFS RSGB 7SSB First 1.8MHz RSGB 7CW Commonwealth Town & County ROPOCO I Low Power Fixed Region- Round- up NFD-HF CW Field Day Summer 18MHz Low Power Field Day ROPOCO II IARU SSB Field Day RSGB 21/28 SSB RSGB 21 CW Second 1.8MHz
Mode Dates ( 1985)
CW SSB CW CW CW SSB CW CW CW CW CW CW CW SSB SSB CW CW
Jan 13 Feb 2-3 Feb 9-10 Feb 23-24 Mar 9-10 Mar 16 Apr 7 Apr 21 May 19 Jun 1-2 Jun 22-23 Jul 21 Aug 25 Sep 7-8 Oct 13 Oct 20 Nov 9-10
Day : Time
Sun 13Z to 17Z Sat 12Z to Sun 09Z Sat 21Z to Sun 01Z Sat 12Z to Sun 09Z Sat 12Z to Sun 12Z Sat 21Z to 242 Sun 082 to 10Z Sun 07-11Z & 13-17Z Sun 07Z to 12Z Sat 16Z to Sun 16Z Sat 21Z to Sun 01Z Sun 09Z to 12Z & Sun 13Z to 16Z Sun 08Z to 10Z Sat 15Z to Sun152 Sun 07Z to 192 Sun 07Z to 19Z Sat 212 to Sun 012
Band (MHz)
3.5
7
1.8
7
3.5 to 28
1.8
3.5
3.5 & 7
3.5 & 7
1.8 to 28
1.8
3.5
7
3.5
3.5 to 28
21 & 28
21
1.8
able to work as much as they can within the time, without having to take too much time away from other commitments.
In the RSGB's HF contest calendar there are now ten contests which are short and sharp. These are the four Top Band contests, the two ROP000s, Region- Round- up, the two low power contests and the Affiliated Societies Contest ( AFS).
AFS
The Affiliated Societies CW Contest runs for just four hours on 3.5MHz on a January Sunday afternoon. Along with the HF National Field Day, AFS is arguably one of the best operating events of the year on the RSGB's contest calendar. Over 20,000 OSOs were made in AFS last year in just four hours!
Each entrant makes as many contacts as he can during the four hours of the contest. Logs are then passed to the AFS entry co-ordinator for each club or society, who puts the logs together and prepares aclub/society summary sheet. Operating teams consist of up to five members in each team. Clubs may enter more than one team. Some clubs enter up to three teams.
The team score is the sum of scores made by each member of the team. As well as a team listing, there is also an individual operator listing in the results.
No doubt because of its convenient length and timing, AFS has become a major inter- G HF CW operating event over recent years.
HF National Field Day
HF NFD has been running for over fifty years and is a well supported event. Many HF CW operators who may never touch a key during the rest of the year make aspecial effort to get on the air for
NFD! NFD is ateam event too. Unlike AFS where each member of the team operates from his home 0TH, for NFD the team comes together to put a multioperator club station on the air. After
weeks of planning and preparation, the NFD club team sets up a portable HF station and keeps it running for the 24 hours of the contest.
The RSGB's NFD is deliberately timed to coincide with similar field day events being organised by other European
societies. Large numbers of contacts with German, Swiss and Belgian portable stations are easily made on the lower bands. During this one weekend there are hundreds of portable HF amateur stations operating all over Europe. There are also occasional DX portable stations
active during NFD, but for the most part NFD is a contest for working UK and
European portables. NFD is not just an operating event for
the contesters, but can also be a major
social event for many radio clubs and societies. Setting up tents in damp fields, keeping cows and other beasts away from the operating tent and the kitchen area, as well as keeping the generator chugging over are all the sort of tasks
made easier by many hands. Even if you have never taken part in any
radio contest at all, find out whether any
of your local clubs are putting on a station for NFD this year and volunteer to go along and help out.
Many clubs and societies hold NFD planning meetings months before the event, so now is the time to find out if any
of your local clubs are planning an entry. If you cannot find one, then form your own group for NFD. Operating portable for 24 hours in early June is great fun!
NFD is a participative amateur radio operating event. It is designed not only
16
please mention AMATEUR RADIO when replying to any advertisement
MARCH 1985
CONTEST FORUM
as an HF contest which is taken seriously by many, but also as an operating and social amateur radio event which can be enjoyed by all club members. NFD is amateur radio at its best!
Top Band contests The RSGB organises four Top Band
(160 metre) contests each year. Three are on CW and one is on SSB. The contests are all of short duration. The CW contests start at 2100Z on the Saturday evening and run for just four hours through to 0100Z on the Sunday. A high level of activity is usually to be found on Top Band not only from UK stations, but also from many European and DX stations who make apoint of getting on the band to work the UK stations during these RSGB 1.8MHz contests.
The RSGB's Town and County Top Band Contest is on SSB and runs from 2100Z to 2400Z on a Saturday in March. The operating times are designed not only to be of convenient length, but also to be at a time of night when Top Band conditions are likely to be good for interG, European and also possibly for DX working.
this way the same postcode changes hands many times during the contest. It is not uncommon for astation to give you your own postcode back later in the contest. After it has been handed around between several stations, the original may well have become distorted.
The exchange of postcodes in ROPOCO is a simple form of message handling exercise; operating and logging accuracy is an important feature of ROPOCO. The postcode exchange makes awelcome change from the rather bland exchanges that have become commonplace in many contests. ROPO COs are held from 0800Z to 1000Z on two Sunday mornings during the year.
Region Round- up Region Round- up is another Sunday
morning inter- G CW contest run by the RSGB. Lasting for just 5hours from 07001200Z on the third Sunday in May, this contest runs on two bands together: 3.5 and 7MHz. Stations give their RSGB region ( 01-20) as part of the exchange. The multiplier ( max 40) is the total number of different regions worked on each of the two bands.
ROPOCOs The two ROPOCO contests organised
by the RSGB are very short ( they are only two hours long each) but they have a special twist to them! Rather than exchanging serial numbers and RST reports as is the case in many contests, in the ROPOCO contests the exchange is RST and a postcode.
The postcode sent in the first OSO is the operator's own postcode, but for the second and successive QS0s the postcode sent is the postcode that has just been received in the previous OSO. In
Low power contests Designed specifically for the QRP CW
enthusiast, the RSGB runs two low power contests during the year. The first is the Low Power Fixed Contest which is held
in two sessions on the third Sunday in April. The morning session is from 07001100Z and the second session in the afternoon is from 1300-1700Z. QS0s can be made on both 3.5 and 7MHz CW. Extra points are earned by contacting other ORP stations, but ORO stations can be worked too.
The second QRP event is the Low
Denis G3MXJ adjusting his homebrew six- band field- day special ATU, during 1984 NFD while operating as G4DAA/P. The author sits back and watches how its done.
Power Field Day held in July. Again this contest is in two sessions ( to allow a lunch break!) for the convenience of operators. The morning session is on 3.5MHz and the afternoon session is on 7MHz. CIRP field day operation is made very simple with modern rigs. The logistics required in getting on the air for afew hours during the Low Power Field Day Contest are very simple! Low Power Field Day is an opportunity to combine QRP operating with a summer's day in the fresh air!
Commonwealth Contest Still referred to by many as BERU
(British Empire Radio Union), the Commonwealth Contest is the RSGB's only major all- band HF international DX contest. Lasting just 24 hours it is designed for Commonwealth stations to work each other. Non- Commonwealth stations cannot take part.
From the UK the largest quantities of stations to be contacted are in Canada VE, Australia VK and New Zealand ZL. During any BERU there is always a sprinkling of activity from many of the rarer Commonwealth areas such as Jamaica 6Y5, Malta 9H1, Zambia 9J2, Gibraltar ZB2 and some of the Caribbean islands VP2M etc.
21MHz CW and 21/28MHz SSB These HF band contests are both just
12 hours long and are for G stations to contact as many stations and countries as possible anywhere outside the UK. The 21 CW contest held in October is a single- band event, whereas the 21/28 SSB contest covers two bands. In the years of good HF conditions these contests provide large numbers of QS0s but, as the sunspot cycle continues its dive to ever lower depths, the number of QS0s to be made in these contests diminishes rapidly.
7MHz CW/7MHz SSB Whatever the sunspots are doing,
there is nearly always plenty of activity
on 7MHz! These two single- band contests run for 21 hours each and are
designed for UK stations to work as many non- UK stations and DX countries as possible on the 7MHz band. The CW and SSB events are on different weekends.
During these contests UK stations can usually run strings of stations on 7MHz, because it is the UK stations that are sought after by the rest of the world. For overseas stations, contacts with UK stations are the only ones valid for the contest. RSGB 7MHz contests ( partic-
ularly the CW one) are very popular, not only with UK participants but also with overseas entrants.
IARU SSB Field Day The SSB Field Day held on the first full
weekend of September is an IARU
Region 1event. UK participation in this multi- national contest is looked after by
the RSGB. This is also apopular club and social event as well as a major HF SSB field day contest.
MARCH 1985
please mention AMATEUR RADIO when replying to any advertisement
17
CONTEST FORUM
SWL Contest
The 13/14th July 1985 has been chosen for the first of a new series of SWL contests organised by the RSGB. Fuller details will be published nearer the time, but the dates for this new SWL contest have been chosen to coincide with the IARU Radiosport Contest which is a major international DX contest for transmitting amateurs on both CW and SSB. Having an SWL contest on the same weekend as a major DX contest means that there will be no shortage of stations to log!
Cumulatives
As well as the HF contests described above, the RSGB also runs a series of cumulative activity contests at various times on 1.8, 3.5, 7and 28MHz. These are short operating periods aimed at giving newcomers to contesting and old-timers alike achance to make some contacts in acontest format, but without there being any strictly competitive element. Participation and operator training are important factors in the ever increasing popularity of HF cumulative contests.
Championship
The RSGB runs an annual HF contest championship table for both transmitting amateurs and for SWLs. These championships are designed to encourage participation by RSGB members.
RSGB contests are organised for the benéf it of RSGB members in the UK and for non- UK contest operators worldwide. UK entrants and operators in RSGB contests must be members of the RSGB.
Rules and results
The details given here are intended only as abroad outline of the RSGB's HF contest programme. Full details, rules and results are given every month in Radio Communication.
UK participants should note that, in order to avoid the unnecessary redistribution of large quantities of mail following every contest, the logs from UK members should always be sent directly to the adjudicator shown in the rules.
For overseas entrants only, there is now a separate address which can be used for all of the RSGB HF contests.
CA Worldwide 160
Don G3XTT, compiler of DX Diary and keen Top Band DXer has reminded me that ' serial numbers' are no longer given in the CQ Worldwide 160m contests. This was incorrectly stated in the potted version of the rules that appeared in the January issue of Amateur Radio.
Up until a few years ago, serial numbers were exchanged in the CO WW 160m contests ( as opposed to the CO Worldwide CW and SSB contests, where
as far back as the writer can remember, serial numbers have never been used). Don N4IN, the CO WW 160 adjudicator requests views from participants on whether serials should be used or not.
By the time that this is read the 1985 CQ Worldwide 160m Contest will be long over, and it is hoped that anyone who did take part for the first time as a result of
reading the write-up was not too confused when they found that no serial numbers were being exchanged!
The number of UK stations that get on the band during CQ WW 160 is quite high, but the number of log entries is low! Using a computer, Don N4IN analysed the 136,000 different loggings for last year's contests. This showed that 225 different Gs made QS0s during the CW leg of the contest and 186 Gs during the SSB leg. The number of logs received from G for the CW section was only 11! Don N4IN makes the plea that no matter
how small your score, please send in a log!
Send It In!
This is a plea that can be echoed for any contest! However small your contest
score, it is always worth sending it in to the organisers. The 17 HF contests organised by the RSGB provide plenty of opportunity for making many interesting contacts as well as improving HF operating techniques.
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£1.50
2 pole sub min. connectors ideal radio control RS
466/472/488/343 5pairs
£2.00
IDC CONNECTORS
25 WAY D PLG or SKT D37 PLUG 20-WAY SOCKET ( BBC USER PORT) 26-WAY SOCKET ( BBC PRINTER) 34-WAY SOCKET (BBC DISC DRIVE) 40-WAY SOCKET
ea £2.00 £1.00 £1.50 £2.00 £2.00
MADE UP DISC DRIVE CABLES
34 IDC TO 34 WAY CARD EDGE
SINGLE DRIVE £6
DOUBLE DRIVE £8
WIRE WOUND RESISTORS
W21 orsim2.5W10 OF ONE VALUE FOR
£1.00
1R0 2R0 2R73R9 5ROIOR 12R 15R 18R 2OR 27R 33R 36R
47R 12OR 18OR 200R 330R 39OR 47OR 560R 68OR 820R
910R 1K 1K15 1K2 1K3 1K5 1K8 2K4 2K7 3K3 10K
W22 or sim 6watt 7OF ONE VALUE for
£1.00
R22 1R5 9R1 1OR 12R 20R 33R 51R 56R 62R 12OR 180
270R 39OR 56OR 62OR 1K 1K2 2K2 3K3 3K9 10K
W23 or sim 9watt 6OF ONE VALUE for £ 1.00
R22 1R0 3R0 6R8 56R 62R 100R 220R 27OR 39OR 68OR
1K 1K8 10K
W24/ sim. 12 watt 4OF ONE VALUE for
£ 1.00
R50 2R0 1OR 18R 47R 68R 75R 82R 15OR 18OR 20OR
27OR 400R 62OR 82OR IK
PHOTO DEVICES
Slotted opto -switch OPCOA OPB815 2N5777 50p TI L81 TO18 Photo transistor TI L38 Infra red LED 2/50p
OP12252 Opto isolator Photo diode 50p MEL12 ( Photo darlington base n/c)
RPY58A LDR 50p ORP12 UDR
LEDs RED 3mm or 5mm 12/£1 GREEN or YELLOW 3or 5mm 10/£1 FLASHING RED 5mm 50p
£1.30 100/£25.00
£1.00 100/£16.00
50p 6/£2.00
50p 85p 100/C6.00 100/£6.50 100/£30.00
DIODES
1N4148 1S3740 Germanium 1N4004 or SD4 1A 300v
1N5401 3A 100V BA157 1A 400V Fast recovery BA159 1A 1000V Fast recovery
100/£1.50 100/£2.00 100/£3.00
10/£1.00 100/£2.50 100/£3.50
MULTI TURN PRESETS
1OR 2OR 100R 200R 500R
40p
2K 51( 22K 50K 100K 200K
IC SOCKETS
8- pin 12/£1; 14- pin 10/£1.00; 18/29- pin 7/£1: 100/£12; 1k/£50; 22/28- pin 25p; 24-pin 25p; 100/£20; 1k/£100: 40- pin 30p; 16- pin 12/£1; 100/£6
TRIMMER CAPACITORS small
GREY 1.5-6 4pF GREEN 2-22pF
5for 50p
GREY larger type 2-25pF
5for5Op
SOLID STATE RELAYS NEW 1OA 250v AC
Zero voltage switching
Control voltage 8-28v DC VARIAC 0to 130v 6A new uncased
£2.50 MOO (£2)
POLYESTER/POLYCARB CAPS
10n/15n/22n/33/47n/68n 10mm rad
100/£3.00
100N 250V radial 10mm 100/£3
1000/£25.00
1u5 P/carb 15mm rad
100/£7.00 (£ 1)
2u2 160v rad 22mm
100/£10.00 ( 121.50)
470n 250v AC X rated rad
4/£1.00
33n/47n 250v AC X rated rad 15mm
10/C1.00
10n 250v AC X rated rad 10mm
10/£1.00
100n 600V SPRAGUE axial 10/£1
100/£6.00
BEAD THERMISTORS
GLASS BEAD NTC Res iv 20 c 25OR 1K2 50K 220K 1M4 R53 THERMISTOR
80p £2.00
BEAD TANTALUM CAPS
6u8 25V 47u 3V 68u 6V 12/£1 2u2 20V 8/£1
1i0o0w/c£a6..0000
MONOLOTHIC CERAMIC CAPS
100N 50v 100/£6 10N 50V 470N 50v 100/£7 luF 50V
10N 50v di Ipackage 0.3" rad. £4/100
100/£3.00 100/C8.00
C30/1k
STEPPER MOTOR 4 PHASE 2
9v WINDINGS
£3.50
10/£30.00
KEYTRONICS
332 LEY STREET, ILFORD, ESSEX Shop open Mon-Sat 10am-2pm TELEPHONE: 01-553 1863
MIN ORDER £3.00
OFFICIAL ORDERS WELCOME
UNIVERSITIES COLLEGES SCHOOLS GOVT DEPARTMENTS
MIN. ACCOUNT ORDER £ 10
P&P AS SHOWN IN BRACKETS ( HEAVY ITEMS)
65p OTHERWISE ( LIGHT ITEMS)
ADD 15% VAT TO TOTAL
ELECTRONIC COMPONENTS BOUGHT FOR CASH
MARCH1985
please mention AMATEUR RADIO when replying to any advertisement
19
MARCO 'WADING
1985 CATALOGUE AVAILABLE - Many prices reduced - range increased - 123 pages Wily illustrated. Price 65p, per copy ( free upon request with orders over £5) includes 30p Credit Notes, special offer sheets, order form and pre- paid envelope. SENS NOW FOR YOUR COPY.
UMMIUMIM
LSCO
280
LS01
280
LSO2
289
LSO3
289
LSO3
329
1506
280
1509
289
1510
289
LS11
289
LS12
259
LS13
339
1514
559
1515
259
LS20
289
LS21
289
1522
289
LS30
339
LS32
289
LS37
239
1.674
389
LS122
70p
15138
45p
15138
689
15151
759
LS155
50p
LS157
459
15158
58p
LS180
809
LS181 15182
70p 72p
LSI83
1110p
15166
1.95
LS170
1.75
LS244
1.00
15245
2.00
15257
73p
15383
1.15
MM:51Z11
4000 249 4021 59p
4001 24p 4022 011p 4002 259 4023 359 4007 259 4024 50p 4011 24p 4025 24p 4012 249 4027 46p 4013 50p 4028 459 4014 00p 4029 76p 4015 80p 4030 35p 4016 40p 4031 1.30
4017 009 4033 1.25 4018 00p 4034 1.40
4020 859 4035 700
TRANSISTORS DIODES
7V047
Pace MI
AC127
0.30
ACI28
0.30
AC128K
0.34
AC132
0.55
AC141
0.26
ACI41K
0.40
ACI42
0.26
AC142K
0.48
AC151
0.45
AC152
0.45
ACI76
0.28
AC176K AC187
0.40 0.42
AC187K
0.48
AC188
0.44
AC1881(
0.50
ACY40
0.88
40142
1.10
40143
1.10
40149
0.06
AD161
0.42
AD152
0.42
A0161/162 0.99
AF106
0.48
AF114
2.10
AF1I5
2.10
Anil;
2.10
AF1I7
2.10
AFI 18
0.88
AFI21
0.02
AF124
0.48
AFI25 AF1213
0.48 0.48
AF127
0.48
AF139
0.68
AF178
0.08
AF239
0.118
AF279S
0.75
AL100
2.50
AL102
5.90
AL113
2.20
ASY80
1.75
AU110
1.40
47102
4.32
BA102
0.34
BA110
0.67
BA121
0.40
BA129 54148
0.38 0.16
BA154
0.08
BA155
0.10
BA156
0.08
BA157
0.28
84164
0.14
881848
0.52
138105B
0.30
BB105G
0.40
BB11013
0.42
8C107
0.10
Aor B
0.12
Taw
ABorC BC113 BC114 BC115 BC118
BC117 BC118 BC119 BC125 130140
BC141 BC142 BCI43 BC147 AorB BCI48 AorB BC149 BCI57 50158 BCI59 BC160 BCI61 5016813
BC169C BCI70 BC170B BC171 BC171 AorB BC172 AorB BC177 BC178A BCI82 ABorC BCI821 ABorC BC183 ABorC 5C1831 ABorC BC184L ABorC BC207 BC208 BC212 ABorC BC2121 ABorC BC213 Aor5 BC213L AorB
BC237 BC238 BC239C
50251 ABorC BC301
Idea (0 0.10 0.12 0.14 0.12 0.12 0.15
0.22 0.17 0.30 0.12 0.28
0.42 0.30 0.30 0.08 0.10 o.oe 0.10 0.09 0.10 0.10 0.10 0.30 0.30 0.12
0.10 0.14 0.12 0.10 0.10 0.08 0.08 0.12 0.20 0.22 0.09 0.09 0.09 0.09 0.09 0.10 0.08 0.12 0.10 0.10 0.15 0.16 0.09 0.10 0.08 0.10 0.09 0.10 0.10 0.10
0.11 0.12 0.14
0.12 0.14 0.30
.171M.11111.111 400d1W Piashc 3V- 75V 8p each 10/759 13W Plastic 3V- 200V 15p each 10/t1.40 15W Flange 47-47V £1.26 each, 25W Plastic 75-75V 949 each 20W Stud 7.5-75V £ 1 35 each
guriizeint.Y.rtfralluirSIZEIMI
AN240P
3.42
AN2140
3.88
AN7150
2.90
1.75
CA403IP
2.88
CA4102
3.30
CA4250
3.50
CA4400 CA4422
2.98 3.07
107120
533
1C7130
5.26
107137
5.10
LM380N
1.65
LM1303N
2.52
HA115IP
3.12
MC1307P MC1310P
1.85 1.05
MC1312P
2.25
MC1327P
1.25
MCI330P 0.83
MC1349P MC1350P
1.85 1.20
MCI351P
2.50
MC1352P
1.50
MC1357P
2.88
MC1358P
1.30
MC14961
1.15
M12315 M12325
2.10 2.10
M12378
2.30
MRF475
2.50
MRF479
520
MRP477 10.00
NE555
0.50
C-rnos 555 14E556
0.88 0.80
5441024
5.35
SAA1025
8.40
SAS560A
2.50
SAS560S
I.85
SAS5705
1.00
SAS580
2.85
SAS590
2.82
SC9503P
1.10
S1432A
4.00
S1901B
5.20
S19175
7.25
5113270
1.10
51476003N 2.44
SN76013N 1.00
SN76023ND 2.90
SN76033N 2.46
SN76110N 1.12
SN 2611 5N SN76131N
2.00 1.05
SN762213ND 1.80
61476227N · 1.10
SN76530P 1.40
SN76533N SN76650N
1.60 1.06
SN76660N S14 75666N
0.75 0.80
511(015
0.50
TA7108P
3.20
747120P
2.20
TA7129AP 3.58
TA7130P
1.65
TA7172P
1.80
TA7193 TA7I72P
5.50 1.80
TA7I76
2.50
TA 7202P
4.15
TA7204P
1.843
TA7205AP TA7208P
1.50 3.27
TA7210P
0.50
TA7222P
2.12
TA7223P
3.88
TA7227P
5.60
1473104 - 1.80
TA7609P TA7611AP
4.28 2.88
TAA263 1443104
2.46 2.08
TAA550
0.50
TAA570
1.99
144611412 3.50
TAA630S TAA66113
3.90 1.70
14.4700
2.80
144840
3.38
140105
2.90
FM FILTER 1.20
TBA120 AS
S. SA S5 O. T. U. UO TBA12013
1.30 1.32 1.30
113A231
1.45
154281
2.06
TBA395
1.20
1544800
1.00
TBA400
2.30
184510
2.90
TBA5100
2.00
TBA520/C) 1.60
113A530/0 1.30
15A540/0 1.40
TBA550/0 1.52
TBA560C
1.70
TBA560C0 1.60
TBA570
1.30
713A641130 I 4.50
TBA673
2.40
TBA700
2.65
TBA750
2.80
154800
1.00
TBA810P
1.10
TBA810S
1.20
154820
1.60
TBA890
3.88
154920/0 3.00
TBA950/2A 3.05
TBA970
4.05
TBA990
1.88
TCA160C
3.90
TCA2705
4.00
TCA270SA 4.02
TCA800
3.10
TCA940
1.90
104440
3.80
TDA1002
1.90
TDA1003A 5.50
TDAICO6A 2.40
TDA1035S 4.50
TDAI044
4.30
TDA11705 3.00
TDA1190
3.50
TDA1200
2.98
TDA12700 3.70
TDAI327A 1.08
TDA1352A/13 1.58
TDA1412
1.20
TDA2032
2.80
TDA2020
4.00
TDA2030
2.78
TDA2140
5.90
1042521
4.10
TOA2523
3 30
1042530
2.70
TDA2540
3.80
TDA2541
3.80
TDA2560
3.50
TDA2571A 2.50
TDA2581
3.20
TDA2590
3.20
TDA2591
2.98
TDA2593
2.96
TDA2610
3.20
TDA2611A 1.94
TDA2640
2.90
TDA2680
3.40
1042690
3.50
TDA3950A/B 2.60
UPC554C
1.32
UPC557H 0.90
uPC566H 2.95
UP575C2
3.20
UPC1018C 1.10
yypa BC302
Prica(C) 0.32
BC307 BC308A BC323 8C327 80328
BC337 BC338
BC350 8C440 BC441 80461
BC547 BC548 BC549 BC550 BC550C 80557
BC558 BCX34 BCY70 BCY71
BCY72 BCZIO BCZ11 BDI24P FIC1309 I3D131
80132 50131/132 50135
2E;e
80134
80139 130140 130144 1313145
130150A 130159 130160 80165
130175 130182
50183 80184 80201 130202 130204 80222 130225 BD232 BD233 80234 130235 E10236 80237
00238 BD241 130243A
0.10 0.10 0.90 0.14 0.14
0.12 0.12
0.14 0.30 0.32 0.32
0.12 0.12 0.12 0.18 0.18 0.12
0.12 0.27 0.15 0.17
0.18 1.68 1.43 0.80 0.68 0.34
0.34 0.95 0.32 0.36 0.36 0.38
0.38 0.38 1.60 1.82
0.51 0.65 1.63 0.45
0.60 1.00
1.10 1.20 0.72 0.87 0.80 0.90 0.643 0.45 o.eo 0.62 0.63 0.63 0.65
0.56 0.00 0.410
UPCI025H 2.90 UPC1032H 0.90 UPC1156H 4.20 UPC1158H 0.70 UPC1115314 OAS
UPC1151H Leo UPC185H2 3.70 UPC1212C 1.30 UPC12251-1 0.04 UPC1230H 3.90 UPC1350C 4.20 UPC1367C 3.40 UPC1378H 4.40 UPC2092H 2.80
D Cif NNECTORS 9 15 25
ei,laut, MALE way way way
Solder 0751.00 1.50 402.00 240
Solder 1001 45 1.85 Angle 1502 00 240
COVERS 080080 0.80
Metal Co- ax Plug
0.19
Plastic Co-ax Plug
0.14
Metal Line Sockets
Single Juno
0.80
Socket
0.80
Plastic phono 0.10
F.M Plugs
0.20
P1.259 Plugs 0.38
Reducer
0.16
Low loss splitter 1in.
2out
1.00
25 Watt Iron corn.
Plete with steel and
plug attached 7.20
CS 18W. as above
7.00
Antes 15W iron 5.00
Antes 18W iron 5.00
Antes 25W iron 5.20
Antes elements
2.00
Antex bits
0.95
Antes stands 1.90
Soldersucker 4.50
nozzles
0.65
amp 12 way Same 12 way 10 amp 12 way 15 arnp 12 way 32 arnp 12 way
0.18 0.20 0.40 0.44 0.90
MARCO TRADING ( DEPT AR3)
The Mailings High Street Wem, Shropshire SY4 5EN
Tel: 0939 32763 Telex: 35565
Mme 802444 BD375 813410 50434 80436
BD437 BD438
130439 130507 80508 130509 80510 BD517 80520 50699 80707 EIDX18 BOX32 I3F115 5F117 BF119 BF120 BFI23 BF125 BF127
BF152 BFI54 BF157
BF158 BF159 BF160 BF167 BF173 13F177 8F178 BF179 BF180 BF181 13F182 BF183 13F18.1 BF185 BF194 BF195 BF196 BF197 BF198 BF199 BF200 BF222 BF224 BF224J BF240 BF241 BF244
13F244A OF244C BF245A
BF254 BF256 BF257
PNee IC) 0.65 0.32 0.76 0.68 0.68
0.76 0.75
0.68 0.48 0.53 0.54 0.443 0.56 0.66 1.25 0.88 2.35 2.10 0.32 0.54 0.82 0.38 0.40 0.42 0.38
0.16 0.23 0.40
0.22 0.24 0.23 0.30 0.25 0.42 0.30 0.32 0.35 0.35 0.32 0.32 0.32 0.32 0.04 0.10 0.10 0.10 0.14 0.16 0.26 0.48 0.20 0.16 0.20 0.20 0.26
0.28 0.24 0.28
0.15 0.40 0.32
2VP· Moo ft)
BF251)
0.30
5F259
0.32
5F262
0.30
BF263
0.30
BF270
0.30
BF271
0.20
5F273
0.18
BF274
0.32
8F323
0.92
BF336
0.20
BF337
0.211
BF338
0.20
BF355
0.42
BF363
0.82
8F367
0.24
BF37I
0.27
BF422
0.38
BF450
0.38
BF457
0.33
BF458
0.36
8F459
0.44
BFR39
0.22
BFR40
0.22
BFR41
0.22
BFR5I
0.30
BFR61
0.32
BFR62
0.25
BFRI311
0.34
BFR90
1.72
BFT41
0.38
BFT43
0.38
BFW10
0.79
BPN44
0.70
BFX29
0.28
BFX30
0.30
BFX80
3.54
BFX84
0.24
13F085
0.26
BFX136
0.26
BFX87
0.26
BFX89
0.65
BFY50
0.21
BFY5I
0.21
BFY52
0.21
BFY57
0.40
BFY90
0.90
BFY90.3
1.34
139103
0.20
59101
0.44
139103
0.58
81104443
1.70
89739
0.30
139156
0.42
BRY61
0.001
EISS17
0.541
135527
0.92
BSX19
0.34
BS X20
0.34
BSX59
0.52
55X76
0.29
51100A/02 0.94
Prim (C)
S 101/300 1.95
BT101/500 1.25
131102/300 1.35
BT102/500 1.65
81108
1.50
137108
1.30
BT109
1.10
BT116
1.25
51119
3.02
51120
3.00
81121
3.02
131138/600 1.30
51151/5608 0.90
BT151/300R 1.15
13T179/4009 2.80
BU100A
BU104
2.00
BU105
1.20
BUI05/02
1.56
BUI08
1.80
BU124
1.75
BU126
1.25
BU133
1.80
BU204
1.35
BU205
1.30
BU206
1.70
BU2O8
1.55
BU208A
1.63
BU208/02 2.05
5U3265
1.75
BU407
1.65
BU4070
1.80
BUX80 BUY20
3.70 1.75
BUY69A
2.00
BUY695
1.08
BUY101
0.48
131118
1.10
131122
0.68
137125
0.12
57127
0.10
57133
0.10
131135
0.25
131164
0.44
81179
0.66
131152
0.87
131154
0.40
131187
0.72
131159
4.75
81196
0.44
81199
0.47
81206
0.24
131207
0.24
131210/400 0.25
131210/603 0.26
81210/500 0.30
57233
1.20
81227
0.26
131229
0.30
81238
0.88
81)(10
0.24
7>me
Pace (C)
57036/150 0.22
EWX36/600 0.28
137048/300 0.72
BYX49/300 0.47
BYX55/350 0.29
BYX55/600 0.33
BYX71/600 1.18
134712
0.42
C106D
0.80
E1222
0.40
E5024
0.30
061873
0.45
11144
0.04
I112052
0.11
ME0402
0.20
ME0404/2 0.24
MEU21
0.60
MJ400
1.25
MJ2955
0.90
MJ30130
1.98
MJE240
0.00
MJE340
0.64
MJE370
0.88
MJE520
0.46
MJE2955
0.111
MJE3055
0.70
MPSLO1
0.28
MRF475
240
MRF479
5.20
64RP
10.00
0447
0.10
0490
0.08
0491
0.00
0A95
0.18
04200
0.011
04252
0.15
0025
2.10
0026
1.70
0C28
1.60
0029
2.47
0C35
1.76
0036
1.76
0042
0.72
0C42K
1.40
0C44
0.72
0045
0.88
0071
0.80
0072
0.82
0051
0.88
00200
2.48
00202
2.20
ORP12
0.85
13200613
1.80
1120105
1.62
SHG1 5
0.40
TAG1/100 1.40
TAG3/403 1.71
11044
0.40
11045
0.48
11046
0.48
TIC47
0.70
IIer06A
TIP304 TIP31C TIP32 TIP32C T1P33A TIP3AA TIP41C
TIP42A T1P47 T1P110 11P2955 TIP3055 11543 11088 11S90 11591 ZTX108 IT0109 ITX212
N4001 N4003 144004
144006 N4007
N4148 N5400 N5402 N5405 N5406 145408 0820 214697 2N706A 2142904 2N2906 2N2926G 283053 2N3054 2143055 2143702 2143754
2143708 2143772 2143773
2N3904 2N3906 2N5294 2N6107 2146126 2SB337 25C495 2501172Y 2501173Y 2501302 2501226
2501279 2501306 2501307
2SCI413A 25C1444
rir11711 11 11 , 1Z.B.111 Ef32:1;81a5111M
SIU LIIMETEI4 SPE 1Al
ussian
6+ · .1 eel · ·
FUU. RANGE OF SONY TV VIDEO SPARES
Attractive
p ices
on
22 "
DC Volls1.2Yelr. 1. 2. 3. 12. 3(160 600 C Volts: 3. 6. 15, 80, 150. 300. MX
00 900
remote con rol T.V. sets DC Cum. M/A 000 0.6. 6. CO, 803, 3000
VIDEO HEADS SLC6-SLC7 A/676-293-8A SLC5 A-676-204-4A
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/4W pack10 each value E12 - 10R to 1M 610 pieces
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G3OSS TESTS
A en -29. 1
PM MMT 44,28980 Attar 10d8 50n
eeponee 2. 1.85 II - 20. Delon
-39. 1
-4g. 1
-59. I
-79. 1
-129. 1 DAN»
Ref Inc
28. 00MHz 2. COMHz
2. 00MHz/dly 10ee /d1y
Fig 1Receiver response
Re. be rlOgHf V d be ' 25kHi'
A dge
MM MMT 144.289 40. RESPONSE
3
-14.0
Atten 10d8 50n
TG - 20. Odge
-24. C
-34. 0
-44. 0
-54. 0
-64 : 0
-74. 0
-94.0
-94. 0
-104. 0
-114.0 OP*I>g
ge , 145. 00mHt 2. 00MHz
2. 00MHz. di y Rea b.
10re
id b,
Fig 2 Transmitter response
000H,
A dB O.
-10. 0
pál MM MM T 144,2ge
Atten
50n
29 PEP
2/1, 85
TC - 10 Odgro,
Cal 1broted
-20. 3
-30. 0
-40. 0
-50. 0
-70. 0
-90.0
-102. 0 0Agg>
Ref 144. 99980MHz
Inc
2. 00kHz
2gd 2. 000Hz 01 v 10. 8,44:
MOeí.d bbee
Fig 3 2W two-tone intermod
without any apparent performance degradation, which is excellent.
Subjective trials Iused an early sample at the beginning
of January and obtained some extremely good reports, some stations stating that the transmissions were about as narrow as they have heard on 2m, even though I was running the transverter at no more than 1.5W into my Dressler linear, again underrun to produce just 100W PEP output. After the transverter had warmed up I did not seem to have any drift problems, although when underrunning the transverter, which obviously meant driving it well below the ALC threshold, I did notice that the power output reduced a little with time.
It was so amazingly convenient to be able to set the input gain to give the required output, and if Iwanted to use the rig at higher power for ' barefoot' testing Ijust took out a20dB attenuator which then caused the rig to go into ALC and produce the full rated output. This was said to be cleaner than average by those who reported on my transmissions.
The receive noise figure was easily good enough for all normal uses and Idid not note any particular input intermodulation problem developing, unless I switched in my muTek masthead preamp. Even then, Ionly experienced slight troubles when very strong stations were on the band. However, the general band noise this winter has, unfortunately, been far worse than Ihave ever known it before; thermostat, computer and Christmas tree light switching interferences running riot with the band!
Stability The receiver seemed to be stable and
the lower gain of the new model is very much an advantage as it reduces any possibility of overloading the main HF receiver. Even so, Iam slightly puzzled about the gain distribution of the new transverter, for there is some padding in between the front end and the mixer which should not really be necessary.
It was useful to have the repeater shift facility, although Idid not use it on the band as my TS830 does not have an FM capability, which is actually agood thing in the context of optimum performance on SSB and OW. Idid not note any spurii within the band, but with the masthead pre- amp switched on Istill noted slight
intermodulation wash produced by the Euston Tower digital transmissions from below the band, although this virtually disappeared when the muTek pre- amp was switched off. This is a very significant improvement over the performance of the old transverter which produced so
much wash from the same source, even when no masthead was on, especially when I beamed across Euston. This clearly indicates a very clear improvement in the RFIM distortion.
Laboratory tests
We checked the receiver input noise
figure to be around 2.2dB using aRohde
and Schwarz SKTU meter, although this
figure could be at least 0.25dB in error.
The GaAsFET has, therefore, no signifi-
cant advantage over a device such as
BF981. Personally, Ido not quite approve
of the use of GaAsFETs for specmanship
purposes, but such is life! The input
intercept point, however, is far better
than that of the old model, but even so I
feel that it could have been appreciably
better using virtually the same compo-
nents much more carefully matched,
with perhaps a slightly different circuit
around them.
The overall gain is reduced from
around 30dB in the old model to 21dB in
the new one and this is agreat advantage
to avoid receiver overload. We plotted
the Rx passband using a tracking
generator with a spectrum analyser
together with a mixing technique.
Figure 1shows that the peak gain is
just under 29MHz output frequency, and
at band edges the gain is reduced by an
average of 2.5dB, which is not of too
much consequence.
Note that at 140/24MHz the response is
12dB down, whilst at 150/34MHz the
response is around 18dB down. This is a
narrower response than that of the old
transverter but Iwould have preferred an
even more rapid fall- off outside the
band.
No
serious
anomalous
breakthroughs were noted on the 28MHz
output.
We undertook many tests on the
transmitter side and found that the input
sensitivity was very high indeed, full
output being reached with well below
-6dBm input with the preset drive level
appropriately adjusted. The RF sensing
was extremely sensitive, the rig going
over to Tx for an input level well below
1mW. Nevertheless, I strongly recom-
mend the use of the PTT line which stops the transverter from continually switching between Tx and Rx whilst the main rig is on Tx.
Figure 2 is a plot of the 28MHz to 144MHz low level response, the input preset being adjusted for an output level of around 40mW, a level chosen to be miles below any possible ALC threshold. As there are far more tuned circuits the response can be seen to be much sharper, which is all to the good, but at band edges the fall- off was just 3dB average, which is reasonable enough.
Harmonics We had agood look for the presence of
harmonics and other output sprogs. I have to emphasise here that the review sample was a prototype but, even so, I was a little disappointed with the harmonics suppression which was not as good as Imight have expected. We also noted the 5th harmonic of the input drive present on the output, 28.2MHz producing 141MHz at around - 63dB ref 25W.
Another sprog at 147.4MHz baffled me at first until John and I put on our thinking caps, calculating the - 56dB carrier to be twice the LO, minus three times the input frequency. This may be quite a low level, but it is slap in the middle of the Police band! If this is amplified by a linear, the output level could actually be at around 1mW if the main output were at 400W peak. At least one has the advantage that the sprog would be horizontally polarised while the Police use vertical polarisation. It is worth watching and the explanation might sort out aproblem here and there!
The 116MHz breakthrough on the output was totally insignificant and no 28MHz breakthrough was noted. The. worst harmonic was the 3rd at - 45dB
which might irritate somebody on 70cm but, in fact, Iam more concerned that the 2nd, 4th and 5th need to be alittle better.
We plotted many two tone intermodulation tests, again using the new spectrum analyser. The signal sources were two Marconi 2019 generators mixing in ahybrid with its output feeding
directly into the transverter. We used drive levels of up to OdBm
(1mW) and set the input drive preset appropriately. The two tone plot for 2W PEP (Figure 3) can be seen to be superb, the transverter performance probably being better than any 28MHz drive
22
please mention AMATEUR RADIO when replying to any advertisement
MARCH 1985
G3OSS TESTS
A de
MM 4,417 144, 208
O. 0 _Atur 404:6 5041
106 PEP 2. 1.85 7G - 10. OdBe Ce:1,ctor.
-20.0 _
-40.0 _
-50. 0
-60- 0
-70. 0
-BO. 0
-00. 0
-100.0 7.4:>T7
44 , : 45. 0000,447 .0. 04442
:O. Ohm, da
Fig 4 10W two-tone interned
Pe· d. 330
A dB 0.0
MM IT 144/2541 MY PEP 2,1/05
Atten 5003 50.
TG - 10. 0011..
U
-20. 0
-30.0
-40. 0
-50. 0
-00.
-70. 0
-50. 0
-90. 0
-100. 0 CAW/
Ref 144. 913960$0.4 1. ,c Z. 00····
2. COdflidl v Rea ·· [TOO 14, I · . 01. 414 be Trm
Flg 5 25W two-tone intermod
I de. El. 4
o4f4 NP , : 44,200 3. Attar, 50413 50,
. 65 :II. Ode.
Tc:im ,cted
1!
Ref : 44. 99135CP, 2. 001·14,
7: 2. 0014·44 0. P
Fig 6 27W two-tone intermod
.0 Iii
would be other than that produced by a modified Trio TS830 or 530. Do not forget that a two tone test gives results which are the worst possible indicators and under normal speech drive IPs would be somewhat lower.
It was at around this drive level that reports were obtained which were
extremely complimentary about the transmission. One station using a bomb proof receiver ( 10251E with muTek front end) incorporating a narrow 1.8KHz IF filter, commented that Iwas occupying no more than around 4.5KHz bandwidth, including that of his filter. It can thus be seen that, in effect, the combination was not producing any significant products at
all outside the transmitted IF passband. We then took two plots at the 10W PEP
level, one with 10KHz spacing between carriers and the other with 1KHz spacing. The 10KHz spaced plot, Figure 4, shows the 3rd order IPs to be well down, and very significantly better than the performance of the old model. A 20W PEP plot gave 3rd order products of - 31.5dB
average, so we went even higher up to 25W PEP. Figure 5 shows the performance from two carriers spaced 1KHz
apart, the 3rd order performance still being relatively good. Orders between 5th arid 9th show reasonably good attenuation but higher orders still do come up a bit, although they are at
reasonably low levels. Again, in practice, higher orders should be well down on speech.
The final plot, Figure 6, shows the two tone performance with the rig driven hard into ALC, thus showing the worst possible performance. The 3rd order products are not too bad, and higher
order products can be seen not to fall down as fast as they did at lower levels. My conclusion regarding all these plots is that Iwould prefer to see the rig set up
for 20W PEP for the onset of ALC, but 25W PEP is not too bad provided the drive itself is clean.
The entire set-up will need to be very carefully adjusted if the transverter is to feed alinear, and the best way to do this
is to set the input drive with asaturated
signal from the main rig so that you are at least 8dB into ALC. You should then adjust the ALC preset very carefully indeed to back off the output down to perhaps the 5W PEP level for driving most Iinears.
My colleague, Jonathan, developed a neat little computer program to measure
output power and frequency versus time, taking measurements every 15 seconds or so in 10 minute runs. Each of these runs was interspersed with 3 minute cool- off periods. The basic transversion frequency accuracy was well within 1KHz, and once the whole rig had
warmed up and settled down, the average error was around 100Hz for lower output drive levels, but up to 400Hz when delivering full power. The frequency drift noted is perfectly reasonable for FM and, of course, the duty cycle of SSB would keep drift much lower. On AMTOR, though, you might need to watch drift and twitch the main transceiver a little until everything had warmed up and stabilised.
At full power, output power drift was minimal, the ALC holding it up extremely well. At lower levels though ( le 5W carrier) the gain drifted by up to 2dB in a 10 minute period. If one wanted to use lower power regularly but keep the maximum power constant, the measurement shows that it is again highly advisable to use the ALC internal preset rather than back off the input gain to take the rig well below the ALC threshold.
Alignment Microwave Modules should be detail-
ing user alignment in their instruction book, but they strongly advise that other presets should not be touched, for any maladjustment could cause chaos, so you will have to be very, very careful to twiddle the right one! Note that there is another preset for adjusting the thresholds of the power indicators and this should not be touched.
Two separate crystal oscillators are provided with switching for repeater use, and the 600KHz offset was accurate to around 500Hz. There could, of course, be considerable variations between crystals, so you may need to watch this, together with any heat drift susceptibility.
The current drawn when transmitting a 25W carrier was 5.7A, and Irecommend. that you use agood power supply. Ihave heard so many badly regulated ones with ripple on them which are better suited for driving light bulbs. A first-class power supply is a must in a shack and do not underestimate its importance, particularly if the same supply is running other equipment, which might include alinear, at the same time. Always go for asupply that has acapability of delivering around 50% more current than you think you may need, for inevitably you will want to add on various bits and pieces which you might not think about at first.
All our tests were carried out at 13.8V stabilised, but the transverter should
MARCH 1985
please mention AMATEUR RADIO when replying to any advertisement
23
G3OSS TESTS
work satisfactorily from dc inputs over quite a range from, say, 12V up to 14.5V, although the manufacturers state that not more than 13.8V should be used. In actual use on the bands Ireceived no reports of any frequency pulling on transients, even though the actual voltage being delivered to the transverter was probably varying several hundred mV in my normal set-up because of leads and switches. In the lab tests the voltage was held very steady.
Conclusions This product had been rumoured for
around 18 months and Ivery much looked forward to reviewing it. It is obviously far better than the old one but, frankly, it needed to be, for competition is now entering the field. MM were right to give it a higher power capability and this is just about right for average requirements. Both the transmit and receive
section showed significant performance improvements but it is in the ergonomics that Ifeel that the advantages are of great importance.
There is still one problem which this new model has not fixed and that is that there is no ALC feed to go back to the
main exciter, which would have gilded the lily. The provision of an ALC internal loop, however, with careful adjustment
of the input drive level, will allow you to work the mic gain on the main rig sensibly, thus keeping the exciter drive
clean, even if you lift your voice abit. We checked the ALC loop time constant to be many seconds long, and this is again
excellent as its operation would be almost unnoticeable in practice. Ihave not seen the new instruction book yet as it is in the course of preparation.
Ifeel that this is the best product that Microwave Modules have introduced for many years. I highly recommend its
purchase, although it is a lot more expensive than the older model. I understand that both will run in parallel for awhile until market forces dictate the possible demise of the old version. The transverter should suit virtually all purposes but it does fall short of the ideal just a little. There is likely to be some competition though, in a few months time, and then the choice will be controlled by cost, and Ido consider that this new model is quite reasonably priced considering its much higher power capability and better overall performance than the old model.
Thanks The price tag of £215 includes VAT. I
would like to take this opportunity of thanking Microwave Modules for their
co-operation, and Jonathan Honeyball and Myles Capstick for helping me make all the measurements.
ICOM IC551: A LOOK AT
In 1977, Ifirst became interested in the potential of 50MHz receiving with a simple Microwave Modules converter, and using a 13 element horizontal log periodic beam which covers the frequency range 50 to 500MHz.
During 1979, the peak year for sunspot activity, Ienjoyed very many crossband
OSOs between 10 and 6 metres with stations all over the Americas and in
some other continents. I can well remember one particularly startling contact with VE1ASJ in which Istill received him on 6m when he had reduced power to only 10mW.
It seems possible that this low power
OSO was a record for the lowest power across the band, although Ifeel sure that it could easily be repeated at the next sunspot maximum.
STARTING ON 50MHz
By application Iapplied for one of the first forty 6m
licences but was not granted one apparently because the DTI did not want to licence anyone in a large urban area, but having re- applied in 1984 I was delighted to be one of the new licensees from November.
Many of the 6m licence- holders have built their own transverters, but just as many have purchased a commercial rig
in order to get on the band quickly. As the band has not previously been allocated in the UK hardly any rigs are available here, but Thanet had already taken the decision to import the 10551 in readiness for the next batch of licensees, and kindly supplied one to me for review.
Ifirst started my transmissions on the band using a little Kenwood-Trio rig,
TS660, with 10W capability on FM, CW, SSB and AM. This rig covers 21, 24, 28 to 29.7 and the whole of the 6m band and is a
delight to use as it is simple and reasonably effective. However, its receive performance is not particularly outstanding, the IF filter characteristics
being its main let down as it is very wide well down the skirts.
IC551 When the 10551 arrived Iwas very keen
to put it on the air and try it out. Immediately Irealised that the Trio was incapable of receiving many of the weak signals that the Icom coped with reasonably well. The 551 ( basic cost £ 495 including VAT) has fairly similar facilities to the 251 ( now discontinued) and is frankly quite an old model which may soon be superseded. The basic version only includes OW, SSB and AM; an FM board (£ 126.39 including VAT) being an optional extra which nobody seems to want! The smoothly rotating VFO knob
covers the whole band from 50 to 54MHz in either 100Hz or 1KHz steps ( 5or 50KHz
per rotation). Facilities included in the basic model
are: two VF0s, three memories, memory
scan and programme frequency scan (between frequencies stored in memory
2and 3), squelch working on all modes, RF and AF gains mounted coaxially, passband tuning ( optional extra £ 110.60 including VAT) and VOX control on
mic/OW ( optional extra £ 54.95 including VAT). In addition, levers switch in: RIT,
noise blanker, AGO fast/slow, frequency lock and VOX on/off and Rx/Tx.
Mic gain and compressor threshold with on/off are also provided on rotary pots. A 4- pin mic connector is fitted
24
please mention AMATEUR RADIO when replying to any advertisement
MARCH 1985
-70dBm
G3OSS TESTS
-115
-85
-125
-777
f
loom IC551 AGC action fast, pen speed 250mm/S, paper speed lOmm/S
-70d Bm -100
-115
-fts"
-115
--
Icom IC551 AGC action slow , pen speed 200mm ,S paper speed 10mm/S
which, therefore, does not allow for amic to control frequency. A headphone jack is fitted on the front panel, and the frequency readout is the usual green digital display in 100Hz increments. Mode status is also indicated on the display.
A bug hutch cover opens up on the top panel to expose six presets: scan speed, CW delay, CW monitor level, anti- VOX level, VOX gain and VOX delay. The rig is supplied to operate on 240V ac mains or 13V dc inputs. The antenna socket is an S0239, an earthed wing nut also being provided.
An accessory socket has 24 pins, including facilities for: squelch operation detection, 13V dc output switched (max 0.3A), external PTT control, Rx audio fixed output level, mic amp audio output, 8V/5mA on Tx only, ALC input and a ground connection. The connections are on pins 1to 8inclusive, the remainder of the pins being unconnected.
The loudspeaker is on the underneath of the chassis, and the front includes a bail stand which, when lifted, allows the audio to be reflected forwards from the table under the rig. Additional interconnections on the back include: external speaker, scope, Ax antenna breakpoint in/out and a3.5mm CW keyjack.
Laboratory tests The RF input sensitivity of the 10551
measured very well and is certainly good enough for even the quietest locations under normal conditions, although I
noted avery slight improvement when I switched in the very low noise pre- amp on the Lunar Electronics linear which I obtained direct from California. The RF intercept point was acceptable but not particularly good for distance spacings, but close into the carrier it degraded by around 8dB due to the wide first IF roofing filter.
The latter is one of those unfortunate facts of life if arig has to incorporate an FM facility, even if this is not actually fitted. Whilst at the moment there is not too much ORM on the band, one day we will undoubtedly need every bit of selectivity and freedom from blocking that we will be able to obtain.
The IF selectivity measured extremely well down to - 40dB but the 60dB selectivity showed that the skirt did widen quite noticeably. The S- meter covered a range of 20dB from Si to S9, which is not really enough, and the scale above S9 gave from 11 to 16dB for each indicated 20dB step.
AGC charts The product detector distortion mea-
sured well, and audio quality was quite good. Maximum audio power was just about enough for normal purposes but I would have liked a little more in hand. Fast AGC was very fast indeed and there was plenty of IF gain so that even low level signals were brought up to quite a high audio level. The slow AGC chart showed that full recovery took around 3 seconds, which is just about right for me.
The recovery for weaker signal changes was somewhat longer, however, but this seems quite usual these days.
The audio response fell very rapidly below 400Hz with PBT either not fitted or
adjusted centrally when fitted. There was clearly some HF attenuation in the audio output partly due to the effect of the IF filter, and 2KHz was some 4dB down, whilst 2.5KHz measured 6.5dB down, the IF filter cutting very steeply above this frequency.
Ihave to say yet again that Ido wish we
could have a flat passband with the response being controlled entirely by
the IF filter, but Icorn seem to think
otherwise on almost all their rigs. We applied our usual two tone tests to
the transmitter section, injecting appropriate frequencies into the mic socket with the rig's output interconnected with the analyser via an attenuator dummy load. At the 10W PEP level the intermodulation products were at a very low level (Figure 1), but there was
evidently some third order distortion cancellation between the PA stage and its driver, for fifth order was actually worse than third! We also noted some audio distortion within the IF passband
produced from the two tones. We managed to get 20W PEP out of the
rig after much pushing and shoving, and
the IPs can be seen in Figure 2to have deteriorated dramatically, showing that
it is advisable to limit the rig's output to 10W by altering the internal ALC threshold control.
MARCH 1985
please mention AMATEUR RADIO when replying to any advertisement
25
G3OSS TESTS
A cltion 4. 0
IC 551 1011 PEP 2 TONE 600/2600 Hz 21/12/84
Att.'., 5048 50p
TG - 10. Odern
- 16. 0 -28. 0
-46. 0
iigt 0 -66. 0
-76. 0
1
-86. 0
04>>>
Ref 'lc
50. 10055MHz 2. 013Idlz
2. 00.1z/di 1 e / d1v
IMIEq R.. R.
Yid be
B7Hz
Fig 1 10W two-tone intermod
A dB..
1[551/Lunar 6M10. 120P 12511pep 21/12/84
15. 1 . Atten 5018 50n
TG - 10. Odge Col ¡ teat.,
5. 1
-14. -24. 9 -34. 9
-54. g
-64. g
-74. 9
-84. 9 DAD»
-Ref Inc
50. 20092MHz 2. 00kHz
2. 00MHz)dly 1004m. / di:
Res b. pum-9
Vid by 350Hz
Fig 3 125W two-tone intermod
e den,
7. 5
IC 551 2012 PEP 2 TONE 600/2600 Hz 21/12/84
Attie, 501/3 50o
TG - 10. Odge
:a; 1prated
-13. 0
-23. 0
-33. 0
-43. 0
-53. 0
-63. 0
-73. 0
-83. 0
-93. 0 OAD»
Ref Ire
53. 10055MHz 2. 000Hz
2. 001.Hz/d, y Rea by 1 e / di: Vid
F7g 220W two-tone intermod
Hr 87T,
A dB, 20.0
10.0
[551/Lunar 6M10. 120P 180Wpop 21/12,64
Atten 5018 50p
73 - 10. OdElen
Ca; 1brcte
O. 0
-10. 0
-20. 0
-30. 0
-40. 0
-50. 0
-60. 0
-70. 0
-80. 0 Cep>
Ref Inc
50. 20092MHz 2. 000,4z
2. 00kHz;d1y 100me / di,
Re. b. 300 Hz Vid b. 350Hz
Fig 4 160W two-tone intermod
Fig 5 AF/RF trancever response
A den 0. 0
·
-10. 0
IC551 TX AF/RF Reeponee Ht 1W 21/12/84
_Att.,, 3018 50p
TO - 20.018m
-20. 0
-30. 0
-40. 0
-50. 0
-60. 0
-70. 0
-80. 0
-90. 0
-100. 0 0AbDt.
Ref Inc
50. 20000MHz 1. 001,112
1. 000Hz, d E -2717. , al:
Uos V. 303 ,..
Vic, b.
22Hz
Since some amateurs are driving
linears with the rig, which require only 10W input for full output, it can be seen
that there is a danger of overdriving if one does not watch peak power very carefully. Internal presets can adjust both minimum and maximum power levels and these most certainly need readjustment if you install the PBT and
VOX options. For the reader's interest, Ialso include
Figures 3and 4which show the overall two tone performance with the 551 driving the Lunar Electronics 6M10.120P solid-state linear. This is rated at 125W PEP output, but can deliver more than this at the expense of ghastly IPs. The 125W PEP level is about as hard as I would like to drive it, but how about third order products averaging at - 13dB when the Lunar is provoked to give 160W!
By using a fairly cunning test procedure, we managed to obtain acomplete
plot of the overall response from the mic input to the SSB carrier output, setting levels very carefully so that the maximum power never exceeded 1W carrier
(Figure 5). This ensured that the plot would not be affected by any ALC action.
Note that the position of the carrier is
offset to the left of centre by 1KHz, as we were still learning to drive the equipment at the time!
The LSB rejection is 40dB at worst, the carrier breakthrough below - 42dB, whilst the IF passband can be seen to slope down above 1KHz, which makes transmissions alittle muffled well before
it reaches the beginning of the real filter action. It is fascinating that arejection of 60dB can be noted at 3.3KHz above the carrier, which is actually alot better than we noted on Rx, which is puzzling. By 4KHz the response can be seen to be down to around - 80dB which is excellent.
Note that the lower sideband does
show some noise breakthrough, which is not present on the USB. It is clear that
the transmit IF passband is, in effect, narrower than the receive one, as any effective widening of a filter due to reciprocal mixing problems will only occur if the'noisy mixer' is before, rather
than after, the filter, hence the inferior
Rx IF shape. We had a good look at the harmonic
and sprog output of the Tx section. Second, third, fourth and fifth harmonics were all below - 80dB which should please the DTI, the carrier level being set at 10W. There were, however, three sprogs at 45.052MHz (- 76.8dB), 45.005MHz (- 72.5dB) and at 55.348MHz (-72.7dB). I only mention these for academic interest as Idon't think they should disturb anybody.
We then drove the rig into the Lunar
Electronics linear to a level of 100W carrier, and noted the second harmonic from the linear output to be at - 57dB which is not really good enough as it is slap in the middle of band 2. Very considerable attention will have to be paid to second harmonic rejection from 50MHz if we are all to be given the band,
so watch it! The maximum power on OW was
measured at 13W, and the frequency accuracy on Tx showed amaximum error of 40Hz. On Rx the SSB frequency error reference carrier was - 150Hz, whilst OW was 800Hz high. lcom's policy, though, is to offset OW anyway, thus explaining part of the apparent error.
Subjective trials I enjoyed using this rig very much
indeed on the band, and in practice Idid
find it necessary to control the power output level very carefully indeed to avoid spreading when using the Lunar linear. Transmit quality was said to be adequate, although HF lacked a little clarity. Transmissions were alittle on the thin side, and this confirms the results of the frequency plot. Idid not notice any drifting, and there did not seem to be any
spurious receiving problems, although there was some interference from the strongest television carriers until the wretched things were finally turned off in the first week of January.
I found the rig very easy to use, although Ipersonally still prefer to use a transverter with my main station rig, a Trio TS830. Just before writing this
review, Thanet very kindly sent the passband tuning and VOX control options. The PBT greatly helps in OW reception and life without the VOX unit was incredibly tiresome on OW, since I had to use the VOX switch all the time.
The VOX accessory is therefore almost vital if you are to take OW seriously on the band, which Ithink is amust anyway. However, Ifound the VOX unit caused severe degradation to the audio quality, for it includes a bucket brigade time delay of around 50mS which cannot be switched out, even with VOX off.
This delay causes brain congestion if you are either monitoring your own transmission or you are working duplex, for the echo of your own voice may well jam you up! Even OW is delayed by the
same amount, and it would thus be impossible to use the equipment for AMTOR it the VOX unit is fitted. Without the unit, transmitted audio distortion was
26
please mention AMATEUR RADIO when replying to any advertisement
MARCH 1985
G3OSS TESTS
ICOM IC551 LABORATORY RESULTS
RECEIVER TESTS
Sensitivity, SSB ( level required to give 12dB Sinad)
Selectivity, SSB
3dB bandwidth
6dB bandwidth
40dB bandwidth
60dB bandwidth
-125dBm ( 0.125mV) 2.0KHz 2.2KHz 3.2KHz
5.5KHz
Product detector distortion at - 80dBm
1.1%
AGC threshold for - 3dB audio level ref high level
-110dBm ( 0.7m.V)
Calculated intercept point at 100/200KHz spaced carriers
-12.5dBm ( 52mV)
Close in ( 20/40KHz spaced carriers) intercept point deteriorating to -20dBm ( 22mV)
Maximum audio power ( 10% THD)
8 ohms; 4 ohms:
1.8W 2.7W
TRANSMITTER TESTS Maximum power output on CW Maximum attainable PEP power on SSB Carrier suppression ref 10W Worst LSB breakthrough
13W 20W 52dB -40dB
Weight 6.6Kg Size 111mm(H) x241mm(W) x31mm(D)
acceptable, but stations reported to me that with the unit fitted my modulation was very rough, spikey and harsh, even
with the compressor switched off. The PBT unit includes the compressor,
and if you want to alter output power with this unit fitted, you cannot without the compressor being in. The compressor seemed to produce, in combination with the bucket brigade gadget, very rough background noise, and advancing the compressor/power control more than 1/4
way severely reduced readability, which was harshly criticised.
As fitted, minimum power was 4W PEP and it would be necessary to readjust the
internal presets if you want this to go down to 1W. After extremely careful adjustment, and having accepted the
dreadful harshness caused by the VOX unit, compression did improve readabil-
ity for DX quite dramatically, so probably the PBT unit is agood buy. However, you should only buy the VOX unit if you absolutely must have VOX operation on OW. Alternatively, you might choose to dig into the circuit and modify it so that when VOX is switched off, the entire unit is bypassed.
Incidentally, this novel VOX circuitry did produce very effective VOX operation on speech, better than most others
that Ihave encountered, but Ipersonally cannot abide any add-on that severely degrades speech quality for normal contacts. Iam most disappointed that lcom do not provide any OW filter option for the set, an omission which is all too common these days.
Conclusions The price of the rig is very high indeed,
but you get some very good performance for your money. The IC551 is by no means the most economic way of getting on the band, but those who own them have, in the main, made many of the best DX contacts. It is useful to have a separate rig for the band in order to make cross band contacts with HF much simpler, and so Iconclude by giving a good recommendation if you can stomach the price.
I must applaud Thanet for at least making the rig available as astock item, and Ican just imagine the rush for rigs when the DTI are finally convinced that the band should be opened for all class A licensees. At the moment, Ihave heard that the problem is primarily some minor objections from Ireland, Belgium and France, but one by one other countries are being allocated the band on a restricted basis ( eg Norway). Let's hope we all have the band soon.
Thanks to Jonathan Honeyball and Myles Capstick ( G4RCE), to the 50MHz fraternity for all the assistance in preparing this review, and to Thanet Electronics for the loan of the review sample.
13cm UPDATE: EME 1325
VALVE LINEAR
Irecently reviewed in this magazine the SSB Products 13cm transverter and solid-state PA. The set-up gave a maximum output of just over 3W,
although the importers explain that newer devices should bring the solidstate linear output up to 4W. I have already had many good DX contacts on the band running just 3W PEP up the coax, which worked out at roughly 1W into the dish. My next step was to add the EME valve PA to the system, and replace the turning loop of UR67 cable between
the dish and the Andrews LDF 550 with semi- flexible Andrews FSJ450A.
As now installed, the complete set-up produces amaximum power of 25W PEP out of the transmitter, and around 15W into the dish. Of course, this is a very substantial power increase which made a dramatic difference to the received. signal strengths of my transmissions. I
now find that on average, taking the power differential into account, 13cm signal paths are not more than an S- point or two down on 23cm signals under normal conditions, but of course almost anything can happen in atropoduct.
Problems Ifelt that in this article Imight usefully
tell readers about the problems we had getting the linear to work, for we certainly did have a lot of trouble to begin with.
When the linear was first installed, with
MARCH 1985
please mention AMATEUR RADIO when replying to any advertisement
27
a3CX100A5 valve in it, we could get no more than 5W output for 3W in, and this was a bitter disappointment. The input SWR was well nigh perfect, the standing current and maximum anode current seemed to be about right, but we just could not suck out the RF into the load. The rig was returned to the importers who tried several other valves of the same type, all of which proved to give a very low RF output.
At this stage, Idiscussed the matter with Dr Charles Suckling G3WDG. We discussed 13cm cavities and valve types for quite awhile, and he kindly loaned me some 2C39BA valves to see if they would give better results. All four were checked with a low level drive and their gains varied from around 10dB to 13dB, the best one giving 12.5W output for around 500mW input. We then applied the drive from the SSB Products solidstate linear, and after some tuning up we heard adisturbingly loud bang just as the power reached 25W!
We had originally decided to try 1250V dc and after investigation we discovered that this voltage jumped over the anode supply decoupling capacitor, causing the anode supply feed blocking resistor to burn out in a few mS. We tried to replace this resistor with another one, taking more care with the loading, but again a loud bang blew the resistor, so we decided to reduce the anode supply volts to 1KV. Having again replaced the resistor all seemed to be fine until we tried pushing the system a bit harder, when there was yet another bang and this time the fuse went but not the resistor ( or so we thought). We again tried, being much more careful, and eventually produced a good 25W ( measured with the EME power meter reviewed recently) and the system seemed to work fine.
Flash! Bang! Wallop! Ihad amost exciting contact at 5/9 both
ways with a station in south-east Belgium, but afew minutes later on hearing a German station calling CO, disaster struck again. My wife, Fiona, was in the shack, and shouted, ' Turn off, turn off quick', as Istarted calling the station. I could already hear frying noises but Fiona explained that the entire linear amplifier was lighting up like a firecracker, and she could see lots of little lights moving rapidly inside behind the protection mesh. Some of these brilliant meteors were actually coming through the mesh.
Ihad to choose between my strong desire to make my first DL contact and my concern for imminent disaster, and
this decision was made all the more difficult when the DL actually returned
and called ' QRZ G30--'. Itried just once more but abrilliant flash caused immediate QRT!
Upon investigation we discovered that the anode feed replacement resistor had been burning steadily, and had a cold resistance of around 0.5Mohm, and obviously HT was trying to jump over it, through it or around it with somewhat alarming results. This was replaced with
alarge hairy wire wound, and the rig has worked successfully ever since, although I admit to being somewhat nervous about attempting any reloading!
It is quite clear from these spectacular happenings that we should never have attempted 1.25KV, but it was worth trying! Iam assured, by many who know the valves intimately, that it is better to work them at higher HT voltages with lower
currents for optimum linearity, but it seems that EME's special capacitor is inadequate so they will need to have a look at this in their design.
I have discussed the valve problem with many 13cm band enthusiasts, and whilst one amateur may swear by his 3CX100A5, another feels that the 2C39BA is the best thing since sliced bread, so
the situation needed resolving. It seems
that the anode capacities of the two valves are quite different, and the lower capacity of the 2C39BA thus requires a larger cavity to tune it properly. Imust then theorise that the EME anode cavity, which they advertise as being compatible with 2C39BAs, is clearly slightly too large for the other valves, including the
7289. Some amateurs who have made their own cavities may well find that they suit the 3CX100A5 perfectly well, but then they will be too small for the 2C39BA.
This may well be the root of a discussion point which has been aired for months. We did note that maximum output from the original 3CX100A5 was
obtained with the tuning control hard up
one way, and this would seem to be quite a good indicator that the cavity was incompatible, but if anyone has got other viable theories Ihope they will write to
the Editor to express their views. As far as Iam concerned Ishall keep to the valve recommended by EME but, unfortunately, they are extremely difficult to obtain at any reasonable price: Ihave actually been quoted around £65 for a brand new one, and there do not seem to be any government surplus ones around.
The linear is supplied with the bias circuit board, cooling fan, cavities and complete input and output circuits, and the importers ( Piper Communications) can supply suitable HT transformers. The circuit includes input trimmers for adjusting input SWR, frequency tuning for the input cavity and output loading and tuning for the anode cavity.
The brass cavities are highly polished internally, then plated with a 5 micron silver layer. Input and output connections are on N- type sockets and the bias control allows the standing current to be
adjusted from cut-off to well over the required 50mA or so. It is recommended that the equipment should peak at no more than 150mA, but under maximum drive conditions my own one actually takes slightly more: around 165mA.
The fan is designed to cool both the anode and cathode cavities, and having set the heater voltage at 5.6V on transmit and 6.0V on receive, Ifound very much less power drift than I might have expected. Many amateurs have found it necessary to retune their 13cm cavities continually, but Ihave not had to touch mine for weeks, for every time Icheck the power it is between 20 and 25W on keydown after three or four seconds.
The cavities are turned to athickness of 5mm out of high quality brass. The bypass capacitors are made from polished brass isólated with 0.25mm Teflon foils. We all felt that the construction was to a very high standard and so my only real point of criticism is of the rather dodgy Teflon dielectric capacitors.
Conclusions The availability of this linear has
brought many people on to the band with extremely good signals, and it may well be responsible for much 13cm activity in Europe. Ithink it will be a long time before we see any reliable high power solid-state linears, mainly because of the colossal price of PA devices, and so this EME linear has become very popular for the band, and can therefore be strongly recommended.
Despite the fact that there is obviously a considerable amount of compression on peaks at full power, the actual intermodulation products, judging by comments from other amateurs, seem to be reasonably low, and this appears to be one of the strange phenomena of this type of valve used on microwave. A good valve should give around 15W output from 1W drive and such a power on the band should produce extremely good results. However, cable losses are far more severe on this band than on any lower frequency so to make it worthwhile to run such a linear in your shack rather than put the entire transverter and solidstate PA at masthead, you will have to invest in extremely high quality co- ax, especially if there is arun of more than a few metres.
With the latest SSB Products gear at the masthead, you could get 4W into the dish and even with only just over 2dB loss in 23 metres of co- ax at vast expense, I am only achieving one S- point advantage, so there is a lot to be said for keeping everything solid-state at masthead, especially if you need along cable run.
The cost of the linear, including fan but excluding valve, is £218.00 including VAT, with HT transformer costing around £34.00 including VAT extra.
Many thanks to Dave Aram of Piper Communications for his tremendous help and co-operation in assisting me in the preparation of this review.
28
please mention AMATEUR RADIO when replying to any advertisement
MARCH 1985
I-- SHORT WAVE LISTENER
TREVOR MORGAN GW4OXB
With the Amateur Radio
prefix award now well under
way, some readers may be
thinking that a great deal of
time is necessary to be able to
qualify and, depending on
their own circumstances, may
believe that the number of
prefixes required would be
difficult to obtain given the
time available.
As an experiment, Idecided
to see just what could be
heard by someone with
extremely limited time avail-
able for listening. Iknow it's
taking things to the extreme,
perhaps, but I allocated
myself 30 minutes in each
session with one session a
day over aweek. However, as
it was Christmas week, Itook
two sessions on the Sunday
before Christmas to make up
for the ' lost' day.
The table shows date, time
of listening period and the
prefixes heard. To qualify as a
'contact' it is necessary to
have heard the station
claimed, ie if the station is
calling you can claim it, but if
the callsign of the station is
mentioned during ' handover'
but you cannot actually hear
it, you do not claim the prefix.
No cheating please!
Looking at the table you will
note that there is a distinct
absence of a lot of the ' easy'
ones ( particularly the Rus-
sians who didn't seem to be
around at the times Iwanted
them to lift the score ... typi-
cal!). One annoying factor
was the number of nets on air
who passed between stations
without acallsign being given
at all which wasted a lot of
time ( the Americans were the
worst on this score).
Ithink this shows that even
with
conditions
being
adverse ( time of year, low
sunspot period) and given
only very limited time, agood
score can still be made. Bet
there were a lot more around
that Ididn't hear too!
Nevertheless, I see no
reason why we should not
have a good response to the
award scheme and I look
forward to receiving your
claims.
The contest season is here
and hooking on to acouple of
contest operators can net some good prefixes.
So, now for something completely different.
Educational project
During November, Ihad the
pleasure of working with fel-
low members of the Swansea
Radio Amateur Constructors
Club at an event set up by the
Swansea
Maritime
and
Industrial Museum. The idea
was to present amateur radio
to local schoolchildren as
part of an educational pro-
ject. Many local schools took
up the offer and sent children
to the museum by coach to
see the exhibition and see the
radio station in action.
The project was held over a
week and we were on air
using the call GB2MEP.
Despite bad propagation
conditions, we had an inter-
esting week and were sur-
prised by the interest shown
in the station by youngsters
from the age of only 10
years .... especially the girls!
There are two reasons for
mentioning the project.
Firstly, the success of the
station has resulted in a
number of enquiries, not from
radio enthusiasts but from
local schools asking us to put
on demonstrations of the use
of amateur radio, including
short
wave
listening.
Secondly, afew days after the
event we received a very
unusual piece of SWL repor-
ting that certainly deserves
mentioning.
The report, from Nick Bain-
bridge in Glasgow, not only gave us asignal report for one contact but agraph giving us comparison reports of our signals as received over a period. As aresult of this fine piece of reporting, Nick not only received the requested QSL card but the club chairman and the members presented Nick with the ' Gower Award' for his excellent effort.
Of course, the average amateur would not expect to receive such areport but for a special event station it is a useful observation.
A lot of schools have science projects that could be enhanced by ademonstration of amateur radio and/or short wave listening and the experience gained is very useful to the operators as well as the students. Why not try your local school?
Complaining bitterly I noticed in one of our
companion magazines that some short wave listeners are complaining bitterly about non- receipt of replies to their reports.
Conversely, amateurs are complaining about the terrible standards of cards they are receiving. Not, Iadd, from listeners, but from licensed amateurs after acard for their DXCC or other award. 1have often mentioned the importance of accurate and useful reporting but it appears that
not only listeners are guilty of bad reports. One amateur complained that a QSL card received not only got the callsign of the contacted station wrong but had the frequency incorrect, the time incorrect and gave a ' 5 x 9 both ways' signal report which, considering the location of the sender, was a virtual impossiblity!
It appears that if a card is wanted for an award claim some people think that just any old thing will do. This sort of reporting is not only useless but an insult to the intelligence of the station operator.
Listen to the QS0 and report anything unusual in the transmissions, any variations in signal strength or audio quality. If there is a station from the same area on an adjacent frequency, is his signal better or worse?
What about the distance? Is the station closer to you than he is to his contact? Remember, the operator knows he can be heard in the area of his contact so a report from that region would be pointless. Also, unless he is using a directional antenna ( or propagation is a bit wierd at the time) he can be reasonably sure that he can be heard within a radius of his station equal to the distance between himself and his con-
tact. However, if he is using a
5- element multibander and you can give an accurate
23.12.84
0730-0800
80m Cil DA1 OJO DJ5 DL9 DM7 EA1 EA7 F6 ON7 TK5 YU3 WB1 WB3
FD1 G3 HKO KB8
23.12.84
1730-1800
20m EA7 GW4 GD4 KB2 KA1 PA3 W2 W3 WA1 40m EA8 18 UB5
24.12.84
1345-1415
20m DF4 F6 GW4 GI4 HA4 HK4 15
OH8 OK9 P11 SM5 SM3 SP3 SP4 WB1 WB2 ZB2 9M2
18 JB4 UB4 UB5
KB9 KC3 0E6 OH6 VO1 W1 W2 W8
26.12.84 27.12.84
1610-1640 1640-1710
20m DL6 G4 GW4 PA3 PY4 YU3 ZS2 5N3 6W1 W2 20m DL8 DJ2 ED4 GW4 K2 KC7 N6 V2 W3 WA2 ZB3 ZS1
28.12.84
0725-0755
20m CT1 CT5 EA8 EA7 EA9 G4 1T9 JA4 JA3 JB7 LZ1 PY2
4X4 9H1
80m AE8 DL8 DJO DF4 EA8 G2 CW3 NF4 Y57 -
Total time involved: 3hours
Total prefixes: 85
MARCH 1985
please mention AMATEUR RADIO when replying to any advertisement
29
SWL
report off the ' back end' of his
beam, he may be interested. Funny thing is that wire
antennae seem to have pecu-
liarities that are not covered by the theoretical diagrams to be seen in the textbooks. For
instance, my G5RV is set up with, theoretically, the main lobes of the radiated signal to
the east and west. However I get consistently good ' 5 x 9' reports from the North and particularly good reports from mobile stations using vertical whips. Any genius out
there with an answer to that
one? The G-QRP Club have their
spring QRP CW activity weekend over the 16/17 March, and their late spring SSB activity weekend over
the 4/5 May. The QRP boys are always keen to hear how far their signals are getting so if you want a bit of achallenge tune in to the QRP calling
frequencies below. The G-QRP members can
be heard around these frequencies at any time but the activity periods are a good time to try your arm ( perhaps that should be ears?).
Well, that's it for another month. Next time we will be
looking at the multiband version of the 'Dipole of Delight' and a new RTTY program for
the Spectrum computer, as well as some points of interest from the many letters received from readers. Until then, keep listening and good luck with the DX. 73, Trevor.
QRP calling frequencies
Times
CW QRG
0900-1100 1100-1300 1300-1400 1400-1700 1700-1900 1900-2100
2100-2300
14060, 21060, 28060 3560, 7030 10106 14060, 21060, 28060
3560, 7030 14060 3560, 7030
SSB QRG
14285, 21285, 28885 3690, 7090
14285, 21285, 28885 3690, 7090 14285 3690, 7090
NEW FOR
-it-ADMI
errls_Allm- à ihe
·
1985
MUM
erfix.Inari
lot 14, weir. ··1······. irk · mow. · arid ·mbur tolga
1.······
_
AMATEUR RADIO HF PREFIX AWARD (TWO-WAY AND SWL)
To qualify for an award you have to have worked/heard and logged
250 prefixes for the Bronze award 500 prefixes for the Silver award 1000 prefixes for the Gold award
The opening date is 1January 1985 and further details are available in SOIL (page 37)
AMATEUR RADIO MICROWAVE AWARD
To qualify for an award on one of these bands you have to fulfil each category
144MHz Bronze Silver Gold
Countries 7 14 21
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Squares 20 40 60
Distance 500 Km 800 Km 1200 Km
432 MHz Bronze Silver
Gold
5
15
10
15
15
25
40
400 Km
30
600 Km
45
900 Km
1296MHz Bronze Silver Gold
3
10
6
15
9
20
10
300 Km
20
500 Km
30
700 Km
The opening date is 1January 1985 and further details are available in On the Beam (page 44)
KEEP IN TUNE WITH AMATEUR RADIO AND THE AMATEUR RADIO AWARDS
Start working towards your chosen award now , All winners will receive free certificates- and find their names in Amateur Radio Magazine
(worth it for that alone). All entries or queries should be sent to Trevor Morgan GW40X13. Glen Ross G8MWR or Amateur Radio
GOING GOING
GONE!
Selling your rig can be fast, easy and painless when you use the services of G3RCQ ELECTRONICS. We advertise BIG in all the magazines, our turnover of equipment is fast, this means we can offer the BEST PART EXCHANGE deal and the BEST CASH DEAL. Our advertising is there to heolp you sell your used equipment without delay. REMEMBER if you are selling USED EQUIPMENT -- Contact G3RCO. Tel ( 040-24) 55733.
AUCTION
Auction your surplus equipment from the comfort of your own home! HOW? Let's say you have an XYZ rig for disposal and you value it at £ 150 you send me 10% (£15) for inclusion into the auction, plus FREE entry into LIST-A- RIG your estimated price of £ 150 will not be quoted so you may even receive bids over and above what you expect. There are no further charges. If your rig does not sell within 2month s ( that's two auctions) your 10% fee will be returned in full.
NATIONAL ADVERTISING FREE
Iwill advertise nationally in all monthly magazines on arotation basis lists of items to be auctioned. Potential purchasers will be invited to submit their bids by post to me before aspecified date ( auctions are monthly). All bids will be forwarded to you the seller. It is then up to you to contact the bidder of your choice and conduct the sale.
LIST-A-RIG
Imagine adata base which is constantly being updated and contains items for sale or wanted the list encompasses Dealers and Readers adverts. LIST-A- RIG is sent FREE upon receipt of aS.A.E. To include your own advert the fee is £2for TWO MONTHS ADVERTISING.
A FAIR DEAL IS MY POLICY
When you deal with G3RCO you get a straight deal. A full no quibble guarantee, coupled with free advice covering 25 years of Amateur Radio.
BUY lit TRY
If you buy arig from me you have one month to change your mind! If during the first month of purchase you decide that you have made amistake or you simply cannot get on with the rig Iwill allow you 90% in part exchange for another rig of equal or greater value, if you want cash back without another rig Iwill give you 80% of your purchase price.
MARCH AUCTION (Equipment may be sold by private treaty).
ICOM IC2KL LINEAR SEARCH 92M FM RECEIVER
ICOM IC 740 HF TRANCEIVER YAESU FP700 20AMP PSU TV CAMERA & MONITOR
TECH TE2OD SIGNAL GENERATOR FDK MULTI 2000 MULTIMODE YEASU FT757GX HF TRANSCEIVER
KW 2000B HF TRANSCEIVER HF TRAP DIAPOLE WITH FEEDER SX200 N SCANNER WELZ SP15 SWR/POWER METER ADVANCE VALVE VOLTEMETER AMTOR AMT 1AS NEW BOXED DATONG PC- 1GEN/COV 2M CONV.
TANDY TRS80, MONITOR, CASSETTE
TRIO 2500 2M HANDHELD
STANDARD C146 2M HANDIE
ICOM BASE MIC, IC SM6 QM70 2M LINEAR AMPLIFIER ALENCO 70CMS LINEAR ICOM AT500 ANTENNA TUNER YAESU FT1101 & 1012D & 277ZD TRIO TS 530S
h If you are interested in purchasing any of the above please send your bids to the address below.
ICOM 720A + PS15 PSU MM 144/50S & MM432/30L TRIO 9130 AS NEW 2MONTHS OLD YAESU FT720RU 70CMS FM KW204 TRANSMITTER TRIO 201A AND SPEAKER 2M FM
YEASU FT 480R TRIO SIG GENERATOR SG-402
Send S.A.E. today for current Ilat and full Information LOSER> EGRUIPINIENT CENTRE, GaRCICI ELECTRONICS
OS, CECIL. * VENUE, I-ICIRNICHILJRCH, ESSEX
TELEHONE HORNCHURCH ( 040-24) 55733
Please leave a message on the answer phone 73's de DAVE & CORAL G3RCQ & G4RCQ.
VISA
30
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MARCH 1985
BEGINNERS'
A few months ago Ihad along letter of complaint from areader about an article I wrote in an amateur radio magazine. It was not about the technical content of the article, nor about the style of prose, but centred upon his inability to get hold of some of the major components required for the project in the article. The writer was even kind enough to send me alist of his missing items and aspace under each one to name suppliers. I managed to fill the spaces in about 5 minutes.
In some cases Idid not have enough room to write in the three or four suppliers of an item. He seemed to assume that I had some mysterious source of supply of components not made available to lesser mortals when, in. fact, Ihad no more access to sources than him or anyone else.
Idid venture to suggest to him that part of the enjoyment of home construction of equipment is finding the cheapest possible supplier of the components required.
Problem Failure to locate specific items does
seem to be aproblem for the beginner in electronic construction or, worse still, failure to find the items at a reasonable cost. The problem is not the major barrier that many assume and, with a little prethought and planning, most projects can be built at reasonable cost without scouring the whole world to find all the bits and pieces.
If you do not mind paying high prices the problem quickly disappears, but I would like to suggest ways in which components can be found with an eye to the total cost.
Gone are the days when the market was flooded with government surplus items, all of which contained useful bits for the budding constructor. The few boxes in the corner of a shed which would yield everything the radio constructor was likely to require are now, sadly, athing of the past.
However, I believe it is easier and cheaper to obtain useful components than it ever was in the past. It might not be possible to have lots of surplus junk casually strewn about the place from which to cull required components, but it is very possible to keep and maintain a basic stock of items to reduce the problem and expense of buying in components for every project.
A few simple rules Try to avoid getting into the situation
where all the components for aparticular project have to be bought together. This is where the 'basic stock' idea comes into play. The wary constructor can have in his stock most of the ' bread and butter' components which occur commonly in projects.
The real buying, and parting with hard earned money, can be left to the supply
WORKSHOP
A series for the would-be constructor PART TWO: GETTING THE BITS
Rev George Dobbs G3RJV
A BASIC LIST OF USEFUL COMPONENTS
Resistors Capacitors
Variable capacitors Potentiometers Trimmer capacitors Semiconductors Diodes General Hardware
There are several very commonly used values, 100K, 10K, 1K, 47K etc, but the only real answer is to have all of the E12 series of preferred values from 1OR to 1M in 1/4 or 1/2 watt resistors.
The stock could be almost endless but certain types are used very frequently. Perhaps most common of all are the RF decoupling values: 0.1µF, 0.01µF, 0.02µF, 0.0mF in about that order of usefulness. Electrolytic capacitors can be expensive, so if prices seem cheap, get them. The commonest seem to be: 10, 100, 220, 2.2, 22 and 50i.LF in about that order. Silver mica capacitors for RF work are also very expensive, so buy when cheap, especially: 100, 560, 27, 39, 68, 330, 270, 10, 470, 18, 47, 56, 180, 750pF etc in that sort of order. Polystyrene capacitors make good substitutes for silver mica types in tuned circuits and are cheaper, the same values as above are common.
These can be financial killers! The airspaced variable if bought new will cost you an arm and a leg. See them cheap -- buy them. Values very often required are 10, 25, 50, 75, 100, 500pF.
10K and 5K log and 1K, 5K, 10K and 50K lin types seem to be commonly required.
3-60pF, 2-20pF and 100pF are common.
A little minefield, so many types are used, but if common types come up cheaply buy them.
Always have some general purpose silicon diodes in stock ( 1N914 or similar) and a selection of zener diodes ( 9.1V, 6.8V, 8.2V, 5.6V are common). Get some cheap red LED indicators.
Icollect various coil formers, 3/16 inch diameter being my favourite type, ferrite type, ferrite beads, cheap RF chokes, and usually keep in some Amidon iron dust cores.
This is where the basic stock really comes into its own! This stuff costs the earth. Any seasoned constructor will tell you that cases, knobs and switches can cost more than the entire electronics inside the box. Buy it when it's cheap -- old cases can be fitted with new fronts; cheap knobs, if there are a few matching ones at low cost; switches, especially miniature toggle switches; afew wafer switches (look for 3 pole 4way, 4 pole 3way, 2 pole 6way and 1pole 12 way); moving coil meters, the little cheap ex- tape recorder or CB equipment ones are very useful. Slow motion drives for tuning controls can be difficult and expensive to find, look for the little epicyclic, in line, reduction drives. Plug sockets, fuseholders, indicator lamps, in fact any of the stuff that goes onto front or back panels is worth buying when the price is right.
of more specialist items, such as particular semiconductors, inductors etc, required for the project in hand. It should be possible to dip into the stock to find 80% of the components for most projects.
Never begin a project until you have obtained, or at least located, all the required components. That spells frustration.
Become a hoarder of stuff and buy common components in reasonable numbers when the price is right. The
next time you want seven 0.01p.F capacitors they will probably cost five times more than you paid for the last lot.
Shop around; ask your wife about that, or, if you are awife, remember how you buy shampoo. The differences in price between various suppliers in electronic
components can be truly amazing. Like anywise purchaser of anything, study the market.
Now to expand a few of those rules. What are the best 'basic stock' items? These are the components used most
MARCH 1985
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31
BEGINNERS WORKSHOP
frequently in radio construction. The experienced constructors will know these anyway. One of the ways in which the less experienced constructor can
find them out is to read as many radio construction articles as he can lay his hands upon and see which items come up over and over again in circuits.
The table is my attempt at alist of items which seem to occur commonly in many radio projects. This is a very subjective list based upon my own needs as a constructor of mainly HF band equipment. This list is not exclusive but having most of these items would be a good starting point for a would-be constructor.
So much for what might be required ...but where can it be bought? The first piece of advice is to avoid, if at all possible, the plush component shop or the mail order companies with a glossy expensive catalogue. We pay for these worldly trappings. Leave them for items
that cannot be found elsewhere. The friendly corner junk shop has all but disappeared but it has been replaced with, Ibelieve, abetter phenomena-- the amateur radio rally.
Radio rallies All radio amateurs should know about
radio rallies: they are the meetings of hobbyists and traders held throughout the summer in locations up and down the country. Check the amateur radio press for events local to you.
All the big boys turn up with their sumptuous stands of far eastern grey and black boxes ready to take our cheques and card numbers, but we are only interested in the traders in the dirty jumpers with one or two stalls of small
items. I buy at least 75% of all the components Iuse at such events and Ido not attend very many -- unfortunately they are usually on a Sunday.
The whole event can be great fun. Try to get rid of the wife and kids; trailing around after a constructor hunting for
components is a real pain in the neck. If time allows do aonce- around the stalls before buying: the prices vary a lot and the next tent or room may have it cheaper. However, if a bargain price is attached to an item that seems to be in short supply on the stall then get it before someone else.
The untidy small stalls are often cheaper than the smartly laid out stalls. It is easy to forget what has been bought and often components are poorly or mysteriously marked, so carry a pen. A few small paper bags are useful too in case the trader puts it all into one bag. Individually bagged and marked components are much easier to sort out at the end.
The sort out at the end is perhaps the best part of the day. Ihave spent many happy Sunday evenings sifting through the bargains of the day bought at rallies.
Live in some remote spot? No rallies within range? Well all is not lost because there are a number of reasonable mail order companies which offer compo-
Some useful smaller mail order companies
Marco Trading, The Matlings, High Street, Wem, Shropshire, SY4 5EN. Tel: ( 0939) 32763. Very good prices on basic components like resistors and capacitors. Catalogue 65p inc postage.
JBirkett, 25 The Strait, Lincoln, LN2 1JF. Tel: ( 0522) 20767. John Birkett is my favourite component trader, good range, good prices. Issues lists which do not do justice to his wide ranging stock.
BCD Electronic Services, 200 Hessle Road, Hull, HU3 3BE. Tel: ( 0482) 225437. Good range with interesting list of semiconductors and ICs.
ACE Mailtronix Ltd, 3A Commercial St, Batley, W Yorks, WF17 5HJ. Good range, some good prices, catalogue at 30p.
Lightning Electronic Components, PO Box 8, Tamworth, Staffs. Tel: ( 0827) 65767. Good range, catalogue at 70p.
D S Electronics, 16 Eagle St, Hanley, Stoke-on-Trent, Staffs. Tel: ( 0782) 29898. Some interesting stuff in a useful catalogue.
Electrovalue, 28 St Jude's Road, Englefield Green, Egham, TW20 OHB. Tel: ( 0784) 33603. Wide range of components, good on ICs. Free illustrated catalogue.
Mintfordd Engineering, Sund Street, Ffestiniog, Gwynedd, LL41 4NE. Tel: ( 076676) 2572. 'Phil the box', who must be the cheapest place for cases and aluminium boxes. Every constructor ought to have his list of equipment cases and aluminium boxes.
The above list is far from exclusive but is merely afew of the traders Ihave used with satisfaction. Many others exist and are very good. Most issue some form of catalogue or list. Ihave stated prices where these are known. If in doubt send them something to cover the costs when asking for a list.
nents at good prices. The bigger boys in the field can be expensive and probably only ought to be used when other avenues have failed. Most radio maga-
zines have a host of medium and small
scale traders advertising in small column space. Many of these produce lists or
small catalogues and it is worth having a good range of such catalogues to be able to mail order shop around. I have included some names of companies in the table above.
One useful company Ihave used for
basic items, like resistors, is Marco Trading of Wem. They sell resistor kits of ten each of the whole E12 series at very reasonable cost. The problem with this is that although it initially sets up the constructor with his complete selection, these are not all used with the same
frequency. The less common values remain in good numbers when the
common values are all gone. Marco Trading also do avery good deal
in resistors if bought in quantities of 100.
Not very useful if these have to be all of one value but these can be made up of ten of any ten values, so the commonly used types can be replaced at reasonable cost. Other companies do similar
good deals; watch out for them. It can be very useful to buy some items
in bulk. Some radio clubs make up bulk orders of commonly used items which are shared out amongst interested members. Many small traders are pleased to quote aprice for components at 100 or more off of each value.
Hardware is none too easy to obtain cheaply by mail order but the small company Minffordd Engineering in Ffestiniog supply the cheapest equipment cases and boxes Ihave ever seen, and a good range of hardware, nuts and bolts. They will also make up cases and boxes to acustomer's own dimensions and drill and make holes in panels to order.
Storage Holding astock of components implies
that some storage space will be required.
Thankfully radio components these days are much smaller than they used to be and the majority of the basic stock could go into one reasonable sized drawer.
Istore resistors in cheap small buff envelopes bought at Woolworths. The value is written at the top of the envelope and they are filed in value order in ashoe
box. The same approach can be used for
smaller capacitors ( I also store my transistors in this manner).
My larger components are mainly stored in 2Kg margarine plastic boxes or 1 and 2 litre ice cream boxes. The compact plastic storage boxes which fit into racks are excellent for storage but are expensive. Ibought some from a
company that was winding up for avery good price.
Having matching boxes or cartons not only looks better but it also enables the containers to be stacked and stored in less space. Damp garages and sheds, although convenient, are not the best
32
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MARCH 1985
BEGINNERS' WORKSHOP
places to keep the components. Iknow more than one constructor who keeps his component store underneath aspare bed.
Try to be reasonably methodical and neat when storing components. Buying stuff and then just throwing the bags into adrawer may be convenient at the time but later an amazing amount of time can be wasted sifting through to find the desired items... which are in there somewhere'. It really is worth marking containers with accurate notices of their content. It is also worth, if time allows, grading and sorting out values to split up components of similar type.
The constructor who keeps every resistor in one big box, and some do, will spend almost as much time sorting out the components as building the project. Component gathering is no small part in building up electronic circuitry so make the task as easy as possible.
A simple project - an HF wavemeter
In the first article of this series I
advised the use of akit for the complete beginner to cut his teeth in construction. What follows here is a very simple but useful item for the radio station that can be built by anyone at low cost. The project also illustrates the principle of using cheap and cheerful components and adapting items to suit the pocket or their availability.
The wavemeter is not only useful to have around the shack but fulfills the legal requirement for aradio amateur to be able to check his transmissions for harmonic outputs. The circuit is shown in Figure 1.
Very simple - it is really just a crystal set with a meter taking the place of the headphones. Any schoolboy who can build a crystal set can build this wavemeter. The meter will indicate the presence of RF signals from 1.8MHz to well over 30MHz. There are two ranges to enable this frequency coverage.
The signals are received on apiece of pick-up wire and tuned by the tuned circuit C1/L1. Two germanium diodes form avoltage doubler detector circuit, a single capacitor provides RF decoupling and the output is indicated on the meter.
All of the components are simple and
Fig 1Circuit diagram and coil details
Lia Lib
cheap. The inductor ( posh word for a coil) is wound on a piece of 1/2in outer diameter plastic tubing. Anything of this
size would serve, but Ijust happened to find apiece of suitable tubing around the place.
The tuning capacitor is of the polycon' semi-airspaced type so common in the
cheap and nasty far eastern AM radios. This could be salvaged from an old nonworking AM set ... there are alot about, or it could be bought from one of the many suppliers who stock such items.
If the capacitor comes from an old radio it might be possible to salvage the two diodes from the same source. These should be germanium diodes, which are
usual in any detector circuits in radio sets. If your junk diodes come from old computer boards or industrial sources, then probably most of the diodes will be silicon, rather than germanium.
The meter is acheapie sold commonly by many amateur radio traders, originally designed for use in acassette recorder.
Almost any small moving coil meter would do the job, although the full scale deflection of the meter should be under 1mA. Meters around 500i1A are ideal, and the one Ifound seemed to have a full scale deflection of about 200µA. All of these are very common items, so look and scrounge around before laying down good money.
Values Ll -- see text S1 - change over toggle switch (small) Cl - 350pF polycon variable capacitor 01/2 - 0A81 or similar germanium diodes C2 - 0.021iF mica M - 5001.1A gr less moving coil meter
(see text)
Plastic case.- 2x4 1/4 x1 1/4 ins Knob/cursor - see text Terminal - for pick up
OY) ))) 0,)
Ll a
Lib
si (Low)
si Cl ( High)
DI & 02
Wind the coil
The first job is to wind the coil. This
requires 26swg enamelled wire. If you are winding a coil for the first time, the procedure is very simple.
Begin by anchoring the wire ( leave about 6in free) to the end of the former that will go to ' Si ( low)' in Figure 1. Secure it with sticky tape, then wind the wire along the former to make aneat coil, laying the turnings neatly side by side. This is called close winding. When 65 turns have been completed pull out enough wire to make a loop around 6mn long. Twist the wire in the loop until it is
MARCH 1985
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33
BEGINNERS' WORKSHOP
tight against the former. This is simply to
hold the tapping point between Ll aand Ll b. So the wire marked Si ( high)' on Figure 1 is, in fact, two wires twisted together.
That having been done, Ll bcan now be wound. This has only 6turns but they are
not close wound. They need to be spaced apart by about the diameter of the wire. This can be done neatly by winding the turns with another piece of 26swg wire alongside the winding wire. The extra piece of wire can be removed when the winding is completed. Alternatively, like me, you can just guess the spacing and
wind it with care. The end marked Cl in Figure 1must
now be secured with sticky tape. It is good practice to secure the complete winding and this may be done quite
easily by smearing the whole length of the coil with the clear glue sold for making plastic models. This is polystyrene cement and although I know others who buy all kinds of fancy
cements designed for the job it does work very well on coil windings and
seems to cause no electrical problems. The whole circuit is built up using point
to point wiring on the underside of the front panel on the case. Iused a plastic case, made Ibelieve by Vero, which I happened to have in stock. There are lots
of plastic cases to choose from and there is no reason why those so inclined could
not use awooden box.
Figure2shows how the circuit is wired up. The actual size of the case may well depend upon the available meter. Mount the variable capacitor, the switch and the meter in similar positions to those shown in Figure 2 and the wiring can begin around these components as anchor points. A slide type switch could be used for SW1 although Iusually avoid slide switches as experience has taught me that they can be prone to poor contacts, but they are much cheaper than toggle switches. The wiring follows the layout in Figure 2.
Calibration
Once the wavemeter is completed it requires calibration. A pointer knob and a cardboard scale could be used but I made up a perspex cursor which I attached to asuitable knob with Araldite. To give amore pleasing finish to the front panel I made a thin white cardboard front.
This was marked with rubdown lettering to indicate the scale and also the control functions.
It is possible to calibrate the wavemeter by checking the frequency of the tuned circuit at various points using adip meter but it is easier, and quicker, to use the wavemeter in conjunction with a transmitted signal to calibrate the scale. When the tuned circuit is aligned to the frequency of a transmitted signal the meter will show a peak reading.
The method of measuring this signal depends upon the amount of transmitter power, the length of the pick-up wire, how close the wire is to the signal source and the sensitivity of the meter.
It would be easy to be anuisance when calibrating the wavemeter by transmitting signals onto an amateur band just to calibrate the scale. The best method is to use low transmitter power and to feed it into adummy load via unscreened leads. The pick-up wire can be laid alongside these leads to receive the signals. Some experimentation will be required to sort out how long the pick-up lead will have to be and how close it must be placed to the leads on the dummy load.
The best technique for calibration is to transmit asignal into the load at aknown frequency and then look for apeak on the
appropriate range of the tuned circuit. Make a small faint pencil mark at each calibration point, then remove the knob and cursor and make up the scale by hand or with rubdown numbers.
My prototype has markings for 1.8, 3.5 and 7KHz on the low range and 10, 14, 21,
28 and 30MHz on the high range. A high
level of accuracy is not required as the harmonics are a long way from the
fundamental frequencies on the scales. The wavemeter is not an instrument for measuring frequency but for showing if there are outputs at undesirable fre-
quencies. The final touch is added by covering
the paper front panel with a layer of transparent plastic sticky- backed film to
add protection and a shiny finish. The wavemeter can now become part
of the shack instrumentation. Some further experimentation may be required to determine asuitable length and placement for the pick-up wire so that readings may be taken of actual transmitted signals.
The next article will discuss some other methods of electronic construction and describe a useful, but myste-
rious, item of shack equipment.
rNEWSAGENT ORDER FORM
ADIO To ( name of newsagent) Fore two_way r--ace enthusiasts Please order acopy of Amateur Radio for me every month NAME ADDRESS ·-
Newstrade distributors: Argus Press, Sales & Distribution Ltd, 12-18 Paul Street, London EC2A 4JS. ( Tel: 01-247-8233)
RTTY AND CW TRANSCEIVE WITH NO TERMINAL UNIT
This fantastic program interfaces direct with your rig. slashing the cost of previous systems. Split screen, type ahead, all the usual features and more. Tape and kit for the very simple interface, including PCB and User Port connector, for only f20.00. Ready-made interfaces available. For CBM64, BBC- B, and VIC20 at least 8k). CW-only version for SPECTRUM £ 10.
And tour superb program for CBM04, V20, B8C-B, SPECTRUM
LOCATOR QTR or Maidenhead locator or let/long Distance, headings, contest points, converts between locator and lat/long. Tape £6.
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MORSOE TUTOR Britain's best Learn fast in easy stages from absolute beginner to over 40 wpm. Join the hundreds who have succeeded with this program. Tape and full learning guide U. For ZX81.10k oleo.
RAE MATHS All the practice and testing you need. Tape and comprehensive reference sheet detailing all you need to know £8. VIC20 needs expansion ( any). For 7181.10k Moo. Don't let maths make you fail. PASS with this program.
All programs are very easy to use and come with full instructions. Prices include p&p 1st Class by return. Add rl per tape if outside UK or Ireland.
technical software (AR)
FRON, UPPER LLANDWROG, CAERNARFON, GWYNEDD LL54 7RF. Tel. 0286 881886
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MARCH 1985
WOOD & DOUGLAS vvih,
VHF/UHF COMMUNICATION PRODUCTS
A NEW RALLY SEASON BEGINS! During the next months you can meet our happy smiling staff at events up and down the country. Our new illustrated catalogue will be released at the NEC in April along with the new high quality products we have been devising in our winter hibernation!
See you there!
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9.85 9.90
70FM1 70FM3 70FM10
70FM3/10 70FM40
18.45 23.45 41.45
23.95 65.10
70PA/FM10
56.60
70LIN3/LT 70LIN3/10E 70LINIO
27.90 41.05 44.25
70PA2 70PA3 70PA2/S 70PA5
8.10 9.65 24.25 20.10
6FiX2
28.40
KIT
29.75
4580
14.25 17.90 62.25 22.10
5.50 3.30
535
20.10
22.80 3650
5.75 550
12.80 17.80 3345 18.30 52.35
40 15
1890 30.15 32.50
6.50 7.50 15.25 12_80
20.80
144FM2T3 144FM2R5 144SY25(3 SY2T BPF 144 PSI 144
144FM10A 144FM1OB
144LIN1OB 144LIN25B 144LIN25C
144PA3 144PA4 144PA4/S
TE12 PT3 PTK3 PTKIR REG1 SSR1 MPA2 SWR1 CWF1 HPF1
LIFM01 VIDIF WDV400/ 1200 1250DC50
39.35 65.50 78.75 27.90
6.50 7.55
24.15 36.11
38.40 40.25 44.25
8.60 12.86 24.30
6.70 7.50 8.75 12.70 6.95 5.85 6.10 6.35 8.55 5.95
26.95 54.25 63.95
69.95
26.30 4720 60.05 20.65
3.30 5.35
18.50 26.25
28.50 29.95 3285
7.40 8.40 15.30
4.25 4.45 6.05 8.20 4.40 3.70 3.50 5.35 5.80
19 80 38 95
Further details on our product range will gladly be forwarded on receipt of an A5 size SAE. Technical help is available by 'phone (NEW NUMBER) during normal office hours. Kits are usually available by return of post but please allow 28 days for unforeseen delays Please add 75 pence to your total order for postage and handling. Credit card orders are gladly accepted, please give us a Call.
ANYONE CAN SELL A KIT ... REPUTATION SELLS OURS
UNIT 13, YOUNGS INDUSTRIAL ESTATE
ALDERMASTON, READING RG7 4PQ
NSA
Tel: (073 58) 71444 Telex: 848702
RUB BOOKS
RSGB PUBLICATIONS A Guide to Amateur Radio (19th edn) Amateur Radio Awards (2nd edn) Amateur Radio Call Book (1984 edn) HF Antennas for All Locations Microwave Newsletter Technical Collection Morse Code for Radio Amateurs Radio Amateurs' Examination Manual Radio Communication Handbook (paperback) Teleprinter Handbook (2nd edn) Television Interference Manual World at their Fingertips VHF/UHF Manual (4th edn) Meteor Scatter Data
Logbooks Amateur Radio Logbook Mobile Logbook Receiving Station Logbook
£3.91 £3.68 £7.14 £7.35 £6.83 £1.64 £3.84 £11.79 £12.72 £2.31 £7.75 £10.58 £3.51
£2.77 £1.23 £2.87
Mee Great Circle DX Map Locator Map of Europe (wall) World Prefix Map in full colour (wall)
£2.43 £ 1.95
£2.53
OTHER PUBLICATIONS
Active Filter Cookbook (Sams)
£12.71
All About Cubical Quad Antennas (RPT)
£5.83
Amateur Single Sideband (Ham Radio)
£5.46
Revised Amateur Television Handbook (BATC)
£2.95
Antenna Anthology ( ARRL)
£6.00
ARRL Electronics Data Book
£4.47
Beam Antenna Handbook (RP!)
£6.83
Better Short Wave Reception (RPO
£6.83
Care and Feeding of Power Grid Tubes (Varian)
£6.99
CMOS Cookbook (Sams)
£13.07
Complete DX'er (W9KNI)
£7.77
Complete Shortwave Listener's Handbook (Tab)
£12.21
Design of VMOS Circuits with experiments (Sams)
£8.50
FM and Repeaters for the Amateur (ARRL)
£4.30
G-QRP Club Circuit Handbook
£4.52
Guide to Oscar Operating (AMSAT)
£1.78
Hints and Kinks for the Radio Amateur (ARRL)
£4.47
How to Troubleshoot and Repair AR Equipment
£10.47
IC Op- amp Cookbook (Sams)
£11.76
International VHF FM Guide
£2.45
Newcomer's Guide to Simplex and Repeaters on 2M
£1.24
Radio Amateurs Handbook 1985 (hardback)ARRL
£21.90
Radio Amateurs Handbook 1985 (paperback)ARRL
£15.80
Radio Amateurs Handbook 1984 (ARRL)
£6.66
Radio Frequency Interference (ARRL)
£4.18
Satellite Experimenters Handbook (ARRL) £ 10.11
Satellite Tracking Software for the Radio Amateur (AMSAT-UK)
£4.47
Secrets of Ham Radio DXing (Tab)
£7.92
Semiconductor Data Book (Newnes)
£7.97
Shortwave Propagation Handbook (Cowan)
£7.79
Simple Low Cost Wire Antennas (RPI)
£6.83
Solid State Design for the Radio Amateur (ARRL)
£7.87
Television for Amateurs (BATC)
£2.23
UHF- Compendium Parts 1&2
£14.93
Understanding Amateur Radio (ARRL)
£4.73
VHF Propagation Handbook (Nampa)
£3.75
Weekend Projects for the Radio Amateur (ARRL)
£4.95
World Atlas (RACI)
£3.35
OTHER ITEMS Morse Casette stage 1(to 5wpm)
DX Edge (HF propagation prediction aid)
£3.84 £13.98
Membership of the Radio Society of Great Britain le open to ell Radio Amateur and Listeners. For details of sub...lotion and the benefit. of membership, please contact the Membership services Department. All k..,,. in this advertisement include post and pecking. Members of the Society ere entitled to discounts on these prices. Personal callers may obtak. goods minus postage and packing charges.
RSG B Publications
Lambola House, Cranborne Road, Potters Bar, Herts EN6 3JW Telephone: ( 0707) 59015
MARCH 1985
please mention AMATEUR RADIO when replying to any advertisement
35
WIWI AI 1
Come and hear the lkom range on stand A6$-7O at the 111Z6B National Amateur Radio Exhilbition
This year at the NEC. Thanet Electronics will have demonstration facilities only on our main stand, but the range and scope of these will enable you to appreciate fully the superb specifications and quality of all ICOM Amateur Radio Equipment.
You will be able to try out receivers and transceivers as base stations, mobiles and hand-
N-I\ ····` ·
7
New! IC- 31000E
portables in all the popular frequency ranges. Buying ICOM equipment at the NEC. will
not be aproblem as it will be readily available at
any of the authorised ICOM dealers exhibiting at
the show. A new exciting set will be seen at this years
show, it is the ICOM IC- 3200E FM Dual- band
transceiver ( 144-430/440 MHz). This is the
smallest transceiver available.
The IC-3200E employs afunction key for
low- priority operations to simplify the front panel.
LCD display is easy to read in bright places,
showing frequency, VFO A B. memory channel
duplex mode and S' RF meter information. Other features include a10 channel memory able to store operating frequencies. Simplex or Duplex.
A memory lock-out function allows the memory scan to skip programmed channels when not required. The IC-3200E has
abuilt-in duplexer and can operate on one antenna for both VHF and UHF. Options include: IC-PS45 DC. power supply. HS- 15 mobile mic,
SM6 and SM8 desk mics. SP- 10 external speaker and UT-23 speech synthesizer. Agreat future is predicted for the IC-3200E against its rivals, due to the reasonable price of this model. For more details come and
see us on stand A68-70. BCNU.
Km2.90D/190E
290D is the state of the art 2meter mobile, it has 5 memories and VFO's to store your favourite repeaters and apriority channel to check your most important frequency automatically. Programmable offsets are included for odd repeater splits, tuning is 5KHz or 1KHz.
The squelch on SSB silently scans for signals, while 2VFO's with equalising capability mark your signal
frequency with the touch of abutton. Other features include: RIT, 1KHz or 100Hz tuning/CW sidetone. AGC slow or fast in SSB and CW. Noise blanker to suppress.
pulse type noises on SSB/CW. You can scan the whole band between VFO'siscan
memories and VFO's. Adjustable scan rate 144 to 146 MHz, remote tuning with optional IC-HM1 microphone. Digital frequency display, Hi/Low power switch. Optional
Nicad battery system allows retention of memory.
soon to be announcedl
K-7135 New Compact HI. R7000 VIIIMUHIF Receiver.
te'
eeeeee
36
please mention AMATEUR RADIO when replying to any advertisement
MARCH 1985
IE 1`1
K-01E, leatE
The direct entry microprocessor controlled IC-02E is a 2meter handheld features include: scanning, 10 memories. duplex offset storage in memory and odd offsets also stored in memory. Internal Lithium battery backup and repeater tone are included. Keyboard entry is made through the 16 button pad allowing easy access to frequencies, duplex, memories, memory scan and priority.
The IC-02E has an LCD readout indicating frequency, memory channel, signal strength, transmitter output and scanning functions. New HS- 10 Headset, with earphone and boom microphone, which operates with either of the following.. HS 10-SB Switch box with pre- amplifier giving biased toggle on, off and continuous transmit. HS 10- SA Voice operated switch box, with pre-amplifier, mic gain, vox gain and delay. The IC- 2E and 4E continue to be available.
Au/barbed acorn dealers In the UK
Alexian Electronics Ltd Edinburgh. 031-554 2591 Alyntronics. Newcastle. 0632-761002. Amateur Radio Exchange. London ( Ealing). 01-992 5765 Amcomm. London ( S. Harrow). 01-422 9585. Arrow Electronics Ltd.. Chelmsford Essex. 0245-381673 26 Beamrite. Cardiff, 0222-486884. Booth Holding ( Bath) Ltd . Bristol. 02217-2402 Bredhurst Electronics Ltd.. W. Sussex. 0444-400786 Dressler ( UK) Ltd.. London ( S. Harrow). 01-558 0854 D.W Electronics. Widnes Cheshire. 051-42(12559
PHohbobtyotrAocnoiusctsi.csKnLuttds..foBrudckChiensghhiarmes.hi0r5e6.5-o4900480-610625
Radcomm Electronics. Co. Cork. Ireland. 01035321-632725 Radio Shack Ltd.. London NW6. 01-624 7174 Scotcomms. Edinburgh. 031-657 2430 Tyrone Amateur Electronics. Co Tyrone. N Ireland. 0662 2043 Reg Ward & Co. Ltd.. S.W. England. 0297-34918. Waters & Stanton Electronics. Hocklev Essex. 0702 206835
Listed here are authorised dealers who can demonstrate ICON equipment all year round. This list covers most areas of the U.K.. but If you have difficulty finding a dealer near you, contact Minuet IF.lectronics and we will be able to kelp you.
Torso linear Amplifiers
2M -- 100W. £ 79.00. MR -- 150W, £ 139.00. Also available, new G-series with GaAs FET pre-amp. 2M -- 130G. £ 159.00. 2M -- 90G, £ 149.00. 2M -- 40G. £ 89.00. 4M -- 70G, £ 179.00. all inc. VAT.
Carriage charge is free for Cue Dee and Tono special offers.
Cue Dee Antennas Special Offer!
CUE DEE antennas are designed to last for decades -- the best possible aluminium alloy for this purpose is used ( SIS 4212-06).
The booms are made of 28mm tubing with 1.5mm wall, with colour marks clearly indicating where to fit the elements. By using tubular boom, and asynthetic guy wire on the long yagis, the windload is reduced by afactor 0.66 compared to using square shaped material for boom and guying.
The driver element is made of 12mm tubing and features a PTFE (Teflon) insulated gamma match which is pre- tuned at the factory and made for 50 ohm feeder with aPL 259 type connector. No further adjustments or power consuming balun needed. This matching system ensures aclean radiation pattern and transfers the power without losses.
The parasitic elements are made of 6mm solid rod and mounted to the boom with the aid of aCUE DEE element washer, boom to element part and ascrew. This, together with our intelligible asembly manual, makes an extremely easy and solid assembly which assures the long life of aCUE DEE antenna. 2metre Vagis. 4144A -- 4element. 8dBd gain £ 19.00. 10144 -- 10 element, 11.4dBd gain £37.00. 15144 -- 15 element. 14dBd gain £49.00.
Order now while stocks last.
You can get what you want just by picking up the telephone. Our mail-order dept. offers you: free, same-day despatch whenever possible, instant credit, interest- free H.P., telephone Barclaycard and Access facility and a24 hour answering service.
Please note that we now have anew retail branch at 95, Mortimer Street, Heme Bay, Kent. Tel: 369464. Give it avisit, BCNU.
· .eee%
11/4, 011/4'
e 41/ 4.bee e<kerbç:)
-'91ee 19 e
MARCH 1985
please mention AMATEUR RADIO when replying to any advertisement
37
period is to show that there is a great demand for class B Morse.
News and comment from Glen Ross G8MWR
Locators The new system seems to be getting
well established judging by the number of people using them, the only snag at the moment is in visualising just where the other person is. Thinking in terms of 'DL' square has become automatic and easily visualised but ' 0J31' is not that easy. However, all will become clear with
a bit of practice. The response to our offer to calculate
your Maidenhead locator for you has been tremendous, with over 300 letters in the first three weeks of the year. It is
clear that although there have been several articles published on the subject, a lot of people have not fully grasped what is required to calculate the new code accurately.
First, it is not possible to work it out correctly from the existing ' QRA' locator because the large squares that coincide
with the smaller ones actually overlap in latitude but not in longitude. The actual error which is generated by a direct conversion is not large and over normal DX distances it is doubtful if it would be at all significant unless you are chasing
the last kilometre for a distance award. Although Ihave not calculated them it looks as though more significant errors could be introduced by assuming, as most programs seemto do, that the earth is asphere, which of course it is not.
Perhaps we are all getting too concerned with the idea of measuring to the
'nth' degree. You may have noticed that when you used an analogue meter you set the five volt rail to the mark on the meter and left it at that, but when using a digital meter you struggle to get it right to the last . 001 of avolt, and the fact that the circuit will work quite happily plus or minus aquarter of avolt is lost sight of!
We digress, however. If you are sending for your new locator please estimate your latitude and longitude to
within 10 seconds if you want the most accurate result, and please enclose an SAE.
NEC Morse tests Permission has been given for Morse
tests to be taken at the RSGB NEC rally.
There will be acertain amount of time set aside for disabled people, but there will be ample opportunity for everyone to have acrack at it. It is not an ' on the spot' affair, and you will need to book your test in advance in the normal way.
The arrangements are being made by the coast station at Highbridge and you should be able to book through them. This should prove to be apopular facility so please get your application in well ahead of time. Thanks are also due to the test staff for giving up a weekend to come to the show.
Class B Morse Whilst we are on the subject of Morse
remember that class B Morse arrives on 1 April, or it will do if you have sent in your application for a letter of variation. This should be sent to the RSGB, Lambda House, Cranbourne Road, Potters Bar, Herts EN6 3JW. You must enclose two stamps and please mark the envelope 'Class B Morse' to make life alittle easier for them.
It is known that well over a thousand applications have been received and that the letters will be issued from 1 February.
There seems to be little restriction on where you can operate, all your normal bands are available. One thing that is essential is that you must announce your callsign in telephony at the start and finish of every transmission. This effectively means that to send true CW you should use the all mode section of the band, never the CW segment.
You could of course use akeyed audio oscillator picked up on your microphone for practice transmission purposes and you could then use the normal simplex channels. This might well reduce your popularity and it would seem sense to keep all CW sending to the all mode parts of the bands.
Send ' em In! Please send in an application even if
you do not intend to use the facility: the DTI are monitoring the interest and the only way we can be sure to get it continued after the initial one year trial
Repeater news We are now getting regular news
sheets from several of the repeater groups but we would like even more to help keep up to date on happenings in this area.
GB3SF is the first SSB repeater in this
country and is now operational from Sheffield. The big problem in getting into this repeater is the fact that you have to transmit areduced level carrier to it, and this means digging into your rig and doing alittle tweak to allow some carrier leakage. From then on, of course, all your normal contacts will complain about the amount of carrier on your signal.
For more information on this project, plus a discussion of SSB repeaters
generally, see my article in the January 1984 edition of the magazine. At least it is running, and if you want more information on using the machine the man to talk to is Tony G3RKL.
The Aylesbury group have proposals in
the pipeline for 145 and 433MHz units to be installed in the Hemel Hempstead area with the callsigns GB3VB and GB3BV respectively.
The North Yorkshire group were carrying out site tests at the proposed new site for GB3NY, the Scarborough UHF unit.
GB3WI in North Cambridgeshire is in need of funds to extend its activities and donations should be sent to G6XML1 or G4NPH. They also produce a newsletter
which is available for an SAE and asmall donation. GB3GR, the UHF repeater in Grantham, should have now returned to RB11 from its new site.
The new Isle of Man repeater GB3GD (incidentally a callsign ' borrowed' from the Leicester data repeater) should give excellent coverage from its site on the top of Snaefell. To reduce co- channel problems this repeater is having to use a tilted aerial array. It will be interesting to see just how this affects the coverage.
Space The pressure for space is getting so
great that it must now be time to introduce 12.5KHz spacing. This is a feature which has been available on rigs for along time and yet seems to be little used. If you do try it please do not QSY up half achannel from S20 and expect to get no problems.
This idea, if applied to repeaters and with some consideration for geographical spacing, should enable less mutual interference or amuch extended repea-
ter system. Amateur radio is supposed to be a
forward looking hobby and yet we shy away from such a simple thing.
More repeaters The proposed change of site for what
was GB3YJ and is now GB3WK seems to have died the death, for it is still on the old site and giving excellent coverage. The Leicester run must be one of the most comprehensive ranges of repeaters in the country, having either a repeater or a beacon on most bands. At
38
please mention AMATEUR RADIO when replying to any advertisement
MARCH 1985
ON THE BEAM
the moment they are planning a 10GHz input to GB3LE, the 70cm repeater.
GB3NK in North Kent is now back on the air after some service work, and in Cambridge the 70cm repeater has been moved into the town and is giving good results plus a higher level of activity.
Odds and ends
News of another experiment comes to hand. The Austrian authorities have recently issued a licence similar to our own class B. The operators are limited to a frequency range of 144.025 to 144.100MHz for training purposes only; presumably this is a CW extension of their licence. They have also made available a general allocation in the range 2305 to 2320MHz, which is just below the normally used part of this band, but a slight tweak of the local oscillator or a second crystal should enable some nice DX to be worked on 13cm. These allocations are on asecondary basis and are only valid until the end of 1988.
New beacons
Two new beacons are now operational from Greenland, but at present the callsigns are not known. On 50.045MHz it runs 20 watts to a ground plane and the 144.902MHz unit has 10 watts to a Yagi. The 50MHz unit should give agood signal into Great Britain under lift conditions.
The American Radio Relay League has published a document on packet radio detailing the AX25 link protocols. This can be obtained from them or by sending an enquiry to the RSGB.
We have heard of quite a number of things which are knocked out by strong RF fields and the latest to join the group are the Maestro, Cavalier and Sierra cars. Think twice before fitting 100 watt linears in these as you could come to a grinding halt half way through your over as the petrol injection system goes on the blink. The RSGB would like to hear of any problems you may have with these and also with the new ' Ambassador' telephones.
Workshops
You may get this just in time for the next microwave workshop which will be run by the Droitwich club on 25 March, starting at 7.30pm. This follows the very successful event held last autumn. The venue is close to a motorway exit and there will be talk- in on S22. There is a probability of another meeting being held in Sheffield in the spring; more details when we get them or contact Barry G8AGN.
Cobwebs?
The Microwave Society are running
their usual ' Cobweb clobbering' event on 21 April, giving 10GHz operators a
chance to get the gear out of cold storage and make a start to the year's activities.
The RSGB has still not announced the dates for this year's 10GHz cumulative contests, nor for that matter the winners of last year's event; just how long does it
take to sort out approximately thirty entries?
Barking Contest
No, not quite what it seems! This is one of those 144MHz contests run by alocal
club, but which gathers ever wider support. It takes place on 31 March between 1300 and 1700GMT and is run in two sections, one for full legal limit and the low power section where the power limit is 20 watts PEP. You exchange the usual RST plus serial number report, but you also have to exchange the county name. Ideal for county chasing for our new awards.
The scoring is on the basis of one point per contact with the club calls G3XBF and G8XBF counting for 10 points each. Your final score is the number of points
multiplied by the number of counties worked, and entries should be sent to BRS31976, 32 Wellington Road, Rayleigh, Essex SS6 8EZ, to arrive not later than 13 April.
The winner will receive a...no, Ithink we will keep quiet about that, send an entry and find out!
FOR QUALITY COMPONENTS
BY MAIL ORDER
U LT 10VALL
CENTRE ELECTRONICS SPECIALJSTS IN THE SALE AND SERVICING OF VALVE TYPE RAM EQUIPMENT
OFFER EDDYSTONE MODEL 1590 General Coverage Receiver Ex Works Demonstration examples as new condition with one years works guarantee £620.00
OTHER RECEIVERS FOR SALE include the following RACAL RA17 4, f175, RAI7/L @ £195,
RAI17/E @ f2.50. EDDYSTONE MODELS 830/9 4 f155, 730/64 £ 145, 770U @ £115. Also aselection of Vintage Communication Receivers HRO's, AR88's, S27, 3.58X, S504 etc; LISTS OF OTHER RECEIVERS AND ITEMS ETC AVAILABLE
ADMIRALTY B40 Single Side Band Adaptor Units £50 each including connector leads.
Large stocks of assorted vintage components ( 1920's - 60's) to clear Callers only
SPECIAL OFFER TWIN AXIAL COAX CABLE ( 100ohms) uses include Data Transfer, Inter connecting word processors, micro computers etc 12p per metre of £ 10 per 100 metre roll. ( Free sample on request)
ALL PRICES INCLUDE PACKAGING AND DELIVERY
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Radio Amateur Supplies Tel: 0602 280267
Visit your Local Emporium
Large Selection of New/Used Equipment on Show
AGENTS FOR:
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Monday: CLOSED Tuesday - Saturday: 10.00am to 500pm
3Farndon Green, Wollaton Park, Nottingham, Off Ring Road Between A52 ( Derby Road) & A609 ( Ilkeston Road)
MARCH 1985
please mention AMATEUR RADIO when replying to any advertisement
39
THE DREADED
Whilst it may be alliterative exaggera-
tion to state that the Decibel inspires dread, it certainly puzzles some radio
enthusiasts. This may be due to the fact that it is a logarithmic unit, and logs' were traditionally considered to be a subject for the high- flying maths chaps.
This is far from the truth, for logs are simply amethod of easily handling awide
range of numbers. Apart from their use in the Decibel system, logs are used in
other ways in electronics and com-
munications. For example log scales on graphs are very convenient in certain applications, and on the practical side
some potentiometers are designed to exhibit a logarithmic change of resist-
ance. What is alog? Well alog is the power to
which a number must be raised to produce another given number. ' Power' in this sense does not mean electrical or
mechanical power in watts, but is amaths expression signifying multiplying anum-
ber by itself a certain number of times. Squaring or cubing a number is raising that number ' to apower'.
Assuming that ' a', ' N', and ' x', are different numbers, then if a' = N, then x =
log aN. The latter expression is read as ' x
equals log to the base ' a' of N'. The log to
the base ' a' of N is the power to which ' a' must be raised to produce N. Again note that the word power is used in a mathematical sense.
Logs to the base ten are the most usual and are named ' common logarithms'.
However, logs to other bases are sometimes used in communication techniques. Naperian, or hyperbolic logs are such asystem. Sometimes referred to as natural logs they are named after Charles Napier, and are calculated to the rather odd- looking base of 2.71828. This number is given the special symbol ' e',
and is derived from the series:
2.71828 = 1 + 1 +
+L +-
2'
3!
4!
Where the exclamation mark is the mathematical factorial sign. Naperian logs have given rise to aspecial unit, the 'Neper', which is used in network
attenuation calculations. The attenuation in Nepers is given as:
Nepers = log e out
where 1,, is the current entering the
network, and lout is the current leaving
the network. The Neper, being based on exponential logs, is generally used in the
more theoretical calculations. During more mundane day-to-day expressions
of power ratios the Decibel is used. The Decibel uses logs to the base ten,
and is named after Alexander Graham
Bell, the father of the telephone. Ori-
ginally the unit was a ' Bel'. A Bel was
defined as
Pr 10 9m r-2
where P1 is the power to be compared, and P2 is the reference power. The Bel
DECIBEL
J GLANVILLE G3TZG
was a trifle inconvenient as a practical unit so a factor of ten was introduced making the ' Decibel'. A Decibel is one
tenth of a Bel, and is defined as:
10 x log ,0 PI
where PI is tne power to oe compared and P2 is the reference power. This is often read as ' ten log ten P1 over P2 '·
The use of the Decibel is illustrated as
follows: Assume that we have an amplifier into which we insert apower of 10 watts, and the output power is 20 watts. Using the
input power as the reference power P2 this becomes:
Power gain in Decibels = 10 log 10 ..° 0
which is ten multiplied by the log of two. Looking in the log tables for the log of two gives us . 3010. Multiplying this by ten makes 3.010. Neglecting the third digit we round off the figure to 3 Decibels.
Table 1 indicates how a range of increasing power levels in an amplifier could be expressed using an input of 10 watts as the reference power. The table also illustrates that adoubling of power generally taken as 3dB is actually 3.010dB. However, in general use 3dB is quite adequate, for in practice it is often quite difficult to measure fractions of a Decibel.
In the example given above the reference power was 10 watts, but other reference powers may be used in the Decibel system. For example one thousandth of a watt, or 1 milliwatt is often used as the P2 reference power. Decibels used in this form may be written as ' dB ref 1mW', or simply as dBm. Sometimes the m' is printed as a small
letter slightly below the line. This is known as a subscript. Other subscripts may occur in specific applications, notably dB, , which expresses the power gain ( or loss!) of an antenna compared with an isotropic radiator, transmitting equally in all directions. It must be emphasised that the Decibel is an indication of power ratios, and is not an absolute unit such as the volt, or ampere.
Although it is basically aunit of power ratio, the Decibel may be used to express voltage or current ratios, or even airborne noise levels when measuring sound for research or environmental control purposes. For example to express the powers expended in two equal resistors one can measure the
voltages, and the formula then becomes:
dB = 20 log 1°V2 where V2 is the reference voltage.
'Where does the 20 come from?', is a question frequently asked. Well, in comparing quantities such as voltages, or pressures with respect to power levels, the squares of numbers are involved. In logs anumber is squared by multiplying it by 2. This turns the 10 in the power formula into a 20 in the voltage
expression. A similar indication of power can be
made by using the current flowing in two equal resistors. The formula then
becomes: dB = 20 log 1, I1--,2
where 12 is the reference current. For this type of calculation the resistors must be of equal value. Again the figure 20
appears in the formula for the same reason as in the voltage case. Table 2 illustrates a list of voltage ratios based on a reference level of 10 millivolts. It
should be noted that a doubling of voltage is an increase of 6 Decibels, whilst adoubling of power (Table I), is an increase of 3Decibels. The difference is
the result of the squared relationship of voltage with respect to power.
Decibels can be used to give an indiction of air pressure, or to be more exact, an indication of the small air pressure variations that we know as sound or noise. These alternating pressures are specified as Sound Pressure Levels ( root mean square) in Decibels with regard to an internationally agreed ·
reference pressure. The currently accepted reference pressure is 2x 10 -5 Pascals. The Pascal is a pressure unit named after Blaise Pascal who
Table 1
Input watts
10 10 10 10 10 10 10
Output watts
20 30 40 50 60 70 80
Log of ratio
.3010 .4771 .6021 .6990 .7782 .8451 .9031
dB
3.0 4.7 6.0 7.0 7.8 8.6
9 o
V 2
10mV 10mV 10mV 10mV 10mV 10mV 10mV
V ,
20mV 30mV 40mV 50mV 60mV 70mV 80mV
Log of ratio
.3010 .4771 .6021 .6990 .7782 .8451 .9031
20 x log of ratio
6.0dB 9.5dB 12dB 14dB 15.5dB 17dB 18d8
40
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MARCH 1985
THE DREADED DECIBEL
developed a law concerning the pressure of confined fluids.
Small variation This reference air pressure is an
exceptionally small variation, and it represents the lower limit of hearing for ahealthy person. To gauge some idea of this minute pressure, consider the ' bar' which is about average steady state atmospheric pressure. Meteorologists measure slow changes in millibars, with 1013.25 millibars often taken as a standard atmosphere for aerodynamic purposes. However a variation of 2 x 10 Pascals is a pressure variation of . 0002 microbars, which is much less than one millionth of atmospheric pressure. The human ear is asensitive transducer!
The formula for Sound Pressure Level becomes:-
SPL dB = 20 log 1,0 T:72
where P2 is the reference pressure variation of 2 x 10 5 Pascals or . 0002 microbars.
The 20 factor is analogous to that in the voltage formula, for voltage is aform of electrical pressure. A doubling of sound pressure level results in an increase of 6 Decibels.
The formula for sound power levels is:
Sound power in dB = 10 log IP, owe1 r Power 2
where Power 2is the reference power of
10 12 watts per square centimetre. Again this is a very small number, illustrating the sensitivity of the ear, and the desirability of using logs to deal with a wide range of numbers. Using the sound power formula, a doubling of power results in an increase of 3 Decibels.
Sensitivity Decibels may be used to state mic-
rophone sensitivity. This is usually quoted in volts for a given sound pressure level in SPL dB. The specification for communication microphones is usually in Decibels below the output of a ficticious microphone assumed to have an output of 1 volt for an SPL of 1 microbar.
On these terms a carbon microphone would have asensitivity of about - 39dB. A tie clip microphone operating on the electret principle would have asensitivity of about -60dB ref 1 volt per microbar.
Microphones of a precision nature used for research or environmental control purposes usually adopt a different SPL reference pressure of 1Pascal. (The Pascal is 10 microbars, or 1Newton per square metre). One Pascal represents 94dB SPL so a typical precision microphone would be quoted as - 38dB reference one volt per Pascal SPL. This latter microphone would produce an
open circuit voltage of about 12.5 millivolts when subjected to an SPL of 94dB. This level of 94dB represents a fairly loud noise, for 90dB SPL is generally considered to be the limit of safety for a person exposed to such a noise for normal daily working hours.
Some of the above may appear to be a trifle theoretical to the average radio enthusiast, but there are other uses of the Decibel which relate to the practical day-to-day working of an amateur radio station. In the past, British regulations stipulated the power limits of an amateur transmitter in terms of the direct current applied to the final stage. In future, power limits will be specified in dBW, that is Decibels relative to 1Watt. Being able to handle Decibels is therefore of considerable practical use.
Log it? Readers who wish to increase their
skill at using Decibels should obtain aset of common log tables, and work out some Decibel lists for themselves. Log tables appear in the back of many text books, or they may be obtained in the form of reasonably cheap four figure log booklets. These booklets often include instructions on their use, or ' how to enter the tables', as it is said. A little time spent with the log tables will improve confidence, and make the dread of the Decibel athing of the past.
'-'Cs
RM-1 RADIO MODEM
Specification
The RM-1 is a ruggedly built, steel cased unit, capable
of use on all standard amateur data communication
modes:
RTTY:
170Hz shift transceiver ( 425, 850Hz receive)
(IARU tones frequencies) -- data rate up to
100 Bauds.
ASCII: 800Hz shift transceive ( IARU tones) -- data
rate up to 1200 Bauds.
CW:
Transceive.
AMTOR: 170Hz shift transceivé -- data rate at 100
Bauds.
Computer interfaces at both TTL and RS232 levels are
provided and the front panel lock indicator doubles as a
tuning indicator.
Power input is 12V D.C. at 150mA.
The RM-1 is intended for use with suitable software in
your computer -- much of which is available from ICS.
Made in U.K.
Access 411`
Price: £ 89.50 inc VAT £1.50 P & P
Compatible Software
RM-1/CBM-64 RTTY/ASCII/CW software,
cable
£39.00
RM-1/VI C-20
RTTY/ASCI I/CW software,
cable
£39.00
RM-1/BBC-B
RTTY/CW software,
cable only
£39.00
MBA- TOR
Amtor/RTTY/CW/ASCI Isoftware,
cable
£69.00
Please add P & P: £ 1.00 each
ICS ELECTRONICS LTD
PO BOX 2, ARUNDEL, WEST SUSSEX BN 18 ONX
VISA
Phone: ( 024 365) 590
MARCH 1985
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41
THE MULTI P6 2m / 70cm
MOBILE AERIAL
Reviewed by Bill Sparks G8FBX
When reading reviews of commercial equipment one feature is commonly experienced: the reviewer invariably subjects the equipment to searching laboratory tests and then finalises his review with a short paragraph on the practical use of the equipment. Since the majority of potential users are interested in the uses to which they personally can put the equipment, or the benefits they can receive in practical day to day use, the technical guff is not of primary interest to them. What they want to know is, ' Does it work?', and if so, ' How good is
it?'. In view of this, the approach taken in
reviewing the P6 was to evaluate its performance in practice and later to take some comparative measurements to establish astandard of performance.
Design considerations Aerials designed for mobile use at VHF
are essentially acompromise, since any one aerial will only give its best performance when set up in relation to its immediate surrounding, hardly possible in a widely varying situation. The condition affected to the greatest degree in mobile use is the relationship to earth, so that an aerial in which this
condition is given prime consideration must by virtue of its design offer some
advantage. The P6 is basically a shorted quarter-
wave section of line, the line impedance being in the order of 350/450 ohms. The
significance of this will become obvious later. This means that the open end of the line can be adapted to feed avariety of aerial loads.
The section itself performs adequately as a quarter- wave, and radiation in accordance with the normal quarterwave pattern is as expected. The major
advantage is that the stub section, being correctly matched, does appear to be
slightly ' gainier' than a normal quarterwave in the same position. Since the stub
consists of two parallel stainless steel rods some of 3/8 a wavelength long secured into amounting block, the use of a sliding solid stainless steel block,
which can be adjusted along the stub, enables atrue quarter-wave point to be
established. Coaxial cable fed to a further sliding
block, this time of high quality insulation, enables the matching point to be clearly established. Once these two points are
finalised the aerial is ready for use. The stub area is shown in the diagram.
Element head fixing
Note holes in knurled faces. Allen Key can be used as Tommy Bar
- Slot for element
Stub section details
Head can be foxed in any horizontal plane line
Seal Cap
Colinas, element ( horizontal)
1
Top block
o
Boss to ht at A
Height adjustment of colinear element
Normal hole position of stub element
Solid base mounting block
Blor.k base mounting
SCIeW
--Stub shorting block (stainless)
Position shown to indicate ease of rotation of DF loop of colinear
During the tests, in comparison with the quarter- wave the height of the main lobe in relation to the car roof was considered to be relevant to the
improved performance of the P6 over the equivalent quarter- wave on a mag
mount. The true earth point of the P6 is
actually the shorting block and not the
base fixing. Hence the unit worked effectively irrespective of the ground plane, an obvious advantage to caravan
owners and mobile use in fibreglass roofed vehicles.
A boss is mounted on one of the stub elements, with a knurled screw driving
into aslot cut into the boss. This allows various attachments to be fitted, one of which is a half- wave length of stainless
steel rod. The method of attachment permits the
length of the element to be adjusted. In this configuration the aerial becomes aJ aerial and the current loop is effectively pushed up the half- wave section, thereby giving true radiation in the horizontal field with very little vertical,
the ideal requirement for vertically polarised FM signals. Measured against a 5/8 whip one feature was immediately apparent: the susceptibility to flutter was less pronounced. There was a marginal.
gain increase over a 5/8 whip and the performance was slightly down on a 7/8
whip. The aerial as such is avery close relation to the Slim Jim.
By removing the half- wave rod and replacing it with astainless steel ring the
aerial then becomes: a) avariation of the Halo with the ring in the horizontal position; b) aDF loop with respectable sensitiv-
ity with the ring in the vertical
position. With (a), and operating sideband in contact with fixed stations, an immediate
improvement was noticed. The ' around
42
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MARCH 1985
MULTI P6 REVIEW
town' operation was immeasurably improved, giving no reflection effects as received with vertical aerials, and because of the polarisation gain giving a
marked increase in signal level. One significant feature of this ' Halo' was the absence of the usual null in the radiation pattern. Only a slight variation was
measured. With ( b), the advantage of being able to
achieve a certain discrimination between signals off the side when operating from a static position was apparent. Although only simple forms of
DF operation were attempted the possibility of using the techniques on VHF DF hunts was considered viable.
Collinear The end of the second stub element is
protected by a plastic sheath. Upon removal of this sheath a third element may be fitted, and by changing the angle of the original half- wave vertical into the horizontal plane a ' double zepp' type of
aerial is created, ie a 2 half- wave collinear.
The 350 ohm feed is now significant, since maximum gain is achieved with two half- wave aerials fed in phase and closespaced when fed with 350/400 ohm. The effect is to give some 2dB gain over a dipole when the two half- waves are in the same plane. By varying the included angle afurther slight increase of gain is obtainable in a favoured ( included angle) direction, but not of any great value: again, more later ( see diagram).
By leaving the new section in position and returning the half- wave section to vertical some rather interesting effects occurred. Looking at the 145MHz downlink on Oscar 10, a certain degree of
directivity was observed with a vertical angle at amaximum of around 35°. This is mentioned in passing and is not asales point as claimed, but is well worth further
investigation since the next point of discussion is the fact that all the above are repeatable on 70cm.
Re-adjustment The only variation to be considered
before discussing the 70cm performance is that when using the aerial as a collinear it is necessary to re- adjust the feed- point of the co- ax. The purist would probably use a balun at this point to equalise the currents in the two stubs more effectively, but it will be noticed that one stub leg is slightly longer than
the other. Measurement of stub current with an RF sniffer indicated areasonable
balance, and one wonders whether this leg length variation is of significance.
70cm The performance on 70cm was initially
viewed with a certain scepticism, since compromise indicates to the writer a failure to achieve. However, after carrying out many tests on both SSB and FM, vertical and horizontal, the results were very encouraging. The use of the collinear from a good spot was an eyeopener, and after further investigation some 5or 6dB of gain was measured. The fact that 2x3half- waves were now being fed in phase led to a rapid session with classic radiation patterns and apencil to
try to understand why. It appears that successive cancella-
tions and additions in the forward pattern result in a quite sharp forward beam with avery low angle of radiation. The other characteristics of the aerial were equally impressive.
The equipment is made from stainless steel metalwork throughout, and is manufactured to a degree of quality rarely seen in amateur aerial construction.
The use of Allen screws to fix some of the components may give rise to problems in mobile use due to vibration, although none was experienced during the tests. The Halo ring itself may be improved mechanically, since a certain degree of floppiness was noticed. This did not have any effect on the performance and may appear trivial, but we must remember that the reviewer of the Rolls Royce did complain about the noise of the clock ticking, and when one is evaluating aRolls Royce of aerials such criticism is valid.
To the writer's mind the aerial is a valuable piece of equipment both to the serious experimenter and the mobile user. Although initially intended for mobile application its versatility makes it an ideal base unit for further experimentation. The writer's version is definitely not being returned after review, since many hours of fun are
envisaged with it!
Further experiment Some consideration may be given to
extending the collinear sections from half- waves to 0.65 waves. This will in effect give afurther 1.5dB gain, and the
aerial then becomes bi-directional with approximately 3.5dB gain over adipole: a rather useful device when out mobile on a picnic or operating from acaravan, or when an opening suddenly appears when you are far from home. Purchasers
of the equipment will think up all sorts of applications since it is virtually an aerial experimenter's Lego set, besides having avery effective practical day to day use as originally supplied.
Briefly, the aerial can be used as a simple mobile, from a static site, as a collinear beam capable of rotation, possibly ( requires further check) Oscar 10 from static positions or even mobile, DF hunts, SSB mobile, and V beam when static, all of these being optimised, ie the aerial is really effective on all the above
situations. After many years of work on amateur
aerials the writer's only complaint is that he did not think of it first. The versatility is quite impressive, and its small dimensions when dismantled makes it an ideal aerial for hotel use, picnics and caravan holidays besides its mobile applications.
MARCH 1985
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43
THE 11m CB TO
10m AMATEUR BAND
PART FOUR
Alook at the dedicated PLL chips used in American CB
rigs which prevent modification for use on other frequencies
CONVERSION GUIDE
ROGER ALBAN GW3SPA BSc. C ENG, MIEE
On Wednesday 4th August 1976 the Federal Communications Commission (FCC) reviewed the operating rules for
Citizen Band radio in the USA, increasing the number of channels from 23 to 40. This change was prompted by the large number of imported sets that were illegal because they were capable of operating on more than 40 channels, since they contained a PLL chip that meant the rig could easily be converted to cover additional channels ( such as the MC145106 or PLL02). The FCC were keen to pressurise the manufacturers of CB rigs to design their sets to contain dedicated PLL chips that were not easily converted to cover additional channels.
The CB manufacturers under pressure
began to use some very sophisticated ways to prevent equipment from being modified to operate on any frequency other than the American CB channels. Their main method was to use aPLL chip which, first of all, only requires asingle crystal, and secondly, is internally programmed to reject any non- legal channel codes on its program pins. What happens is that the PLL chip has a permanent memory inside it which can only recognise programming logic codes that are part of this memory.
Sanyo LC7120 One of the first chips to enter the
American market was the Sanyo LC7120 or equivalent MPD 2810C (Figure 1). This chip contains acode converter or Read Only Memory ( ROM) which stores the required program code required for transmit and receive on each channel. The advantage of doing this is to overcome the problem of the previous examples where complicated mixing methods were used to obtain the correct frequencies for the receiver 1st mixer and transmit frequency. The transmit/ receive divide- by- N' number is selected by having the logic level on pin 8logic 1' for receive and logic ' 0' for transmit.
To alter the program code from one
channel to another the code converter is fed with aunique code on pins Pothrough to P5 . This code is shown in the truth table (Figure 2). You will note that Poto P3 represent the least significant digit of the channel number, and P4 and P5
represent the most significant digit of the channel number with the exception of Channel 40 ( being represented by the code 00). If one tries to select an unlisted code such as 315 with all the program inputs at logic level ' 1' the chip will not
accept the code and will in turn select Channel 40 and set the lock monitor to inhibit the transmitter. Thus it is difficult
to use this particular chip for other
applications because of the strange frequency jumps in American CB.
However, the technology of this chip is that Fin' must be kept under 4.5MHz, therefore down- mixing must be incorporated between the VCO and Fin'. It is
therefore possible to use this chip on 10m FM, with the disadvantage of some channels not having sequential 10KHz increments.
The LC7120 chip is used in the Colt 444 and Super Star 95 American rigs (Figure 3
shows the block diagram). On transmit the frequency of the VCO is added in a
mixer to the reference oscillator of 10.24MHz to arrive at the transmit frequency. On receive the frequency of the VCO is fed direct into the receiver 1st mixer and is subtracted from the wanted
incoming signal to arrive at the 1st IF frequency of 10.695MHz. With the
Flg 2 LC7120 truth table
Fume«
2"
Chaml
01 02 03 04 05 06 07 08 09 10
Ps P4 Pa Pa Pi Po
2
1
8
4
2
1
0
0
0
1
0
0
1
0
0
0
1
1
0
1 0 0
0
1
0
1
0
1
1
0
0
1 1 1
0
1
0
0
0
0
1
0
0
1
1
0
0
0
0
14
1
0
1 0
0
25
0
0
1
0
1
36
1 0
1
1
0
39
1
1
0
0
1
40
0
0
0
0
0
1oooooooooo . . o . . .- . . ..- . . .- o
44
please mention AMATEUR RADIO when replying to any advertisement
MARCH 1985
CONVERSIONS
flexibility over ' divide- by- N' number between transmit and receive, only one mixer crystal oscillator is required.
If the rig is to be used on 10m FM, the mixer crystal oscillator will require to be exchanged for a 17.655MHz crystal if Channel 30 is to correspond to the calling frequency of 29.6MHz. On Channel 30, the VCO will be operating at 19.36MHz on transmit and 18.905MHz on receive. Following down- mixing with the 17.655MHz crystal oscillator 'Fin' will be 1.705MHz on transmit and 1.25MHz on receive, corresponding to a ' divide- by- N' number of 341 for transmit and 250 for receive. Please note that the ' divide- byR' ratio is 2048 and the reference frequency at the phase detector is 5KHz.
When converting these American CB sets to 10m FM, it has also been found necessary to alter the capacitance of some of the tuned circuits. In general terms the rule of thumb seems to indicate that the tuned capacitance should be exchanged for the next lowest preferred value.
To identify acircuit configuration, first of all examine the type of phase locked loop chip being used, and the frequencies of the crystal mixer oscillator. This will certainly assist in identifying the circuit.
Sanyo LC7130 Towards the end of the 1970s an
improved PLL chip emerged from the Sanyo stables with an improved maximum 'Fin' of 20MHz. This chip was known as the LC7130 and featured in the majority of American CB sets manufactured in the early 80s. The main advantage of having achip capable of handling a high frequency 'Fin' is that you can
dispense with the down- mixing equipment and thus make the set difficult to modify for use on other frequencies.
Figure 4 shows the pin out arrangements and the block construction of the chip. The code converter here is called a Read- Only- Meaning (ROM). The ' miss code' ( MC) pin has been separated from the ' lock monitor' ( LM) on this chip. Other features include the ability to select Channel 19 and Channel 9 by putting logic level ' 1' on either pin 8or pin 9. If you happen to put logic level ' 1' on both pin 8and pin 9then the miss code output pin will be at logic level ' 1' indicating acoding error. Unfortunately you cannot cheat with the chip by trying to select an undefined input code. The permitted codes and ' divide- by- N' ratios are given in Figure 5.
No down- mixing The ' divide- by- N' numbers were
devised by the manufacturer to be used in the circuit configuration shown in Figure 6. One will note that for the first time due to the high frequency capability of 'Fin' there is no down- mixing used within the phase locked loop circuit. The transmit frequency is derived by mixing the VCO with the crystal oscillator reference frequency of 10.24MHz. On the receiver side the VCO is fed directly to
02 2133 3 DP 4 DS 5 04 Teat 7-· C11194-4 C149 'PAC 10-
\-1
mI2 X,
X m0
4,, 0
'47110 Tam 04 1/04,0
osso
11·1·44mxe
\
Progr·rneMe
1101911
Un1Polt upmIdetecton bexpansmn mrcuo
mum. 4944.,4u. · cheeve pump
Fig 3 Block diagram of Colt 444/Super Star 95
19 34111114
47310P
VCO
141.··
10 241.1114
1114/11·4
6 P
6559104 70614114s s.l 2614144
V 29 414114 111 · 44 11. 4.-414 141.··r
Fig 4 LC7130 PLL chip
10 · 561111Ma
10 2414111·
1411
459,14114
Fig 5 LC7130 program data and + Al ratio
CHANNEL
NUMBER
P,
P,
P3
P2
P1
1
0
0
0
0
0
2
0
0
0
0
1
3
0
0
0
0
1
4
0
0
0
1
0
5
0
0
0
1
0
6
0
0
0
1
1
7
0
0
0
1
1
8
0
0
1
0
0
9
0
0
1
0
0
10
0
1
0
0
0
11
0
1
0
0
0
12
0
1
0
0
1
13
0
I
0
0
1
14
0
1
0
1
0
15
0
1
0
1
0
16
0
1
0
1
1
17
0
0
0 1
1
18
0
1
1
0
19
0
1
1
0
0
20
1
0
0
0
0
21
1
0
0
0
0
22
1
0
0
0
1
23
1
0
0
0
1
24
1
0
0
1
0
25
1
0
0
1
0
26
1
0
0
1
1
27
1
0
0
1
1
28
1
0
1
0
0
2a9o
1 1
0 I
o 1
0 o
0
o
31
1
1
0
0
0
32
1
1
0
0
1
3343
1 1
1 1
o 0
0 1
o 1
35
1
1
0
1
0
36
1
1
0
1
1
37
1
1
0
1
1
38
1
1
1
0
0
3490
o 1
o 1
o 1
0 o
0 o
29 6141114 10 241414
Ro
Po
N
1
3254
0
3256
1
3258
0
3262
1
3264
0
3266
1
3268
0
3272
1
3274
0
3276
1
3278
0
3282
1
3284
0
3286
1
3288
0
3292
1
3294
0
3296
1
3298
0
3302
1
3304
0
3306
1
3312
0
3308
1
3310
0
3314
1
3316
0
3318
o 1
3320 3322
1
3324
0
3326
1
3328
0
3330
1
3332
0
3334
1
3336
0
3338
1
3340
0
3342
MARCH 1985
please mention AMATEUR RADIO when replying to any advertisement
To N
3345 3347 3349 3353 3355 3357 3359 3363 1185 3367 3369 3373 3375 3377 33793383 3385 3387 3389 3393 3395 3397 3403 3399 3401 3405 3407 3409 3411 3413 3415 3417 3419 3421 3423 3425 3427 3429 3431 3433
45
CONVERSIONS
the receiver 1st mixer -- Figure 6shows the circuit operating on Channel 30 American AM at a frequency of 27.305M Hz.
The designs of the LC7130 certainly made it very difficult for American CBers to modify this circuit to give them
additional channels, but it is relatively easy to modify for use on 10m FM.
-L 10 24M11.-T-
LC7130
Y. 17 065MHz Pe 16 61MHz
P
VC 0
10·24MHz
V 27 305MHz Chan 30 PM
10 24MHz
27.305MHz
LC7130 conversion to 10m One must introduce amixer and crystal
oscillator into the phase locked loop to ensure that the frequency appearing at 'Fin' remains the same as for the American CB band. Figure 7shows the transceiver operating on Channel 30 with the phase locked loop mixer in circuit. From the previous example Fin' on transmit should be 17.065MHz. With a transmit frequency of 29.6MHz the VCO needs to operate at 19.36MHz, giving a difference between the VCO frequency at 'Fin 'of 2.295MHz. Again on receive the difference between the VCO frequency and Fin' remains at 2.295MHz. This is a simple way of converting this American
CB design to operate on 10m. It is worth noting that some of the
channels will not increment the frequency in 10KHz steps due to the American designation of channel and frequency allocation previously discussed. However, this modification should prove to be successful and reasonably cheap to perform. For those of you contemplating this modification, a typical circuit diagram of an American CB set
41551rH
2nd
1 le
ra111--IRF
Rg 6 Block diagram of transceiver using LC7130 PLL chip
10 24191ez y
T. 11-011SZAH· Pr le elk.H.
Tr 19 36 MHz 11 9059111r
V C0
V 29 ,60.911. Ch... 30 lOrn
10 241.1Hz
10 24erelie
he·1 pee
2 265MMe
4156.·
2,4 erne*
1H If 10 695
p
Fig 7 Block diagram of converted transceiver using LC7130 PLL chip
29 1301.1,
using the LC7130 is shown in Figure 8.
The circuit of this American set was designed for amplitude modulation and details of providing FM will be given later in this series.
Next month In the next part of this series we look at
UK CB specification and the conversion of rigs using the LC7137 PLL chip to the 10m amateur band.
0.
este...e.·
'Pm P·Pio..runoe.nt«.·
46
please mention AMATEUR RADIO when replying to any advertisement
MARCH 1985
BACK TO BASICS
Last month we dealt with the ins and outs of the receiver, so in this issue we tackle transmitters. The subject of transmitters is avery important one. It is easy to see that a transmitter, in the hands of an unknowledgeable operator, could well cause widespread interference, not only to other users of the amateur bands but also to services outside of those frequencies on which the transmitter is operating.
Out of band The majority of the amateur bands are
shared with other services but by far the most common cases of interference from transmitting equipment arise out of it not being set up or tuned correctly, allowing it to give off spurious signals that find their way into other equipment situated locally. Examples of such equipment include a neighbour's television receiver, radio or even hi-fi amplifier.
Even a well set up transmitter can cause interference to nearby receivers in amultitude of ways, some of which will be discussed as we progress and others of which will be looked at later on in the series.
You can soon see why certain aspects of transmitter design are very important; take the oscillator for instance. Just as the oscillator in areceiver must be stable enough to stop the receiver drifting off the wanted frequency, so the design of the oscillator used in atransmitter must be such that it does not allow the transmitter to move away from the frequency that it is tuned to. Not only would this be inconvenient for those receiving the transmission but it could cause the transmitter to drift onto someone else's frequency, or even out of the allocated frequency band altogether.
As well as the oscillator stage, you are also expected to understand the basics related to the other transmitter stages, such as frequency changers or multipliers and power amplifiers. Having seen from last month's chapter on receivers that there are various modes of emission in current use we shall, in afew moments, also look at the methods for generating those different modulation modes. Before that though a brief word about transmitters in general.
Transmitters The role of the transmitter is to
generate radio frequency power. The RF signal produced may be keyed or modulated in anumber of ways, so that it can convey information to a receiving station. Up until fairly recently, amateur transmitters were relatively easy to design and build compared with communication receivers, their circuitry being based on valves and the number of stages they used being few in number. That was in the days when the more common modes of transmission were amplitude modulation (AM) or CW, but
Bill Mantovani G4ZVB continues his common-sense approach to passing the RAE. This month:
TRANSMITTERS
Antenna
Crystal Oscillator
Key
Fig 1Block diagram of asimple telegraphy transmitter
Power supply
with the rapid increase in popularity over recent years of single-sideband opera-
tion, all that has now changed and today's amateur transmitter design is somewhat more sophisticated than its predecessor.
The significant changes that transmitters underwent during the late ' 60s and '70s also brought about the now common practice of incorporating the transmitter and the receiver in the same design, hence the transceiver.
All of this does not mean that the traditional transmitter designs are no longer suitable and in fact many amateurs who build their own equipment still do so along the old lines. OW transmitters in particular need not be all
singing, all- dancing in order to achieve good results and this should not be forgotten by the newcomer who
suddenly finds himself confronted by today's crop of ' do everything' black boxes.
From Figure 1you can see that asimple transmitter need consist only of akeyed oscillator connected to an antenna, an entirely suitable and extremely cheap way of getting on the air on OW on a particular band or spot frequency. To operate on different bands or in other
modes we need to add afew more stages but before continuing, let us look at the oscillator stage in more detail.
Table 1lists the UK HF amateur bands together with the three new bands that become available as aresult of the 1979 World Administrative Radio Conference.
The WARC bands, as they have become known, are too new to have had any
influence on transmitter design over the
years, so we shall leave them for a moment and examine first the previously available HF bands. A quick study of the bands reveals that they are harmonically related and this is shown in the right hand column of Table 1. This, and the fact that these bands also had a harmonic relationship to certain TV channels, led to the emergence of afairly standardised approach to the design of transmitters so as to keep any possible interference to television ( TVI) to aminimum.
It is obvious from Table 1 that an oscillator having a maximum frequency range of 1750 -- 2000KHz could be used to cover all of these amateur bands if the output frequency from the oscillator were multiplied by the appropriate
factor. For example, to work on the 160m band ( or Top Band, as it is known) no
multiplication is necessary but to work
on the 20m band afrequency multiplication of 8times is required. An alternative
Table 1
Harmonic relationship of the HF bands
Band ( MHz)
Multiplication factor
1.8-2
3.5-3.8 7.0-7.1
14.0-14.35 21.0-21.45 28.0-29.7
x 1 x 2 x 4
x 8 x12 x16
MARCH 1985
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47
BACK TO BASICS
approach to the above for the generation of the frequencies would be to use a
mixer and two oscillators, but this would be much more complex.
The mixer is used to mix the outputs of
avariable frequency oscillator (VFO) and a fixed frequency, crystal controlled
oscillator. This arrangement can be
made to produce a frequency output in any band required by switching in crystals of the appropriate frequency, whilst the VFO is used to tune across the band as normal. It is this type of circuit that can be used to cover the new, nonharmonically related WARC bands and
as it is also an arrangement found in SSB transmitters, it will be looked at later.
313 MHz
1 allilMa
o MHz.
41i1Ma.
2114114a
VFO
1 I -2 MHz
a .....
·ioP
3
2
2
2
Fig 2 Block diagram of atypical transmitter arrangement
to PA 211111Ha
WI
A note here about TVI. The TV frequencies most susceptible to interference from amateur transmitters were in, the VHF band 1 range but these fortunately ceased to be used for
television broadcasting at the beginning of January this year. This does not
however mean that interference to these frequencies is no longer a problem for the amateur because the band will eventually be assigned to other services, which could be just as susceptible as the old 405- line TVs were to this sort of interference. You can therefore be sure that the design philosophy that has existed up until now will continue to be adopted for some time yet, particularly by those constructing home-brew equipment.
Taking the simple transmitter block diagram of Figure 1 a little further
produces the typical transmitter arrangement shown in Figure 2. It consists of a VFO followed by a fre-
quency multiplier (collectively known as the exciter), the output of which is fed into apower amplifier stage and then to the antenna.
Where a number of frequency multiplication stages are used, for output on avariety of bands, the output from each multiplier stage must be switched to the
input of the power amplifier in turn, as shown in Figure 3.
The variable frequency oscillator allows the transmitter to be tuned to the desired frequency, and the term netting refers to the tuning up onto afrequency that is already in use by another operator, in order to reply to his call or to join in with a conversation. The more commonly used circuits for aVFO are the Colpitts or the Clapp-Gouriet type
oscillators, but any of the other oscillator circuits may be used.
Frequency stability As already mentioned, an important
factor in the design of the VFO is its frequency stability. This will prevent the transmitter from possibly drifting outside of the permitted band or outside of the bandpass of a receiver ( see last month's Part 4 on receiver bandpass).
SSB transmitters in particular should have good stability and because the resonant frequency of atuned circuit is
Fig 3 Block diagram of an exciter designed to cover all bands from a VFO tuning 18-2MHz
Anion..
Pow.,
Fraquancy
VFO
Modulat.
St·bIllx·d noOPIY
Fig 4 A typical frequency multiplier circuit
governed by the value of any inductor and capacitor making up that circuit, the
construction of the VFO should be such that things like mechanical shock in no way cause the values of Lor Oto change.
Coils should be tightly wound on grooved formers and the variable capaci-
tor must be of good mechanical construction. The wiring between inductor and capacitor should be kept as short as possible and rigid enough to prevent mechanical vibration. Another factor that could affect the stability of the VFO is changes in ambient temperature.
The effects of temperature on a VFO may be kept at aminimum by situating it
as far as possible from any heat source and by using an air- cored coil as and where necessary. In atransistor oscillator, the circuit should be designed such that the effects of changes in transistor capacitances are kept to aminimum. This is readily explained in Chapter 5 of the
RAE Manual but make anote of the use of a capacitor having a negative tempera-
ture coefficient to compensate for any changes in value to temperature of the capacitors making up the tuned circuit. Remember then, use only good quality components for the tuned circuit of a VFO and make sure it is soundly made.
External factors
There are also external factors that have an influence on the VFO, such as how much loading the following stage exerts or whether the power supply
voltage fluctuates. Loading on the VFO
should be light as heavy loading could stop it oscillating altogether or could cause the generation of excess heat if it has to deliver too great an output voltage. Consider the VFO as aconstant
frequency small signal source and ideally isolate it from following stages by aClass A buffer amplifier. As for keeping
the power supply at aconstant level, this can be done by using a simple Zener diode to stabilize the supply voltage.
It is not usually advisable to key the
VFO as this too can affect frequency stability. Going back to Figure 3, with the VFO running at the lowest frequency which is fed into frequency multipliers, any possible frequency drift would also be effectively multiplied in these proceeding stages, so you can see why this is such an important subject. Remember
too that when a transmitter is first switched on from cold some frequency drift is almost inevitable during the first few minutes. This is why it is always advisable to switch the transmitter on
48
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MARCH 1985
BACK TO BASICS
some 15 minutes before it will actually be used, to allow the VFO to settle at its operating temperature.
Frequency muMpliers A frequency multiplier is normally a
low power device operating in Class C mode to produce an output which is rich in harmonics. A typical circuit of a transistor frequency multiplier is shown in Figure 4. The tuned circuit connected to the collector is set to resonate at nxf, where n is the multiplication factor required ( ie, times 2or times 3) and fis the frequency of the input voltage. A higher multiplication factor than 2 or 3 may be used but the output then becomes progressively lower.
The tuned circuit itself may consist of a small, possibly slug- tuned coil and a variable or fixed capacitor, but at higher frequency ranges the capacitor can often be omitted and the coil persuaded to resonate using only stray circuit capacitance of afew pF. The output from the frequency multiplier is connected to the following stage via a capacitor, the value of which will vary according to frequency.
For VHF ( 70MHz and 144MHz) and UHF (432MHz) bands, exciter design normally follows that used for HF equipment but, because of increased circuit losses at these higher frequencies, it is often necessary to incorporate abuffer amplifier before the output stage. Because of stability problems, crystal oscillators were most often used but the mixer- type VFO and phase- locked loop techniques are now becoming much more common. From the block diagram in Figure 5of a 144MHz transmitter you can see that the addition of an extra tripler stage would give an output on 432MHz, and that by using a slightly different crystal frequency in the oscillator and the first two multiplying stages an output on 70M Hz is achieved.
Power amplifiers Now let's look at the power amplifier
(PA). Valve PA design differs considerably from transistor RF power amplifiers, mainly because the transistor has amuch lower input and- output impedance compared to the valve and because these impedances decrease as the power level increases. Transistors are also very vulnerable to excessive heat and will stand nowhere near as much misuse as avalve.
This means that with high power transistor PAs, close attention must be paid to mechanical construction with regard to heatsinking. The rating factor for the devices used should be very conservative and, when in use, care must be taken to ensure that the antenna is correctly matched to the PA output stage to avoid any possible damage. Commercial transistor RF power amplifiers and transmitters usually incorporate some protection circuitry to reduce drive if the antenna presents aserious mis -match to the output, another reason why antenna matching to atransistor PA is important.
Buf . for
2
3
1 · ,T.P
144MHz
1441.114:
72Mlis
/Crystal
3
Osc
/.4
1 6-- Bkleit
Flg 5 Block diagram of a VHF transmitter
At VHF, low power outputs of, say, 25 watts or less are quite common and can easily be achieved with the use of relatively cheap transistors. This is a popular solution for portable or mobile working and aseparate higher power PA stage can be added as and when required. Atypical circuit for alow power 144MHz transistor PA is given in the RAE Manual, together with a brief description. This shows the generally preferred L- pi output circuit arrangement, which should be noted. For medium and high power levels at VHF and UHF though, the transistor normally has to make way for valves in the power output stage.
HF power amplifiers are usually required to operate over several bands at higher powers than the above. Because of a transistor's low output impedance, somewhere in the order of 1-10 ohms for a typical 100W PA, the conventional pi- network output arrangement becomes impractical due to the values of Land C that would be required.
The increasing availability of highpower field-effect transistors helps designers get over this problem but a more common solution is to use broadband transformers on the input and output of the transistor. The input impedance is first transformed down to below 50 ohms and then the broadband transformer on the transistor output raises the impedance at this end of the circuit back to the normal 50 ohms. A broadband transformer typically consists of just a few turns of wire on a torroid core, with the primary and secondary windings either twisted together or wound together as a bifilar pair.
Such atransformer, being broadband, can operate over a wide frequency range. If this range is designed to cover a number of amateur bands, such as from 3-30MHz, and the drive circuits also designed similarly, then the transmitter itself becomes broadband and apart from the VFO, requires no bandswitching or re- tuning.
One major problem of such adesign is
CforrIstr wave
Fig 6 An AM signal
that because the RF circuits are broadband, any spurious frequency or harmonics which may be generated also get amplified and appear at the output. The output must be adequately filtered therefore with the use of low-pass filters to prevent these unwanted frequencies
from reaching the antenna and being radiated. Most of today's commercial and home constructed transistor PAs use broadband techniques.
Modulation
Modulation is the term used to
describe the process of acting upon the
carrier wave produced by atransmitter in
order to transmit intelligence. This can
be speech, Morse code, avideo picture
or music. Because the carrier wave is an
ac current of constant frequency, ampli-
tude and, with respect to afixed point in
time, phase, it can be modulated by
variation of either the frequency (fre-
quency modulation or FM) or the
amplitude (amplitude modulation or
AM).
All the modulation processes produce
side frequencies, both above and below
the carrier wave, that are termed
sidebands. With amplitude modulation,
the highest sideband can be determined
by adding together the carrier frequency
and the highest frequency of the mod-
ulating signal whilst the lowest sideband
is found by subtraction. Thus the differ-
ence in frequency between the highest
sideband and the lowest sideband is
termed the bandwidth occupied by the
transmission.
To reproduce music adequately, it is
necessary to have quite a wide band-
width so that frequencies over the whole
audio range can be transmitted, but for a
communication
system
where
intelligibility is the prime factor, the
bandwidth can be considerably reduced.
For the transmission of speech then, a
bandwidth of only 5-6KHz is adequate for
an amplitude modulation transmitter as
we only need to transmit frequencies of
up to 2.5-3KHz. The audio bandwidth is
restricted by using alow-pass filter in the
transmitter's modulation circuit which
has acut-off frequency of about 2.5KHz.
Deviation For FM things become a little more
complex because, theoretically, the
sidebands in an FM system are infinitely wide. Here the carrier is known as the centre frequency, and the change in the frequency of the carrier ( which is both positive and negative) is called the
deviation. This deviation is proportional to the amplitude of the modulating signal and its limits are determined by the
MARCH 1985
BACK TO BASICS
peaks of the modulating voltage. The
rate of deviation of the carrier is equal to the frequency of the modulating signal and is unaffected by changes in the amplitude of the latter.
It is the deviation which is affected by the amplitude of the modulating signal,
and the ratio of the maximum deviation
to the highest modulating frequency is termed the deviation ratio. The relationship between the deviation and the frequency of the modulating signal is called the modulating index. For FM communication, amode known as NBFM or narrow band frequency modulation is used where the deviation is limited to ± 2.5KHz: approximately the same as for an AM transmission.
Figure 7 shows an amplitude modulated carrier wave at various levels of modulation. The modulation factor, or modulation depth, is the ratio of the modulation amplitude to the amplitude of the unmodulated carrier and can be expressed as apercentage. The shaded area is termed the modulation envelope. 100% modulation ( modulation factor of 1) is achieved when the amplitude of the modulating signal has been increased to the point where its negative peak has reduced the amplitude of the carrier to
zero, whilst its positive peak has increased the carrier amplitude to twice
the unmodulated value, as shown. Any further increase in the amplitude
RI eacillate0e
Me...1·1* envelope
oppo. SOS rneel·elm,on
Fig 7 Modulated carrier wave
100, ono/1·040...
0 -
ulat eon
of the modulating signal will result in over- modulation of the carrier and is a condition to be avoided as this causes distortion. It also introduces unwanted harmonics of the modulating signal into the transmission, making it occupy a greater bandwidth than necessary and
becoming the source of possible interference to nearby receivers as outlined last month. This is known as splatter and is asituation which must be avoided.
Overmodulation of an FM signal would simply increase the bandwidth of the transmission, making it more like FM
than NBFM. There is another mode of transmission
yet to be described: single sideband. Referring back to Figure 6we see two things. The carrier wave does not contain
any intelligence itself and the two sidebands, being identical, both carry the same intelligence. Therefore, it is possible to remove the carrier and one of
the sidebands from the signal before
transmission and still transmit all of the intelligence. This is the system known as single sideband suppressed carrier, or simply SSB.
Next month Next month we conclude modulation
and transmitters and turn our attention to power supplies. Meanwhile, make sure you are familiar with the oscillator circuits in chapter 5 of the RAE Manual and in particular the importance of frequency stability and the factors which affect it. Remember also the use of alowpass filter.
Acknowledgements and references 'Radio Amateurs' Examination Manual'G L Benbow, G3HB ( RSGB) A Guide to Amateur Radio- Pat Hawker, G3VA ( RSGB) Radio Communication Handbook (fifth edition) - RSGB City and Guilds of London Institute.
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EPROM COPIERS
The amazing SOFTY 2 The * Complete Tool' kit" for copying, wi ding, modifying and listing EPROMS of the 2516. 2716, 2532. 2732 range. Many other functions include integral keyboard, cassette interlace, serial and parallel data i/o. UHF modulator. ZIF socket etc 01(9 ( 195.00 + PP £2.30. "GANG OF EIGHT' intelligent Z80 controlled gang programmer tor ALL single 5v rail EPROMS upto 27128 Will copy 8 27128 in tYP ONLY 3 MINUTES'. Internal LCD display and checking routines for IDIOT PROOF Operation ONLY £395.00 + PPE.1.043.
"GANG OF EIGHT PLUS" same spec as above but with additional RS232 serial inter 61l..a..ce for down line loading data from computer etc 05(95445.00 + PP 13.00.
Data sheets on request.
DATA MODEMS
Join the communications revolution with our super range of DATA MODEMS with prices and types to suit all applications and budgets!' Most modems are EX BRITISH TELECOM and are made to the highest standard for continuous use and reliability. RS232 interfaces are standard to all our modems, so will connect to ANY micro etc. with an RS232 Serial interface.
DATEL 26 see SPECIAL OFFER centre of this ad. MODEM 13A, 300 baud. Compact unit only 2 high and same size as telephone base. Standard CCITT tones. CALL mode Only. Tested with data. 91119145.00 + 90 (950, MODEM 20-1, 75-1200 baud. Compact unit for use as subscriber end to PRESTEL, MICRONET or TELECOM GOLD. Tested with data. £39.95 + PP Ea 30 MODEM 20-2 same as 20-1 but 1200-75 baud £1400. TRANSOATA 307A. 300 baud acoustic coupler Brand new with RS232 interface. moo + n(4.50 DACOM DSL2123 Multi Standard Modem. switchable CCITT or USA BELL 103 standard. V21 300-300. V23 75-1200. V23 1200-75 or 1200.1200 half duplex. Auto answer via MODEM or CPU. CALL or ANSWER modes plus LED status indication. Dim 2.5 a8.5 x9 BRAND NEW fully guaranteed ONLY Flft 00 + 99 Es». DATEL 2412 Made by SE LABS for BT this two part unit is for synchronous data links at 1200 or 2400 baud using 2780/3780 protocol. Many features include Auto answer. 2or 4 wire working,etc. etc. COST OVER nee. 055151ff (183.00. DATEL 4800, RACAL MPS4800 Non speed
good condition [588.00 MR 810.00
SPECIAL 300 BAUD M hf
Another GIGANTIC purchase of these EX BRITISH TELECOM, BRAND NEW or little used 2B data modems allows US to make the FINAL REDUCTION, and for YOU to join the exciting world of data communications at an UNHEARD OF PRICE OF ONLY £ 29.95. Made to the highest POST OFFICE APPROVED spec at acost of hundreds of
pounds each, the 28 has all the standard requirements for data base,
business or hobby communications. All this and more!'
· 300 baud full duplex· CALL. ANSWER and AUTO modes · Full remote control ,,,,,eitNirt,"4104 · Standard RS232 serial interlace
· CCITT tone standards ..e NOW Olillie · Built in test switching · Supplied with full data £ 29,515 · 240v Mains operation
· Modular construction
---",
x..-. · 1year full guarantee
· Direct isolated connect ,,i ,von · Just 2 wires to comms. line
Order now - while stocks last. Carriage and Ins. £ 10.00
¡AV .,e£250
SUPER PRINTER SCOOP
ORAN() NEW TM ' Do Everything Printer' at apree that will NEVER be repeated Standard CENTRONICS CENTRONICS parallel entedeC· for Piglet connection to NW, 0111C, DRAGON etc Superb print duaYty win full 739-2 pin addrosaapit graphics and 4ype fonts plus
MON DEFINITION ' internal PROPORTIONAL SPACED
MOD( to, WORD PROCESSOR applications 60-132 Columns, engle sheet, sprocket cv roil paper handling plus
such more Available ONLY from DtopsAy ELEcritoestas
at the macula,' tinge of mar arosse + VAT Cons:441e with tall manual etc Limited quantity -Hurry while MOCKS last
Options, Interface cal» ( specify) for BBC. ORIC DRAGON or CENTRONICS 3e way pig £ 12 50 Spire ribbon £350 each BBC graphics screen dump utility program Cato
Come» and ins £ 10oo. vAT
HUNDREDS OF PRINTERS EX STOCK FROM £49.00. Call Sales Office for Details.
BUDGET RANGE
VIDEO MONITORS
At a price YOU can afford, our range of EX EQUIPMENT video monitors defy competition ,'All are for 240v working with
standard composite video input Units are
pre tested and set for up to 80 col use on
BBC micro. Even where MINOR screen
burns MAY exist .- normal data displays are
unaffected 1000s SOW TO DATE
12" KGM 320-321. high bandwidth input,
will display up to 132 columns x25 lines
p/Vi £32.95 Housed in attractive fully enclosed
brushed alloy case
only
GREEN screenE39.
24" KGM large screen black 8 white monitor fully enclosed in light alloy case
Iiiieal.Kh_d_ola,_.>hops. clubs etc
UNL V£33 -Ug Carriage £ 10.00
II STOCK -
DEC CORNER
PDP 1140 System comprising of CPU. 124K memory + MMU 16 line RS232
interface. RPO2 40 MB hard disk drive.
TU10 9 track 800 BPI Mag tape drive, dua.
rack system, VT52 VDU etc. etc. Tested
and ru tning00
£3750.
BA11 MB 3.5" Box. PSU, LTC
DHin11-ADe16 x RS232 DMA interlace
DLV11-J 4 xEIA interface
ou pli Sych. Serial data i/o
£385.00
£2100.00 £310.00 Mum
1only large CALCOM P1036 AO 3pen drum plotter and offline 915 magtape controller. Good working order.
£2500.00.
DISK DRIVE SPECIALS
SIEMENS F00-100-5 51 /4 "40 track single sided. Ex new equipment tested,
guaranteed working. Complete with data £75.00
SHUGART SA400 51 /4 "35 track, single sided, Ex equipment, guaranteed
working £55.00
SHUGART SABCO, SA850 8" drives plus spares EX Stock call for prices
Hard disk drives.
Large quantities of HARD DISK drives currently EX STOCK including:
DRE series 30 mb Front Load for DEC NOVA etc
PROM £395.00
DIABLO 44/ORE 4000 A, B 5+5 mb cartridge drive
FROM [ MOO
CDC HAWK 5+5 mb cartridge drive as new condition
CDC 9782 80 mb DEC RM03 compatible
FROM £795.00 FROM £2900.00
PE RTEC 03422 5+5 cartridge drive
FROM £ 95.00
Large quantities of spares and controllers available for S100. DEC. HONEYWELL,
DATA GENERAL. Call sales office for details.
IN HOUSE disk drive refurbishing service - call for competitive quotations"
ADO VAT TO ALL PRICES
00c2on0tr0olDlielrog - multi P1<
£495.00
DZ11-B 8 line RS232 mus board £650.00
LA36 Decwriter EIA or 20 ma loop £270.00
LAXX-NW LA180 RS232 serial interface
and butter option £
LAX34-AL LA34 tractor feed
MS11·Jr, Unibus 32 kb Ram
££ 88 05 .°0° 0
MS11-LB Unibus 128 kb Ram £ 450.00
MS11-LO Unibus 256 kb Ram £850.00
MSC4804 Obus (Equiv MSV 11- 1-1
256 kb
£499.00
PDP11/05 Cpu, Ram, i/o, etc PDP11/40 Cpu, 124k MMU
£450.00 £1850.00
RT11 ver. 3B documentation k.t £70.00
RK05-J 2.5 Mb disk drives KU3JA POP 8async i/o MUM PDP 8 Bootstrap option
££ 61755°..002
£75.00
VT50 VDU and Keyboard -
current lOOP
£175.00
VT52 VDU with RS232 interface £35600
1000's of EX STOCK spares for DEC
PDP13, POKIA, PDP11 systems & peripherals. Call for details. All types of
Computer equipment and spares wanted for PROMPT CASH PAYMENT.
e.
S £1.00. All prices quoted are for U.K Mainland, paid cash with order in Pounds Sterling PLUS VAT. Minimum order value
Minimum CreditCard orderEl0.00. Minimum BONA FIDE account ordersfrom Government Depts,,Schools, Universitiesend established companiesn0.00. Where post and packing not indicated please ADD £ 1.00 + VAT. Warehouse open Mon- Fri
9.30-5.30. Sat 10.30-5.30. We reserve the right to change prices and specifications without notice. Trade, Bulk and Export
e
rf- TO Cif./ f
32 Sirloin Way Upper Norwood London SEI
XF
I- II\ Ls;
Telephone O1 6/9 4414 Telex 27924
MARCH 1985
please mention AMATEUR RADIO when replying to any advertisement
51
PHONE
0474 813225 3 LINES
P.M. COMPONENTS LTD
DEPT AR SELECTRON HOUSE, WROTHAM ROAD MEOPHAM GREEN, MEOPHAM, KENT DA13 OQY
TELEX
966371 PM COMP
INTEGRATED CIRCUITS
AN124
2.50
462140 2.50
66239
2.30
AN240P 2.80
AN264
2.50
66612
2.15
AN362L 2.50
AN7140 3.50
AN7145 3.50
AN7145M 3.06
AN7150 2.96
BA521
3.36
CAI352E 1.75
CA3086 0.44
CA3123E 1.96
CA3140T 1.18
0713015 2.50
HA1339A 2.05
(141366W 3.78
1161377 3.50
1441156W 1.90
861551 2.66
LA1230 1.15
LA4102 2.«
LA4140 2.96
LA4031P 1.80
LA4140 2.90
LA4461 3.96
LA4250 2.65
LA4420 1.10
LA4430 2.80
LA4400 4.15
LA4422 2.60
LA4461 3.96
LC7120 3.25
LC7130 3.50
LLC7131 5.50
LC7137 6.50
LA11011 3.15
LM3246 0.43
LM38068 1.60
LM38068 9.75
1.451513L 2.30 M5155L 2.95 M51521 L 1.50 3.483712 2.00
54133756 2.50 MC 1307P 1.00 MC1310P 1.96 MC1327 0.98
MCI1270 0·21
MC1330P 1.10
MC1349P 1.20 MC1350P 0.66
MC1349P 1.20
MC1350P 0.95
MC1351P 1.30 MCI 357 2.35
MC1358 MC1495
8.58 3.00
MC1496 1.25
MC145106P
7.95 MC 1723 0.50
MC3357 2.75
MC3401L 2.50 M L23IB 1.75
ML232B 2.50 MSM5807 5.75
PL L024 5.75
SAA5004 3.50
SAA1025 7.25
SA45010 6.35 SAS560S 1.75
SAS570S 1.75
SAS580 2.85 SA/SB/T/U
1.0c
01.90161 SL9178 S11310
4.85 6.65 1.80
SL1327
1.10
SL 13270 1.10
S6 76053N 1.95 SN76013N 1.93 S6 76023N 1.93
SN760336 1.95
SN76110N 0.89
SN 761156 1.25 S676131 1.30
SN762260N
0.95 SN762276 1.05
SN 76533N 1.66
S6765446 1.95 5676570N 1.00
SN76650N 1.15
SN766606 0.90
STK014 STK015 010043
7.93 5.93 9.30
SEMICONDUCTORS
44912 AC126 AC127
AC128 AC128K AC141 AC141K AC142K AC176 AC176K AC187 AC187K AC188 AC188K AD 142 AD143 AD149 40161 AD 162 ADI61/2
AFI06 AF114
AF121 AF124 AF125 AF126 AF127
AF139 AF150 AF178 AF239 AU106 AU107
AU110 AY102
BC1074 BC1078 BC108
BC1084 BC1086 BC109 BC 1098 BC109C BC1144 BC1164 BC117 BC119 BCI 25 8C139 BCI 40 BC14I
8C142 BC143 BC1474 BC 1478
BC1484 BC148B BC149 BC153 BC157 BC158 BC159 BCI 60 BC161 BC 1708 13C171 BCI 714 BC17IB
BC172 BC17213 BC172C
BC173B
BC174 BC1744 BC177
0.25 0.46 0.20 0.28 0.33 0.28 0.34 0.30 0.22 0.31 0.25
0.26 0.25 0.22 0.79 0.02 0.70 0.39 0.39
0.80 0.20 1.66 0.80 0.65
0.36 0.32 0.94 0.40 0.00 1.96 0.42 4.50 3.60 2.00 2.« 0.11
0.11 0.10 0.11 0.12 0.10 0.12 0.12 0.00 0.15 0.110 0.24 0.25 0.20 0.31 0.25 0.21
0.24 0.09 0.09 0.09 0.09 0.09 0.30 0.12 0.09 0.09 0.28 0.29 0.15 0.00 0.10
o.to 010 0.10 0.10
0.10
0.06 0.09
0.16
13C178
0.1 5
BC182
0.10
BCI82LB 0.10
BC183
0.10
BC183L 0.09
BC184LB 0.09
BC204
0.10
13C2079 0.13
BC208B 0.13
BC2I 2 0.09
BC2I2L 0.09
BC212LA 0.09
BC213
0.09
BC213L 0.09
BC214
0.09
BC2I4C 0.09
BC214L 0.09
BC237B 0.09
BC238
0.09
BC239
0.12
BC2514 0.12
13C2524 0.15
BC258
0.25
BC2584 0.39
BC284
0.30
BC300
0.30
BC301
0.30
BC303
0.25
13C3078 0.09
8C327
0.10
BC328
0.10
BC337
0.10
BC338
0.09
BC3474 0.13
13C461
0.35
BC478
0.20
BC527
0.20
BC547
0.10
8C548
0.10
8C5494 0.10
BC550
0.14
BC557
0.08
BC5578 0.08
BC558
0.10
BC639/10 0.30
BCY334 1.80
80115
0.30
80116
0.60
(301241, 0.39
130131
0.42
BD132
0.42
(30133
0.40
80135
0.30
90136
0.30
90137
0.32
90138
0.30
90139
0.32
60140
0.30
90144
1.10
130150C 0.29
90159
0.33
90160
1.50
80166
0.53
80179
0.72
80182
0.70
80201
0.83
90202
0.65
130203
0.78
80204
0.70
80222
0.46
90223
0.59
80225
0.48
BC232
0.35
913233
0.35
80234
0.35
80236
0.49
STK4I5 7.93
ST6433 3.95
STK435 S16437
7.95 7.95
ST 6439 7.95
STK461 11.50
TA70616P 1.50 1'47108P 1.50
TA7120P 1.55 TA7129P 2.54
TA7130P 1.50
747137P 1.00
147146 3.95 TA 7I76A P 2.93
TA7193P 3.95
147203 2.95 TA7204P 2.15
TA7205AP 1.1 TA7222AP 1.3
TA7227P 4.2
TA7310P 1.6
TA7313AP 2.9
TA7314P 2.9 TA7137P 1.03
TA7314P 2.9.5
TA7321P 2.25 747609P 3.15
TA7611AP 2.95
TAA550 0.25 TAA570 1.95 TAA6618 1.20
TAA700 1.70
TBAI2OAS 8
C TBA23I TBA395
1.00 1.25 1.50
TBA396 0.75
T15644011 2.55
1864500 1.25 TBA510 2.50
TBA5100 2.50
TBA520 1.10 1E445200 1.10
TBA530 1.10
TBA5300 1.10 TBA540 1.25
7845400 1.35
TI345500 1.95
TBA560C 1.45 T865600 1.45 TBA570 1.0C
TBA7500 2.65
TBA800 0.89
T84810461.445 TBA810P 118
734620M 0.78
TBA13200 1.45
TBA890 TBA920
2.50 1.411
TBA95CV2X 2.34
TE14990 1.45
TBA9500 1.44
TCA270 1.10 TC427060
1.10
TCA650 TCA800
2.50 2.94
TC48306 1.96 TC4900 2.50
TCA940 1.44
TDA440 2.20
TDA1001 1.96
T0410024 1.945 7041003A 3.941
T0410044 3.25
TDA10064 2.50 TDA1010 2.15
1061055 2.50
7041037 1.96 1041044 2.15 1061170 1.96
TDA1190 2.15
104127003.96
TDA1327 TDA2002 1062053
1.70 1.94 2.95
TDA2010 1.96
TDA2O2O 2.98
1062030 2.60 TDA2140 3.96
TDA2151 1.96
TDA2160 2.50 1042190 2.96
TDA252I 3.25
100.2522 1.06 TDA2523 2.95
TDA2524 1.06
1042530 1.05
TDA2532 1.96 TDA2540 1.96 9 TDA2541 2.15
130237 80238 B0242
80246 80376 6113410
80434 90437
BID438 B0520 813538 130597 80701 130702 80707
80X32 00757
8E115 8E119 8E127
13E154 8E158 9E160 8E167 61E173 8E177 13E178 8F1 79 8F 80 8F181 9E182 13E183 9E164 8E185 8E194 13E195
13E196 BF197
9E198 BF199 8E200 8E241 13E245 8E257 9E258 13E259 BF271 9E273 0E336 BF337
61E338 13E355 9E362 9E363
8E371 13E394 8E422 BF423
0.40 0.40 0.45 0.78 0.32 0.66 0.66 0.73 0.75 0.65 0.65 0.95 1.25 1.25 0.90 1.60 1.0.5
0.35 0.65
0.39 0.20
0.22 0.27 0.27 0.22 0.38 0.28 0.34 0.29 0.29 0.29 0.29 0.28 0.28 0.11 0.11 0.11 0.11 0.19 0.14 0.40 0.15 0.30 0.23
0.25 0.218 0.28 0.18 0.34 0-29 032 0.37
0.38 0.68 0.28 0.19 0.32 0.25
9E457 9E458 13E467 9E595 FIF597
BFR39 BER40 BER41 BF1181
BER88 BMW) BFR91 13E742 BF743
BFW61
0.33 0.36 0.68 0.23 0.25 0.23 0.23 0.28 0.23 0.30 1.30 1.75 0.35 0.35 0.60
BFW92 0.85
BF X29
0.30
BFX84
0.26
BFX85
0.32
BFX86
0.30
BFX88
0.25
8E950
0.21
8E951
0.21
8E952
0.25
8E990
0.77
BLY.113
1.75
BRICA
0.26
139101
0.49
88103
0.55
99303
0.95
BRC4443 1.13
87100A/020.95
131106
1.49
81116
1.20
81119
3.15
81120
1.65
BU105
1.22
BU108
1.69
BUI24
1.23
BUI25
1.23
8U126
1.60
BU204
1.53
BU205
1.30
BU208
1.39
BUTO8A 1.52
BU2080 1.85
BU326
1.20
13U3260 1.30
BU407
1.24
BU500
2.25
BU526
1.90
BU807
2.25
BUY20 2.15
BUY69B 1.70
M33000 1.90
MJE340 0.40
MJE 350
MJE520 0.48
MJE2955
MPSA13 0.29
MPS492 0.30
MRF237 3.45
MR F4506
12.50
MRF453 17.50
MRF454 23.50
MRF475 2.50
MRF477 10.00
OC16W 1.95
0C23
1.50
0C29
2.25
0C36
2.25
0C42
0.55
0C44
0.75
0C45
0.55
OC70
0.45
0071
0.55
0075
0.95
0081
0.50
OC 16W 9200813
2.30 1.70
92010E1 1.70
R2322
0.58
R2323
0.84
R2540
2.48
9C616334 0.90
RCA 16335 COO
0206013 0.95
SK E5F
1.4.5
TIP29
0.40
TIP29C 0.42
TDA2560 10.42571
T042571
2.15 1.96
2.05
NEW BRANDED CATHODE RAY TUBES- Pt.... snow additional VI pro tube Ay Amine
TDA258I 2.25
TDA2582 2.95 TDA2593 2.95
TDA2600 5.50
TDA2610 2.50
T0426114 1.95
T042640 2.60
TDA26806 2.75 TDA2690 2.45
1063310 2.95
TDA4600 2.50 1049503 3.15
TDA3560 3.95 7E41009 1.35 UPC566H 2.95 uPC575C2 2.75
UPC102511 1.95
UPC102831
1.95 UPC10321/
1.50
UPC1156H
2.75
UPC1158M
0.75
UPC 1167C2
1.15 UPC 1181
1.25 UPC1182H
2.95 UPC1185H
3.95
UPC 119IV 1.50 UPC1350C
2.95 UPC I353C
2.45
UPC1365C 3.95
UPC 2002H 1.95
555
0.35
556
0.42
723
0.50
741
0.35
747
0.50
748
0.35
'808 7805 78,5
0.60 0.65 0.65
TIP30C TIP31C
TIP32C TIP33B TIP3413
11P413 TIP41C TIP42C TIP47
0.43 0.83
0.42 0.95 0.06
0.46 0.45 0.47 0.63
A1865/20 AW36 11 CME822W
CME822GH CA1E14211GH CIAE14213W C1.4E152304
CME1523W CA4E1431031 CIAE1431W
CME2CQGH C134E2024W CME2325W CME3126GH CME3128GH CM 93128W CME3132GH CME3155W CRE1400 CV429 CV1450
CV1526 CV2185
CV2191 CV2I93 CV5119
CV5320 CVX389 09-110031
09-120 D10-2100k D10-210014688 CHO-2100H 72 010-2300H 010-230GM 010/29309/90 013-300H D13-33051 D13-47011/26
D13-47031/34 D13-47014
013-51G /126 D13-51GM/26 013-4500H/01 D13-471011/243 013-5500H 1313-6000M O13-610GH 1313-6100M 013-6110H 013-6110M D1'1, 30GH 014-120G Hoe D14- 15001-I 1314-1500M 014-1720H/84 014-172GR
1314.1720V O14-1730H
014-1730M 014-1730R 014-1810H/62 014-1810H/98 014.1810J 014-1810M
TIP120 TIP125 TIP142
TIP146
TIP161 TIP2955 TIP3055
0.50 014-1810M50
0.63 014-1820H
1.75 1314.1820M/98
2.75 2.68
014-20013E 014-2000A/50
0.80 I 014-200GM
0.66 014-2100H
TIS91
0.20
65.011 25.015 19.06 25.00 44.« 30.00 39.00 36.00 29.00 30.00 46.00 MI.« 44.00 45.00 «GO 46.00 45.00 45.00 25.00 99.00
36.00 19.« 15.« 19.00
15.00 06.00 46.00 «GO 39.50 46.00 45.00 66.00 66.00 34.00 35.00 56.00 49.60 40.00
55.00 55.00 56.00
65.00 88.00
56.00 58.00 65.00 59.00 59.00 59.00 39.00 59.00 69.00 66.00 79.00 76.00 69.00 55.00 85.00 55.00 53.00 55.00 65.00 65.00 moo 33.00 59.00 50.00 55.00 09.00 68.00 76.00 75.00
D14-270GH ,50
014-310W 1314-3200H 014-3200H/82
O14-340G H/KM O14-3401(A D16- 100G H O16.1006H/65 016-1000H/67 016-100031674 016-1000H/79
016-1000H796 D1310061-197 O18-1600H 021-10GH 1321-1003 021-1OLD
DB7 36 DB7 36 DG7 5 DG7 32 DH3 91 0H7 91 DP7 5
0P7 6 DN13 78
F15-101LC F16-101GM F16-101LD F21-131309 F21-130LC F21-131GR F31-10GM F31-10GR F31-10LC
F31-1OLD F31- I2LC F31- 12L0 F31-13GR F31.1340 F31-131.0
F41.123LC F41.141LG F41-I42LC M7- 120W M14.100GM
M14-100KA M14 100LC M17.1510VR M17-151GR M19-10009 M19-101GR M19- 103W M23-110GH
M23- 111W M23-111GH M23-11ILD
M23-112GM M23- 1120V M23-112GW M23-112KA
M23-112LD M23- 1121N M24-120GM M24-12009
M24-120LC M24-120WAR M24.121GH M24-12ILC M24-121WA
M213.12GH M28- I2LC M28-13LC
75.00
110.00 50.00 88.00
48.00 46.00 158.00 69.00 66.00 75.00 69.00
75.00 65.00 69.00 58.00 69.00 69.00
35.00 55.00 56.00 45.00 53.00 45.00 35.00
38.00 35.00
49.00 68.00 55.00 115.00 58.00 79.00 53.00 65.00 65.430
56.00 615.00 60.00 63.00 65.00 66.00
180.00 160.00 135.33
19.00 45.00
65.00 48.00 175.00 175.00 98.00 35.00 55.00 56.00
85.00 55.00 38.00
55.00 56.00 36.00 56.00
55.00 55.00 89.00 59.00
59.00 59 .00 55 .00 59 .00 31500
5590 55.00 « Lop
M28- 13L0
M28-1308 M28-13109 M213- 1320M
M213-133GH M31-100GH M31-101GH M31.182011 M31-182GV M31- 183W M31- 184W
5131-1540H M31.184P31 M31-1Ct5GHNR 5131-186W M31- 19001-I M31.190GR
5131-190LA 5131-190W M31-191GH M31-19109 5131-1910V 5131-191W M31- 192W
M31-195GH M31-210GH
M31- 220W M31-27009 M31-271 P31 M31-271GW 5131-271W M36- 12W M36- 141L.8 M36- 141L0 M6- 141W
1436-170L0 M38-10309 M38- 120W M38-120WA M38-121011 5438-121GHR
M38- 12I LA M313- 121W6 M38.1220W 1438-140LA M38-141LA
M38-14208 5138-142LA M38- 340P31 1,438-3410R M38- 341P31 M38- 344P39 M40-12013/ M43- 120M/01
M43-12LG/01 M44-120LC M44-120GR
5147-2509/22 1.450-120G H M50.120011 M50.120GV
M50-120LC M61-120LC 3.161-120W 5668
SE4/D-P7 SE42BP31AL SE4213P31 SE52AP31AL SE5Fp31
7937 1948N 1948H
49.00 V3191
50.00
49.00 V4150LC
56.00
56.00 V4254E1
65.00
35.00 V4274GH
84.00
56.00 V42831.1/ 56.00 V5002L D
06.00 ».00
55.00 0500408
51300
65.00 V5034LD
60.00
53.00 V8001GH
66.00
56.00 V6006GH
85.00
68.00 V6007t3P31
60.00
66.00 V60070W
05.00
66.00 V6008G H
59.00
00.00 V6008W
06.00
60.00 V6034WA
55.00
66.00 V604C LA
60.00
56.00 V6048F
66.00
515.00 760483
40.00
69.00 V6052GH
95.00
59.00 V6052GR 69.00 V60648 LA
95.00 68.00
56.00 V6064BP31
65.00
59.00 V6064C LA
55.00
59.00 V6069GH
55.00
50.00 V6070P31
48.00
80.00 070166
96.00
30.00 V7030
59.00
65.00 V7031GH » AO
64.00 1/7931/676
60.00
66.00 V70356
40.00
66.00 V7CG7GH
44.00
75.00 V813040F1
65.1313
75.00 V5036GH 75.00 V80106
46.00 66.00
75.012 ,
0.1»
75.00
13.60
65.00, 4EP1
30.00
314/0BM
°AAA 3WP1
51.00 10.50
66.00 5BP1
9.00
65.00 58HP1
30.00
66.00 5BHPIFF
30.00
65.00 513HP31
30.00
65.00 SCPI
10.00
65.00 6EP7/5
30.00
65.00 13BP1
13.50
66.00 1381,4
17.60
65.00 170WP4 66.00 323/1055
26.00 09.00
68.00 880/8813/890/89L
16.00
68.00 66.00 50.00
1273
1564 1844
39.00
34.00 46.00
65.00 554510 M
76.00
68.00 9442E1
60.00
64.00 954470M
76.00
66.00 95449
75.00
65.043 7709631
70.10
86.00
66.00 66.00
54.00 75.00 75.00
TAPE NUM
Mono Head Auto Reverse Stereo Head
1.60 3.50 2.06
45.00
45.00
35.00 18.8C712047P11CJU. 55.00 9677M
22.00
55.00 P4231BAM 58.00 XP1002
19_00 29.00
68.00 XP1117M 154.00 XP42040
24.00 35.00
66.00 95241-I
26.00
13/190/2 1.60 ZRF0112 16.60
DIODES
BASES
W1REWOUND REMSTORS
261100 261711 262219
262905 263063 263054 263055 263702 263703 2637134 263705 263706 2637013
263733 263773 263792
2344280 264427 264444 265294 265296 265298 265496
6.50 0.30 0.29
0.40 0.40 0.80 0.82 0.12 0.12 0.12 0.12 0.12 0.12.
9.50 2.75 1.38
3.50 1.98 1.15 0.42 0.48 0.80 0.06
AA119
0.08
BA115
0.13
80.145
0.16
BA148
0.17
BA154
0.06
BA156
0.15
BA157
0.30
SAX13
0.04
BA)(16
0.06
EIB10513 0.30
81151
0.79
87126
0.10
67127 59133
0.11 0.15
59164
0.45
57176
1.20
57179
0.53
59182
0.55
87184
0.35
50199
0.413
09206
0.14
B9208-800 9.33
137210-800 0.33
57223
0.90
137298A00 0.22
B7299-8000.22
87010
0.20
87536-150R
0.20
B7038-6009
0.60 BYX55-6000.30
BYX71-6001.110
BZ561
0.15
52788
0.10
B2795C30 0.35
CS4B
4.50
CS105
8.45
OA47
0.01)
0A90
0.05
0A91
0.06
0A95
0.06
OA202
0.10
162109 2.93
6235
623C 623EP N23WE 64001 N4003 64004 64005 64007 64148
64448 65401
65402 65403 65406 65407 65408 1144
1923
12002
2.95
2.95 2.95 2.95 0.04 0.04 0.05 0.05 0.00 0.02
0.10 0.12
0.14 0.12 0.13 0.16 0.16 0.04 0.15
0.10
B50 B7G
8.50 0.28
1370 SKTD0.28
880 B8H
0.36 0.70
596
1.50
B9ASKTD 0.40
890
0.75
6108
0.20
6138
0.60
B14A
3.00
12 Pm CRT
0.99
NuvIstor 2.95
Octal
0.38
SK610 35.00
UX5
1.76
UX7
1.76
Valve Can 0.30 8%011 0.14
14 P,r, 0,1 0.16
16 Pm Ehl 0.17
18 Ffin Del 0.10
4Watt 2R4- 10K 7Watt 947-22K
11 Well 195-15K 17 Watt1R-15K
0.20
0.20
0.25 0.30
ZENEFI DIODES BZX81 0.15
6V2 7V5 8V2 9V1 10V 11V 12V 13V 15V 16V 18V 20V 22V 24V 27V 30V 33V 36V 39V 47V 51V 56V 68V 75V
TNERMISTORS
0.23
VA1056S
0.23
VA1104
0.70
VAT8650
0.46
VA1097
0.25
BZY88 0.07
2V7 3V 3V3 3V6 3V9 4V3 4V7 5V1 5V6 6V2 6V8 7V5 6V2 9V1 10V 11V 12V 13V 15V 18V 20V 24V 27V 30V
BATTERIES
7V Power ?vitae batten es
18175 92 25 ea other pnces on
request
256329 0.05
254715 0.60 2SC495 0-80 2SC496 0.80 25C931 0 0.96 25C1C96 0.40 2SC1108 2.50
25C 11729 2.20 25C1173 1.15
2SC1306 1.00 2SC1307 1.50 25C1364 0.50 25C1449 0.50 2SC16713 1.25 2SC 1909 1.45 25C1945 2.68 25C1953 0.96 2SC1957 0.80 2SC1969 1.06 25C2028 1.15 25C2029 1.165 25C2078 1.45 25C2091 0.55
2SC 2098 2.95
LINE OUTPUT TRANSFORMERS DECCA 100 DECCA 1700 MONO DECCA 1730 DECCA 2230 GEC 2040 GRUNDIG 1500 GRUNDIG 5010-6010 2222 5011-6011 ITT CVC20 ITT CVC30
PHILIPS G8 PHILIPS C9 PHIL IPS G11 P7E 725 RBM 720A TANDBERGE 90 TELEFUNKEN 71IA THORN 1590 THORN 8000
THORN 9000 THORN 9800 THORN MAINS
7.95 9.95 8.95 8.25 8.93 13.43
13.45 8.20 8.23 8.50 8.99
13.39 10.93 12.40 11.15 11.15
9.50 9.20 9.95 22.40
ENT MULTIPUERS ITT CVC20 ITT CVC30 PHIL IFS 08 550 RANK 720A THORN 3000/3500
THORN 8500
THORN 9000 UNIVERSAL TRIPLER
5.35 6.35 6.06 6.91 7.57 5.50 8.00 5.45
REPLACEMENT ELECTROLYTIC
CAPACITORS
DECCA 30 ¡ 400-400 350V,
2.85
DECCA 801001400350V)
2.99
DECCA 1700 IMO- 200-400-350V 3.55
GEC 2110(600.300V)
2.25
TT CVC2012213/400V)
1 80
PH IL IPS 08(600/300V)
2.25
PHIL IPS 091220063VI
1.19
PHIL IPS GII ( 470 250V)
2.35
POTENTIOMETERS
SPARES& AIDS
FOAM CLEANSER
0.70
FREZE IT SOL DA MOP
0212
044
SWITCH CLEANER
0.79
W040
1.25
PUSH PUSH MAINS SWITCH
(DECCA GEC RANK THORN
ETC)
1.02
P99 IF GAIN MODULE
5.00
ANODE CAP ( 27KV)
0.40
PUSH 01/170N UNITS
DECCA ITT CVC20 6WAY
7.«
ITT CvCs 7WAY
0.19
PHILIPS G81550)6 WAY
14.49
VAR/CAP TUNERS ELC1043/05 MuL LARD ELC1043106MULLARD U321
U322
8.65 8.65 8.25 8.25
20C2166 1.96
TRANSFORMER 3000 ,3500
9.70
STANDARD VERTICAL POTS 0.12
25C2314
25C2371 25C9310 ISO234 250325E 36211
3SK8/3
0.80
0.36 0.06 0.80 1.66 1.96
0.55
SOLDERING EQUIPMENT
25W Ante xI. ,
4.59
Weller Instant Moat (3,,240V Weller Marsrnan
11.30 4.74
1,21(do Solder 60/40
6.95
MIN VERTICAL POTS
0.12
STANDARD HORIZONTAL POTS
0.12
MIN HORIZONTAL POTS
0.12
CONVERGENCE PRE-SETS 0.30
SLIDERS LOG SL IDER1 INEAR
0.48 0.48
20808 A1411 SURGE FUSES
100MA-800MA
ISpeach
1A-5AMP
1290066
20M111 QUICK BLOW FUSES
100MA
8p ·//oh
200MA-5AMP
5p each
52
please mention AMATEUR RADIO when replying to any advertisement
MARCH 1985
PHONE
0474 813225 3 LINES
P.M. COMPONENTS LTD
DEPT AR SELECTRON HOUSE, WROTHAM ROAD MEOPHAM GREEN, MEOPHAM, KENT DA13 OQY
TELEX 966371
PM COMP
A SELECTION FROM OUR STOCK OF BRANDED VALVES
A1714 11.50
A1996 1140
A2087 1150
A213I 14.98
A2293 A2426
5.50 29.80
A2599 37.80
A2792 27.60
A29:13 11.40
A3012 24.00 4328324.00
0841 (891
EBC33 EBC41
EBC81 EBC90 EBC91 0691 ER F60 06083
06085
3.64 0.36 2.60 1.96 1.50 0.90 0.60 0.00 0.64 0.66 0.96
AC/TH1 4.00
06089
0.70
ACT22 66.76
AC/S2 PEN
8.60
AH221 38.00
AH238 39.00
AL60
6.00
AN 1
14.00
EBF93 0611 EBL21 EC52
EC70
EC80 EC8I
0.66 180 2.00 0.75 1.78 9.80 7.66
ARP12 ARP34
AFIP35 ATP4 AX50 AZ11
0.70 1.28
2.00 2.50 5.150 4.50
EC86 EC88 EC90 EC91
EC92 EC93
1.00 1.00 1.10 5.60 1.76 1.60
AZ31 BL63
65450 85810
2.60 2.00
67.00 66.00
EC95 EC97 EC8010 ECC32
7.00 1.10
12.00 3.110
65814 58.00
ECC33 3.60
C1K
C3JA OEA C1112G
10.00
21.00 9.00
70.00
FCC35
3.50
ECC81
1.16
ECC81 Specost
quallty
1A6
C1106 54.96 C1134 32.00 C11484 115.00
ECC82 ECC412 lard
OAS Mul1.80
C1119/1
ECC82
130.00
PhIlops 1.96
C1150/1
ECC83 0.56
138.00
ECC83
8n-
C1534 32.00
mar
1.38
CC A CC3L
2.00 0.90
ECC83 PhIllps
1.95
CL33
2.00
ECC84
0.50
CV Nos Pnces On request
ECC85 ECG*
0.60 2.75
063
1.20
ECC88 0./141
DA4I
22.50
ECC91
2.00
0442
17.60
ECC180 0.72
13490
4.50
DA100 126.00
DAF9I
0.45
ECC189 0.78 ECCEIOIS 3.50 ECC803S 3.80
DAF91
0.70
ECC804 0.50
DAF96
1.00
EC C2000 12.00
DC70
1.76
DC90
1.20
DC X4-1000
12.00
ECF80 ECF82 ECF86 ECF200
1.15 1.10 2.26 145
OCX4-5000
EC F202 114
26.00
ECF1301 0.56
0E716 DETI6 DET23
25.50 25.80 35.00
ECF804 ECF805 ECF806
4.00 2.50 10.25
DET24 31.00
ECH3
2.60
00125 22.00
ECH4
3.00
OF91
0.70
ECH35
3.00
13F92
0.60
ECH42
1.00
DF96
DF97 0863
0.68
1.00 1.20
00-181 ECH83 ECH84
0.56 0.78 0.00
DH77
0.90
ECH2000 1.50
DH79
0.64
CL80
0.80
D11149
DK9I DK92
2.00
0.90 1.20
ECL82 ECL83 ECL84
0.66 2.60 0.74
DK96
2.50
ECL115
0.06
0135
2.60
ECL86
CIAO
oun DL 70 13173
1.00 2.50 2.50
ECL805 EF22
EF37A
0.09 2.50
2.00
DL91
1.60
EF39
1.10
13192 0193
0194 DL96
0.96 1.10
SAO 2.50
EFII EF42
EF50 E055
3.60 3.50
2.60 4.96
DLSIO 13.50
EF7I
1.60
DLSI6 10.00
EF72
1.20
DM70
1.96
EF73
1.00
DM160 0051
2.78 1.80
EF80 EF83
0.56 3.50
D086/87 0.48
EF85
0.60
00802
0.72
EF86
2.25
EllOCF E8OF
11.00 18.00
EF88 Special quallty 3.15
E81CC 3.16
EF89
1.60
E811
12.00
EF91
1.68
E82CC
3.50
E092
2.16
ELUCC
3.50
EF93
0.011
E63F
(MC E843C
5.80
9.60 7.96
EF94 EF95
E097
0.90 1.60
0.90
E841CC 3.60
0098
0.00
F88CC
1114mane Spec.' 5.95
EF183 (F194 E6730
0.64 0.114 1.90
090CC 7.416
EFT31
3.50
E9OF
7.96
0F732
3.50
E91F1
4.60
0E800 11.00
092CC 099F 01301. E180GC
3.68 5.99 19.06 8.50
EF8050 (F812 EFL200 EH90
13.50 0.114 1.50 0.72
E182CC 0.00
EK90
0.72
0180F
EI86F E188CC
6.50
6.110 7.60
0132 0133 E134
0.06 4.00 2.28
0280F 19.60
EL34
Mul-
E283CC 10.00
lerd/Pnlinps
E288CC 0551 E810F 01148
13.60 42.00 25.00
1.00
0136 E137
E138
4.50 1.50
9.00 4.75
(1524 0450
6.96 1.00
141 EL42
3.80 2.00
0476
1.95
EL81
6.95
09 19
1.08
" 0182
0.58
EAA9I
0.110
0183
6.96
EABC80 0.70
0184
0.76
EAC91 00142
2.80 1.20
EL83 E 86
4.50 0.68
EAF801 2.00
EL 90
1.50
E634
1.60
2191
6.00
0195
0.70
EL113 12.15
EL 183E 150
EL I83P 3.50
61360 EL500
4.75 1.40
EL501
1.40
61509
5.25
F1519
8.96
EL802
3.84
L82I
SAO
01822 12.95
EMI
9.00
1.14
0.00
01.480
0.70
06181
0.70
EMU FM85
1.65 3.96
E6487
2.60
0832
16.50
EN91
1.50
0892
4.50
ESU150 14.16
ESU872 25.00
0051
0.80
0081
2.38
EY83
1.50
EY64
5.116
E086/87 0.50
0188
0.58
E091 EY500A
8.50 1.60
E0802
0.70
EZ35
0.78
EZ40
2.76
0241
2.15
EZ80
0.78
EZ81
0.78
EZ90
1.80
F6064
2.56
FW4/800 2.96
655/1K 9.00
6180/2M 9.00
6232Mullard
3.96 6240/20 9.00
040X3110 14.00 GC108 17.60
GC100 17.60
GC10/413 17.60
GC10/4E 17.60
GC12/413 17.50
GD88W 4.00
GOT120M 6.00
6E10
9.00
GN4 GNIO
6.00 16.00
GR1OG 4.00
GS1OC 10.60
GS1OH 12.00
GS120 12.00
GT1C 14.00
GTICSIS
13.00 GTEI75M 8.00
GT0150W 1.00
GU20 38.00
GXU1 13.50
XU3 24.00 GXU5OSS
14.50
60501
1.20
60802
1.00
6230
1.00
GZ31
1.00
GZ32
1.00
6233
4.50
6234
2.15
GZ34MUL 3.96
GZ37
4.60
HAA91
1.00
HA8C80 0.90
HBC90 0.70
H8C91
040
14093
0.75
11F94
110
HK90
1.04
HL2K
3.50
HL23D0 4.00
HL 90
0.70
111.92
1.50
8133/00 310
HR2
4.00
1090
1.00
HVF12
3.00
/(3118 56.00
104/3 46.00
KT8C
7.00
KT33C
3.10
0136 0144
2.00 4.00
KT45
4.00
0761
4.00
KT63
2.00
0186 OSRAM
15.00
0166 USA 15.114
KT66 GEC
14.56
0177
Gold
bon
1044
0181
7.00
0188 USA
10.66
0788
Gold
Leon
11116
011061
2.50
KTW62 018863
2.50 2_00
KTZ63
2.00
163
1.60
1102/2K 8.96
1120/2K 12.00
LB7-20 96.00
LS9E1
5.96
4.15024 80.00
M5374 'CIAO
645143 156.00
M8079
8.00
648062
7.80
M8063 618091
3.26 7.80
649096
3.00
649096
11.00
648099
5.00
648100
5.50
M8136
7.00
648137
5.50
M8161
6.50
M8162
5.50
M8163
5.50
M8190
4.50
648195
6.50
648196
3.50
648204
5.30
648223
4.50
648224
2.00
646225
3.50
ME1401 29.50
6401402 29.50
ME1501 14.00
MH4
3.50
MHLD6 4.00
M L4
4.50
MS4B
5.50
MU14
1.50
837
12.50
878
9.83
042
0.85
042WA 1.50
043
2.50
092
0.65
082WA 1.25
0C2
2.50
0C3 ·
1.50
003
1.70
0M4
1.00
0M56
3.00
0M6
1.75
ORP43 2.60
ORP50 3.95
P61
2.50
P41
2.50
PABC8C 0.50
PC86
0.75
PC88
0.75
PC92
3.50
PC97
1.10
PC800
1.10
PC900
1.25
PCC84 0.40
PCC85 0.54
PCC88 0.70
PCC89 0.70
PCC 189 0.70
PCC805 0.70
PCC806 0.110
PCE82
0.80
PCF80
0.65
PCF82
0.60
PCF84
0.65
PCF86
1.20
PCF87
0.40
PCF200 1.80
PCF201 1.80
PC F800 0.40
PC F0101 1.35
PC F1302 0.60
PC F805 1.25
PC F806 1.00
PC F808 1.25
PCH200 1.50
PCL82
0.85
PCL133
2.50
PCL84
0.75
PCL85
0.80
PCL66
0.85
PCL800 0.80
PCL805 0150
PD500
3.50
P0510
3.65
P0825
2.00
PE N4000 2.50
F0845
3.00
P084500 3.00
PEN46 PFL200
2.00 0.95
PL21
2.50
PL36
0.95
PL38
1.50
P181
0.72
P1814
0.72
P182
0.60
P183
0.62
P184
0.78
P188
1.00
PL95
1.75
PL302
1.00
PI , ' 12.50
01109
0.85
PL500
1.10
PL504
1.15
PL508
1.75
/09
4315
PL5I9
4.95
PL802
5.05
P18021 3.50
P1820
2.95
PL5557 21.50
P032
0.60
P033
0.50
P081
0.70
PY82
0.70
PY83
0.70
PY88
0.66
P05004 1.95
P0800 P0601
0.79 0.79
063300 69.60 0E03-10 3.50
0E08-200
£145.00
0E40
65.00
OP25
1.00
00E0312
6.50
00E03-20
27.00
00902-6
16.50
00V03-10 Mu I.
lard
0.60
001/03-10 5.60
00V03-20A 18.50
00903-208 32.00
0OV06.40A
23.95
00V0 7-50 63.50
00203-20
42.50
00206-40A 45.25
0672/20 1.50 0S75/40 3.00
0092/10 8.00 0695/10 4.85
OS108/45 4.00
09150/15 0S150/30
05150/45
081200 0S1202 OS1203
001205 OS1206
0S1206
OS1207
051208
6.95 1.15
7.00
3.95 3.95 4.15
3.95 3.95
1.05
0.90
0.90
0S1209 001210
001211
2.00 1.50
1.50
0S1212 3.20
001213 5.00
0S1215 2.10
001218 5.00
0037
9.50
0037
11.50
0903-12 4.95
01/05-25 1.75
01/06-20 29.50
092-250C
46.00
0908-100
145.00
003.125 49.50
004-250 65.00
004-400 71.95
RIO
4.00
616
12.00
017
1.30
018
2.50
019
2.50
620
1.20
01169 55.00
RG1.125 4.05
061 - 240A
14.50
RG3.250A 3.50
063-12504
35.00
RK2K25 82.80
IRK- 20A 12.00
0116
1.50
RPL16 RP013 FIPY43
12.00 2.50 2-60
RP082
2.50
R63-250 15.00
003.1250
38.00
056/3 46.00
RS885 RS688 56F17 S6F33
SI1E12
630/2K
S1134/1K
0109/IK
S130
54.06 52.15
5.15 29.68
341.00
12.00
10.00
16.00
5.116
SI30/P 8.95
SC1/803 8.00 SC1/1100 SOO SCl/1200 5.00
SCl/1XX) 4.00 SC 1/2800 5.00
608000M
44.00
SP1B
4.14
SP41
6.00
SssP54o21
100 34.00
5111
1.60
ST9280/40 11.68
STV263/90
SU42
15.58 4.118
162 5/300
U.00 TB2-300 46.00
763/2000
364.00 1131-2-300
278.00 TD1.100A
26.00 T003-100
TD3-12 TP25
38.00 4.00
1.50
TTiSlPl4
11 15 1121
7.00 1.50
34.118
45.00
7722
46.00
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54.00 TY2-1254
TY4-400 8m6o.0o0
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3114.00 TYS2/250
376.00
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2.75
11.95 2.00
0.90
0.90 9.00
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0.70
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1.20
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1.00
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2.50
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0.65
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1.75
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1.20
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1.15
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1.15
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0.80
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2.50
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3.50
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0.83
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3.50
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8.00
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9.00
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3.50
UY85
0.70
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250.00
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225.00
V241C/1K
195.00
92464/2K
315.00
V339
3.50
VLS63I 10.95
VP133
2.00
0075/30 3.00
VR101
2.00
VR105/30 1.50
90150/30 1.15
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2.50
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4.50
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1.30
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5.00
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1.00
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1.50
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001-1600A
49.50
001-3200A
79.50
501-64004
99.50
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6.95
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23.00
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12.00
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YJI060 265.00
01 1020 29.00
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277
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23030
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9.00 15.00
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4.00
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8.00
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2749
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241000 12.50
241001 1.60
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2C1040 8.00
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2M10213 8.96
D11021 8.00
ZAA 1023 7.96
2M1041 14.00
2M1082 9.00
ZA11084 10.00
ZMI171 9.00
M1202 115.00
21.41263 4.00
2641612 3.00
143
4.50
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1.20
18361
1.95
1822
10.00
1824
14.95
1835A 29.50
10C2A 2.50
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2.50
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2.50
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2.50
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2.50
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25.00
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0.55
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0.70
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2C40
37.00
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2C42
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32.00
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1.50
2B7
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0.95
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93.00
21(25
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95.00
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34/10713 12.00
34,098 11.00
34/1108 12.00 36 141K 11.50
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342
3.95
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3.35
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3626
24.00
3628
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3C45
24.00
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4832
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46074
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4026
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2.116
4.152
75.00
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54/1020 9.60
54152M 9.00
54163K 10.00
5417016 4.25
SA- 206K 10.00
54-180M 9.00
44M8
4.15
54M8
2.15
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1.20
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56.254M 14.60
58-255M 19.50
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58/25641 9.00
58-257M 9.00
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56468
3.80
511460
3.60
514
5.06
51146
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1.94
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647
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1.50 1.95 150 2.00 2.00 1.00 2.00 0.60 3.25
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1.95
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3.95
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8.95
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2.95
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2.50
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2.30 2.30
1.75
2.543
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1.75 2.95 4.50 1.30
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6032
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2.50
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9.50
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1.98
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4.95
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3.15
5.15
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2.95
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3.95
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0.60
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4.50
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2.50
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1.20
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1.30
6067
1.35
6087
1.33
68/761 1.35
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1.33
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1.35
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1.95
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1.75
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1.15
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0.65
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1.00
604
1.50
60561
1.00
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2.25
746
4.50
747
2.00
7407
1.75
74U7
1.50
767
2.50
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2.50
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2.50
7,17
5.50
797
4.15
704
2.50
8E110
2.50
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1.95
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2.30 1.93
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1.30
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0.75
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1.95
101:114
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10P18
0.70
101011 1.00
101012 0.65
11E3 1246
85.00 3.95
12406
1.50
12468
1.50
12415
1.00
12416
0.95
12477
1.13
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1241.16 124U7
1.30 0.33
12496
0.80
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124%7
0.65
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12AY 7 3.95
124274 1.95
I21344
12646
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3.50
1.50
1.95 2.50
12616
1.75
12BY7A 12076
2.75 4.9
12CA5 12C06 120066 120W44
1.96 1.20 3.50 3.150
I2DW7 2.50
12E1
17.96
12E14 24.00
126147 4.50
1214674 4.50
12/761
121(5 12K761
3.50
1.00 0.60
1208
1.10
12SA7GT 12067 12SH7
12007
125/7 1258761
1200761 1303
1307 1307
1.00 4.75 1.00
1.00
0.60 1.85
1.50 3.20
3.20 2.50
1309 130187
13E617
1407 17EW8
3.20 2.95
3.30
1.00 0.96
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2.50 2.75
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1963
17.00
1984
23.05
1985
33.50
1906 2042 3001 201 F6 2011 2001
2003
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0.70 3.50 0.96 0.85
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20P4 25P5
211U8
2481
251661
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29C1
30C17
30C18 3005
30FL1 30012 300112 30FL13 3001_14
301.1
30115 30117 30P4M18
1.95 1.15
2.50
39.50
1.76
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19.50
0.40
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1.00 1.35 0.95 1.10 1.26
0.45
0.60 0.80 1.00
301,12 30018 30P19 30PLI
1.00 0.60 1.00 2.50
30P113 0.60
30P114 1.75
31J064 3.30
334 158M
19.50
3545
4.50
351801 2.00
35W4
0.70
3523
1.85
:SHE 7 4.50
40KD6
5.30
42
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47
8.00
5045 5005
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19.50 12.50
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5728 7054
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7064 7154
8.00 6.00
715C
45.00
7256 803
273.00 14.95
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39.00
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1.60
-1
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810
45.00
811A
12.95
813
18.50
813 USA 45.00
8298
14.50
8324
14.50
8336
60.00
6664
4.50
872A
23.00
873
50.00
884
3.30
927
15.00
930
9.95
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13.95
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1.00
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1.00
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0.60
1619
2.30
1625
3.00
1626
3.00
1927
25.00
2050
3.93
2050W
4.50
3545
4.00
4313C
4.00
43280
9.00
5642
9.30
5651
2.30
5654
1.93
5663
1.95
5670
3.23
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4.50
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4.30
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3.30
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2.73
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3.30
5718
6.15
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2.30
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1.50
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1.93
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2.50
5750
1.85
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2.95
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4.95
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5840
3.50
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11.00
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13.95
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2.00
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2.95
6067
1.95
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4.20
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6096
2.85
6132
10.00
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2.30
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6.45
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2.30
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2.23
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2.00
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5.50
6870
11.50
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9.50
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4.50
7167
3.95
71894
2.95
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5.50
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18.50
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3.95
8417
5.95
18042
10.00
'8045
10.00
MARCH 1985
please mention AMATEUR RADIO when replying to any advertisement
53
QUESTIONS & ANSWERS
RAE PRACTICE DEVISED BY R.E.G. PETRI G8CCJ
1. The PN junction shown in Figure lis: (a) forward biased (b) reverse biased (c) back biased (d) non- conducting
Fig 1
Fig 2
>70 6
OIL
9. Which one of the following waveforms would be observed as an oscilloscope connected across the load resistor RL (Figure 6)?
2. When the wiper of the potentiometer shown in Figure 2 reaches the positive end at B the: (a) deflection layer will be at its widest (b) deflection layer will oscillate (c) diode will conduct (d) battery will be short-circuited
3. Figure 3shows aforward biased silicon diode. What potential
difference would you expect to measure between the anode
and cathode ( X)?
(a) 0.25V
(b) 0.40V (c) 0.70V
Fig 3
A
(d) 0.95V
4. If the diode shown in Figure 3 is substituted for a forward biased germanium diode what will be the expected potential difference across the diode ( X)? (a) 0.25V (b) 0.40V (c) 0.70V (d) 0.95V
Fig 4
5. Figure 4shows a semiconductor device. Which one of the following symbols is most likely to represent it?
'11) '1E0a
6. The symbol chosen for your answer to question 5is that of a: (a) dual- gate MosFET (b) triac (c) field-effect transistor (d) NPN transistor
Fig 7
I
10. Figure 7shows the circuit of atypical: (a) common- emitter amplifier (b) common- base amplifier (c) common- collector amplifier (d) common- drain amplifier
11. Referring to Figure 7, for good dc stability, the bleed current flowing in the potential divider R1 and R2 should be: (a) at least equal to the base current (b) about one tenth of the base current (c) twice the supply current Is (d) about ten times the base current IB
12. Referring to Figure 7, the capacitor 03 should have a low reactance at the operating frequencies to: (a) produce negative feedback (b) prevent negative feedback and subsequent reduction in gain (c) prevent oscillation (d) change the sign of the input waveform
13. The current flowing in the emitter resistor R3, Figure 7, is: (a) equal to the base current 16 (b) the sum of the base current and the collector current IB + IC (c) the collector current minus the base current Ic-IB (d) the supply current plus the collector current Is + lc
7. The maximum reverse voltage that a diode can withstand before breakdown is known as the: (a) maximum load voltage VL (b) peak load voltage VPK (c) maximum back EMF VbEmF (d) peak inverse voltage P, v
8. Figure 5shows the circuit symbol of a:
(a) charger rectifier
(b) charger diode
(c) Zener diode
Fig 5
(d) light- emitting diode
14. For the common- emitter circuit it may be said that the: (a) emitter is common to both the input and the output (b) circuit is rather common and should be avoided (c) emitter supplies the power for the amplifier (d) collector supplies the power for the amplifier
15. Typical values of input/output impedance for the common emitter amplifier could be about: (a) 10- 50W10- 50e (b) 50- 500e/100- 500S/ (c) 1-5K,W5-30K11 (d) 1-5MW5-50M.e
54
please mention AMATEUR RADIO when replying to any advertisement
MARCH 1985
QUESTIONS & ANSWERS
Fig
Fig 10
16. Figure 8 shows a common- emitter tuned amplifier. The selectivity is determined by the: (a) ratio R1/R2 (b) current gain of the transistor (c) supply voltage Vc (d) tuned circuit
collector
Fig 9
22. Figure 10 shows the circuit of atypical: (a) common- emitter RF amplifier (b) common- base RF amplifier (c) common- collector power amplifier (d) low- noise dc amplifier
Fig 11
17. Figure 9 shows the circuit of a two stage RC coupled amplifier. One of the factors which limit the high frequency response is: (a) stray capacitance which shunts the signal (b) the amount of ripple on the supply voltage (c) solar activity (d) orientation of the amplifier relative to the Earth's magnetic field
18. Referring to Figure 9, what is the purpose of capacitor C2? (a) to improve low frequency response (b) to set the bias voltage for Tri (c) to couple the signal from Tri to Tr2 without blocking the dc conditions (d) to prevent oscillation due to the high voltage gain of the two stages
19. What is the configuration of the circuits shown below? (a) common- emitter (b) common- base (c) common- collector (d) split stator
23. What is the circuit configuration of the amplifier shown in Figure 11? (a) common- emitter (b) common- collector (c) common- drain (d) insulated base
24. What is the voltage gain of the amplifier shown in Figure 11? (a) less than unity, < 1 (b) greater than unity, > 1 (c) unity (d) greater than 100
25. The common- collector amplifier ( emitter follower) is useful: (a) when high voltage gains are required (b) when negative power gains are required (c) for matching low voltage batteries to high voltage circuits (d) for matching high to low impedances
Rg 12
20. The current gain of the common- base amplifier is: (a) less than unity, < 1 (b) greater than unity, > 1 (c) unity (d) 10-100 amps
26. What is the circuit shown in Figure 12? (a) common- collector RF amplifier (b) common- base RF amplifier (c) common- emitter tuned collector oscillator (d) common- base tuned emitter oscillator
21. What values of input/output impedance would be fairly typical of acommon- base amplifier? (a) 10-200f2/100M1-1M1/ (b) 1-5Ki1/5-30Ki2 (c) 1- 5M12/5- 30M11 (d) 10-20K11/5-30Mt1
27. The frequency of the oscillator shown in Figure 12 is determined by components: (a) R1 and R2 (b) R3 and C3 (c) L2 and 02 (d) Li and Cl
MARCH 1985
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55
QUESTIONS & ANSWERS
Fig 15
ISO .
300 *
lee
no .
e
1.0 . OW 360'
28. Arrange the waveforms shown above to represent the phase
relationship of the input and output signals of common-
emitter, common- base and common- collector amplifiers
respectively.
(a) a, b, b ( b) a, a, b ( c) c, b, a ( d) a, b, c
34. The circuit shown in Figure 15 is that of atypical dual- gate MosFET: (a) attenuation circuit (b) power amplifier stage (c) mixer, or frequency changer stage (d) voltage controlled oscillator
29. Figure 13 shows the typical circuit and collector current waveform of a: (a) class A AF amplifier (b) class B AF amplifier (c) class A RF amplifier (d) class C RF amplifier
30. A common application for the circuit shown in Figure 13 is: (a) high power audio amplification (b) general purpose audio amplification (c) medium power rectification (d) RF power amplification
Fig 14
01.1.11
35. The advantages of using adual- gate MosFET in the circuit of Figure 15 include: (a) heavy loading of both the input signals and the power supply (b) low impedance at 91 and variable impedance at g2 (c) low conversion gain and high intermodulation (d) high input impedances at gl and g2 and high conversion gain
This is the second part of a
series of multiple choice
questions and answers which
Ihave prepared to follow Bill
Mantovani's series Back to
Basics.
The
questions
will
hopefully provide the stimu-
lus and guidance for more in-
depth reading of this part of
the syllabus.
Attempt to understand
some of the basic physics,
especially the PN junction
diode, remembering in which direction it is forward and back biased. This is a favourite question and is of
course important to know when experimenting in the shack.
Practice circuit recognition from diagrams in the magazines, and remember that
your RAE lecturer cannot cover every possible circuit arrangement that you might encounter.
Now let's plug the book...
31. The circuit shown in Figure 14 uses afield-effect transistor (FET). What is the circuit? (a) a high stability mixer stage (b) a crystal controlled IF amplifier (c) a crystal controlled oscillator (d) a microphone amplifier
32. The three connections or lead- outs of the junction FET shown in Figure 14 are: (a) drain, grid, screen (b) diode, silicon, getter (c) source, drain, gate (d) screen, grid, detect
33. Fine tuning of the output frequency of the circuit shown in Figure 14 is achieved in practice by: (a) placing avariable capacitor of suitable value across the crystal (b) slowly swapping the positions of Li & Cl (c) replacing R2 with a 10-60pF variable capacitor (d) adjusting the battery voltage
For more question and answer practice Ray Petri's book The Radio Amateurs' Q & A reference manual' is available from:
W P Publications, 11 Wayville Road, Dartford, Kent DA1 1RL. Price £ 5.95 & £ 1.00 P&P The book contains 20 sections of multiple choice questions and answers which follows the RAE syllabus in roughly the same order than any recognised RAE course would progress, making it an ideal source of course homework. The book is also available from your local emporium.
Now turn the magazine upside down and see how many you got right!
ANSWERS
*P -- 9£ : 0 -- 17£ : e -- ££ : o 3£ : 0-- 1.£:P -- 0£
:P -- 63 : e -- 83 : P-- L3 : 0 -- 93 : P -- 93 : e-- 173 : q -- £Z : q -- 33 : e -- LZ
:e --ce
0-81,
o--çL
--LL e--01, : 0 -- 6 0--.8:p--Z:p--g : e-- L
56
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· RECEIVER SPECIAL
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DON'T MISS THE APRIL ISSUE
On sale 28 March
SECONDHAND EQUIPMENT GUIDE
The day after I posted last month's copy to the printers I received two letters, both detailing good examples of the common faults Ihad just described. The first was from G8GI and refers to a common fault on the TS530S, whereby the aerial changeover relay case distorts as it gets warm. This eventually prevents the relay contacts moving properly, leading to the PA running into no load and resulting in PA failure. Thanks for the tip.
The second letter was from G3JKV, who details acommon fault on the IC720: poor receive sensitivity after band changing due to no dc flowing through the switch contacts. As G3JKV rightly points out, a momentary touch of the transmit switch will restore performance, but there is amod to cure the fault. G3JKV admits to being lazy, and hasn't bothered to modify his rig. He has however repaired dry joints in an 102, an IC251 and an 10255.1 find this interesting
because Icorn gear is not noted for poor workmanship and Ionly occasionally find dry joints. The most usual failure of any Icorn gear I repair is purely random component failure. Ithus welcome your letters since my faults are obviously different to other peoples' and Iam only too pleased to pass on faults other people have come across.
Dressler D200S These 2m linear amplifiers have been
around for about three years now and seem to be eating PA valves at horrendous rates. There are several causes of valve failure, so Isuggest that you check out the following possible weaknesses before you fit a replacement.
Some variants of the rig have aheater transformer with the correct output voltage stamped on it ( 5.9V) but, unfortunately, the wrong input ( 220V rather than 240V). Eimac recommend a 5.9V heater voltage at the valve pins.
Some informed sources say that a3% increase in heater voltage will half the valves' life, so that 5.9V is essential. There are two ways to drop the volts,
either with a 0.22 ohm resistor in the heater circuit or an 18 ohm resistor ( adjust to suit) in the transformer primary.
Believe it or not, the anode line is grounded by rivets. These rivets are subject to both physical heat and circulating RF currents and are often open circuit. The best solution Ihave found is to drill them out and fit nuts and
bolts, preferably with star washers. Another failure on these amplifiers
concerns the antenna load variable capacitor. Although this is provided with an earthing tag, the amplifier relies on
by Hugh
Allison G3XSE
the shaft of the capacitor to provide the earth. The shaft very often doesn't provide agood enough earth and this can lead to poor amplifier efficiency. It is fairly easy to solder an earthing strap onto the capacitor shaft and make agood job of it. Incidentally, this was the cure for an amplifier that was ' splattering' all over the band. Isuspect that the shaft was radiating within the case and causing RF instability. If you are offered a cheap example of this amplifier secondhand, Isuggest you check it out carefully. Proper Eimac valves are very expensive (£50±).
Audio output ICs I have had several letters recently
asking about integrated circuit audio amplifiers. Most people often suspect that they have died but are reluctant to buy and fit a replacement until they are sure. Firstly, check that there is a good earth to the IC. This should be fairly easy
Input
Input
coupling' capacitor h
Input pin
A typical audio output stage
to find. Next, check that there is asupply to the chip. Fairly straightforward so far. The trick now is to locate the output pin and check its dc level.
The diagram shows a simplified schematic of the typical audio output stage. Remember, there will probably be headphone and/or extension speaker sockets between the speaker and the printed circuit board. It's worth remembering that the changeover switches incorporated in the speaker and headphone sockets can often go open circuit-- the quickest way to check these out is to plug in an external speaker. However, Idigress.
The output pin should be at half rail, ie if the chip has ax12 volt supply, then the output pin should be at 6volts. If it isn't, then the IC is probably dead. Inormally unsolder the input pin ( or pins) first and re- check. It isn't unknown for the input coupling capacitor to go a short, thus upsetting the bias. This is particularly
Output ccaopupalciintgor "
Output pin; look for 1/2 supply here
58
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MARCH 1985
SECONDHAND
common on early ' Beltek' rigs for some
reason. Incidentally if you are interested in a
real bodge, and Iam ashamed to admit to doing this on a few clock radios, leave the meter connected to the output pin and try taking the input pin up to rail or earth via a4.7K resistor. If the meter now
shows adc level, adjust the resistor value to give half rail and feel embarrassed. The reason this works, sort of, is that the ICs are dc coupled. The output bias is often pre-set by circuitry within the chip and this can go wrong, even though the audio path is still OK. By setting the input
voltage you can control the output and
thus get it ' working' again. The distortion can be horrendous but it's amazing what some people will listen to!
Although not normally found in amateur equipment, the Texas SN76 series of audio amplifier chips can cause a lot of heartache. These are fitted in some Fidelity UA series hi-fi units. After following the above sequence and replacing the chip, turning the unit on produces a womph' from the speaker then nothing. Replacing the chip can get things working ( or the same might happen again). I've seen grown up service engineers cry whilst servicing equipment containing these chips. The
only plausible explanation I've come across is that the output coupling capacitor is of too high avalue. On initial switch on, the in- rush current through the top audio output transistor within the
chip is so great that the transistor goes open circuit.
I've seen recommendations to fit a22
ohm resistor in series with the bridge rectifier and the main smoothing capacitor to slow down the start up current. As I said, not normally an amateur radio problem, but once people find out that you ' know about radios' you end up repairing all sorts of rubbish, so I've passed on the tip.
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FOR SALE
· Trio TR7800 and PS10 PSU with memory back up supply £ 150. Belcom LS2OXE 2m hand held. £ 75. MFJ-901 versa tuner, tunes coax, wire and balanced lines, ( 1:4 balun built in), imported from USA, new unused £50. Cordless telephone new unused 120V only hence £25. GM4DHJ. Tel: ( 041) 889 9010. · lcom 251E all mode two metre transceiver inc
service manual. Baby forces sale £350 mint, no offers please. R Oakes, 3Rumbold St, Abbey Hey,
Gorton, Manchester 18 7LU Tel ( 061) 231 4854. · Eddystone 840C 500 to 30MHz 5 bands in FB cond'x Rx. Buyer inspects and collects £85, or would consider xchange for any tele cine gear, camera, less lenses, and recorder. Projector not required. Cash adjustment. R W Jennings, 20 Newhouse Close, Thanington Without, Canterbury, Kent. Tel: Canterbury 65200. · Yaesu FRV7700, VHF converter, new unused
£50.00. A Clark, 37 Burmarsh Road, Hythe, Kent CT21 60L. Tel: ( Hythe Kent) 68132. · Yaesu FRG7700 and FRT7700 ATU mint condition £220 or exchange Ham Int Jumbo or auto scan CB 40 chan, cash adjustment either way. David Harvey, 93 Lochend Road, Gartcosh, Nr Glasgow. Tel: Glen Boig 872656. · KW 202 Rx £ 120. KW viceroy mark 3A Tx. OK SSB needs attention on CW £35. Heathkit RF signal gen
£20. Advance audio signal gen £25. Short wave mag with index - Nov 1964 to April 1979 £ 15. Practical Wireless Sept 1982 to Feb 1984 £3. Ham Radio Today June 1983 to Oct 1984 ( less two issues) £4. Buyer to collect. Not on phone. G3WXT, 36 Hart Road, Byfleet, Surrey KT14 7NH. III ' corn IC290D all mode 25W 2m Tx less than one year old. Fitted with G3WPO preamp £300 or will exchange for FT10IZD with or without ATU or any comparable Tx with digital readout. Sale includes all accessories inc PSU rotator and 12 ele zL special. W Smith, 41 Rockleigh Ave, Aberbargoed, Mid Glam CF8 9BQ. Tel ( 0443) 820617 after 6pm. · Amateur radio enthusiasts, old Bird electric organ full of spares £50 ono. Mains transformer only faulty. If interested Tel: Warwick 498770. · Crystal calibrator by GEC old, six valves. 100KHz 1000KHz 5000KHz input, output, phones, also variable oscillator tuning scale 13 x9x7in £5. Mobile whip ( G3FIF) long telescopic, 160m coil, base, £ 10. 80m coil £8. Mains transformer, output
4.5V 5-10A £4. ' Belling- Lee' set lead interference filter 2A £4..5mFd condenser 2500 VDC working £2. *Gilson' output transformer HT, A, S twice out 15n, 3.7(j, £3. Edwards, 244 Ballards Lane, London N12
OEP. Tel: 01 445 4321. · FT707 brand new three months old, never been used as aTx only Rx, have lost all interest in radio sell for £400 ovno. Also Ihave aJEN SX1000 mono synth ideal for abeginner cost over £350 new, just 18 months old, sell for £85.00. Please Tel: ( 0283) 33526 after 6pm. · Yaesu FR101 with matching speaker VHF 2
metres and 6 metres in excellent condition £250. Kenwood headphones HS5 new £ 19.00, ideal for SWL. Many text books for homestudy course for RAE. Tel: 01 253 6725. III Standard C78 430MHz transceiver + UHF FM 10 watt booster + mobile bracket, all boxed, 2months old, may P/x on cordless phone or sell cash complete outfit cost £320, for quick sale £200. Jim Shepherd, 6 Bergen Walk, Corby, Northants. Tel: Great Oakley 743807. · SEM Z match ATU 10m to 80m new Aug 1984 £ 55. Ezitune noise bridge new July 1984 £25. Packing and carriage included. Tel: G5CDE Egham 33500. · RC11 infra red remote controller for loom R71 receiver, £32. Global AT 1000 antenna tuning unit £30. Both mint condition boxed still under guarantee. Tel: 01 570 5603. · Datong morse keyboard. as new, four indepen
dent memories plus keyboard memory. Speeds 5 to 130 wpm, many special features and a joy to operate. Having sold rig must now sell ancilliaries. Also CP5 five band vertical antenna wih five tuned radials, a super DX antenna. Keyboard £80 and antenna £ 50. Two bargains. Tel: Sapcote 2955. · Exchange or sell Racal 17L ( 17T) complete with instructions and a Perbrowns type F headphone, good condition £250, or exchange for FRG7700 with ATU etc, also for sale Redefon International
unit VHF FM radio telephone type 11, no mike, but with spare chassis £50 ono. T Hoyle, 35 Marton Grove, Inglemire Lane, Hull, Humberside HU6 8NZ. Tel: 801771. · Burndept BE471 UHF H held six channel Xtalled RBO, SU8, RB14, only. Complete with stand, charger, 2 sets, good nicads. Also new mobile mount for same. Absolutely mint cond. Also Pye T460 UHF base station Xtalled RBO very nice cond poss swap both for FT290 with cash adjustment or sell 13E471 with accessories £ 165 + T460 £85. Mr PA Soden, G8WAL. Tel: Albrighton 2393 ext 563 office hours only. · 10m, 15m, 20m, 40m, 80m, 160m reception over CW, AM, USB, LSB, slot filter BFO pitch AF gain peak RF, IF and RF gain. In brand new condition includes manual swap for FRC7 with VHF or Racal RA17, must be in good condition, or sell for £ 130. Prefer to swap consider FRC7 and 10m rig power supply twig mike or FRC7 and homebase GB. 27 Dodge Holme Gardens, Wheatley, Halifax, West Yorks. Tel: ( 0422) 240201 evenings. FT726R two and seventy fitted. Boxes and all handbooks. Divorce forces sale £ 750. Tel Wolverhampton 763387. · New brain computer with disc controller, 800K + 800K disc drive, and 3 megabite software. Runs CPM software ie word star and most languages. Original cost £2000. Also book single disc drive. Would exchange TS780 with cash adjustment. G6UDM OTHr. Tel ( 0902) 783338. · Yaesu F5OB amateur band receiver 10 to 80 metres for sale £ 75 or exchange for good 9.5mm projector or super 8mm projector and camera. Robins G8BSK, 290 Priory Road, St Denys, Southampton SO2 1LS. · The worlds smallest TV Sinclair pocket TV with Sinclair mains PSU under warranty, £70ono. What about a1923 Columbia Grafonola on oak pedestal. Tins, needles 73s etc. Sounds nostalgic to those over 60, offers. Fifteen complete vols of RSGB Rad Com free to anyone if collected. Tel ( 0582) 25519. · Revtec 934MHz CB transceiver, complete with
Cobra power mike and 5amp PU, recently serviced by Revtec and fitted with new frequencies. £200 ono. 19 Palamos Road, Leyton, London £ 10 7JF. Tel: 01 254 6621. · Yaesu FRG7700 receiver as new, digital clock and timer, handbook, £250. G3HRO QTHr. Tel: 01 460 7660. · Ham International Jumbo very good condition classic base station trans must go so sensible offers around £ 175. Also ZX81 48K plus data recorder and Alphacom printer, again sensible offers or will swap either/both for any HF trans old or new cash either way. Might consider 2 metre SSB stuff, antennae, transverts, even parabolics or WHY. Will travel anywhere for the right gear. Tel: (0244) 383180 anytime. · Gresham p/s GX30/10/13 10amp 30V £25. SX27
'1F Rx 27-143MHz works OK but really needs a e- amp £20. Heathkit SB102 Tx/Rx 10-80 amateur bands immaculate condx, inc p/pack, spkr, mike and junker key £210. AVO CT38 240V multimeter £10. Very rare Howard 450Rx, c1937, xtal filter etc, a collectors Rx. £90. US signal corp freq meter BC906D, needs VT172 tube + 45V £ 10. Hy- gain 18AVTNVB vertical £35. Hokushin HF5R ground plane for above £20. Exchanges for Fix on above gear. Wanted Racal RA63 or RA98 SSB adaptor.
Tel: ( 0908) 314095. al Antenna change over relay, heavy £5. Oscar SMC 2metre 7/amobi le whip with gutter mount £ 10. Jaybeam 8 el 2 mir beam £5. 4el and 3 el 2 mtre beams with alloy poles £5 each. Heath valve volt meter £ 10. Res/cap bridge £ 7.50. BC221 wavemeter £10. English equivalent £ 10. SWR meters £ 10. High quality CB set with K40 mag mount £30. All G3RCO. Tel: Seaton 21016. · Yaesu FT227 RB mobile 2M rig, six memories
scanning from mic, excellent cond, with bracket £135. Also Pye PFI pocket phones Rx/Tx unmodded £ 15 the pair. Tel: ( Hull) 802706. MI Chinon CE4 auto manual 35mm camera, 50mm, 28mm and 135mm lenses, case, flash gun, cokin and screw in filters case mint condition £ 120. Also Practica TL1000 35mm camera and case, 50mm lense new £ 40. Pye pocket phones Tx Rx £ 10 ( not converted). Exchange lot for HF general coverage Fix or for HF gear WHY. Derek Wilkinson, 43 Turnshaws Road, Kirkburton, Huddersfield. Tel:
(0484) 607866. · FTDX401 HF transceiver, complete with CW filter and matching speaker, top band thru 10m. Spare set of valves included, £250 ono. Tel: ( 0533) 891960 after 5.30. 111 SS105S 5band HF rig, TL120 200 watt PEP linear, Tytan 8.5A PSK, Ham International 15A PSK, Reace RS106 SWR/Pwr/mod meter, cost £720 new, 12 months old for £580 ono. Bremi 10 amp PSU, new unused boxed £50. MMT144/18 transverter 12
months old £85. Ham International Concorde II multi- mode ex- CB now 28-29.799 £200. Alpha channel switch fitted, equipment sold due to
bereavement. Mr J D Bolton, 10 Bowness Road, Coniston Park Estate, Timberley, Cheshire. · Yaesu FT- 480R 2m transceiver, 8 months old, never been used, guaranteed for 12 months, £250 ono. A Cocking, 31 Dryden Crescent, Stafford ST17 9YH. II 9mm Specto projector, type B with wide angle lens. Pathe Prince camera with holder for zenascope lens and view finder wide angle screen, offers WHY or cash. Howland West audio stereo headphones CIS 550 £ 10. Microwave Modules RTTY to TV converter MM2000 £50. G3WPO 2M pre- amp 12V dc £5. 29MHz pre- amp Telford Communications £7. Dr A C Gee, 21 Romany Road, Oulton Broad, Lowestoft, Suffolk. HR32 3PJ. Tel: 0502 65726. · Yaesu FT902DM transceiver plus matching transverter FTV902, as new condition £685. Tel: ( 31)
54264 Great Bookham, Surrey. · FT101B just realigned. FC902 as new. Yaesu FF501 filter boxed new. Altai dip meter boxed new. HyGain 12 AVQ 3 band vertical boxed new. Icom 10mtr FM converted CB rig. Spare valves for 101. £440 or best offer. N Bleek, 35 George Ave, Easington, Co Durham. Tel: ( Easington) 272702. · TR2200G 2m FM transceiver 12 channels, 6with crystals complete with Nicads, charger and carrying case. Good condition £70 ono. Tel: ( 0344)
778155 ( near Camberley). Ill Lots of old service sheets and manuals for amateur radio, vintage wireless, test equipment, audio, TV video etc. Copies available. Large SAE with ' wants' and I'll try and help. Maurice Small, 8 Cherry Tree Road, Chinnor, Oxon OX9 40Y. · ZX81 computer + 32K rampack & books. Also a good selection of software including Morse reader & tutor, QRA and Maidenhead Locator logbook programs, £40 ono. David Crossley
G6ZXP, 15 Mylgrove, Roman Way, Coventry. Tel: (0203) 412861. · 48K Spectrum 2 months old, leads, manuals, PSU + £70 worth of software, and Currah speech unit £90. Collectors item R1155B immaculate, unmodified handbook for all models, PSU/test unit with pre- amp and speaker built in £65 ovno. Ferranti valve interstage transformer air ministry
60
please mention AMATEUR RADIO when replying to any advertisement
MARCH 1985
FREE CLASSIFIED ADS
variable voltage PSU 1-15V approx requires meter in TUSB case, offers invited, buyers collect or carriage extra. Borthwick, 92 Linglie Road, Selkirk,
PBorders Region, Scotland. · For sale American made bug key very good cond. £ 10.00. post paid. Also HE5 5band VERT ant, no radials, buyer collects. AE Sutton, 60 Birch Road, Hurstead, Rochdale. Lancs. Tel: ( 0706) 76848,
any time. II 32 band comm Rx digital, 0-30MHz USB/LSB, DR32-3100L batt/mains, Panasonic FIF3100, £ 110 + post. Tandy TRS80 model 4 64V twin disks with
printer DMP110 all four months old, inc 100 disks, disk storage, many books programs, paper, also CTR80A composer cassette, so you've got the best of both worlds. Ideal for home/trade. Total value £2900, sell for 1 /2 price ono. Consider WHY exchange with cash adjust. Buyer must collect. Tel: ( 0473) 85526 anytime. · FT29OR for sale nicads, charger, manual but no case. £200 VGC. Contact Les, G6LOK, evenings.
Tel: Rochdale 525490. · FL2100E3 Linear amp mint £275 ono. Heathkit HW8 incl PSU built March 1983, in mint condition
£125 ovno. GHFKZ. Tel: ( 061) 624 2808. · Yaesu FRG7 receiver excellent cond with manual £ 125. Buyer to collect or arrange carriage. WC Brock, 22 Fountain Head, Seaton Sluice, Tyne Wear NE26 4HU. Tel: (0632) 371994. · KW2000E in reasonable condition, some spare valves £200. Semi automatic bug key £ 15 ono.
Office dictating machines Grundig £5 ono.
Contact GW4NBY QTHr. Tel: ( 0656) 56576. · Kenwood R600 communications receiver. Cost £263 vgc with manual will sell for £ 190. Tel: ( 021) 783 0268. · Yaesu FRG7000 communication receiver mint condition, digital display, hardly used; original case instruction manual, gift £ 110. Dave G6KTI Tel:
urnham-on-Sea 788970. I Lowe SRX30 communications receiver. Hardly used £50 ono. Mr G Lander, 87 Hartfield Ave,
Elstree, Herts WD6 3JJ. Tel: 01 953 9780. · FRG7700 Rx, FRV7700/C converter 130-160MHz
FRT7700 ATU all mint cond boxed £350 ono. G6NWN not OTHr Tel: ( 0623) 512369. · FRG7700 £ 180, FRV770DA £40, Trio 9R59DS x- cal fitted speaker spare set valves £50. All mint cond, manuals original packing. Lafayette HE40 £20. Carr on above extra. Tel: Smyth ( 0436) 71181. · Yaesu sommer kampt 767 Dx ( 707). Good condition 26MHz 27MHz will convert back to
normal bands. All other bands HF as standard. Also Yaesu ATU £385. Tel: ( 0625) 617821. · Azden mic DX354 £ 18. Datong speech processor
ASP/A £40. 0 Multiplier R010 ( valve) £8.50. Akai stereo amp AM u1 £30. Philips VCR £20. SP102 Ext speaker £35. SWR bridge SMCT3-170L 3.5-170MHz £15. K G Atkins, 30 The Brow, Woodingdean,
Brighton, Sussex. Tel: ( 0273) 309127. · Spectrum 48K computer, currah speech unit + £70 worth of games as new exchange for
Eddystone ECIO MKII receiver, must have battery
container and handbook, and in good condition. R1155 receiver immaculate unmodified collectors item + PSU/test unit built in speaker and amplifier, new handbook exchange for Vega 402DE TV must be in good condition with handbook. Borthwick, Torwood, Lilliesleaf, Melrose, Borders Region. Tel: ( 08357) 314. II Simpson digital volt, ohm, milli ammeter, 1000V 600V to 200 milli volt, five ranges, 20m to 200ohm,
six ranges 10 amp ac-dc to 2milli amp five ranges. Nicad cells built in recharge facility mint condition, £80. Tel: ( 0532) 735543. · AR40 rotator one year old inc cable £45. Jaybeam 8ele quad 2metres complete £22. Buyer collects no offers at these prices. D Dicks, G4YJG. Tel: ( 0442) 40467 after 6pm. MI Hy-gain 12AVO 10-15-20 meter vertical. Brand new. Still in box cost £54 will take best offer. Norman Bleek, 35 George Ave, Easington Colliery, County Durham. Tel Easington 272702 evenings. · RCA AR88D receiver, 0.54 to 32MHz, immaculate, good performance, handbook. £60. Buyer collects. Bill G4YZE Tel: ( 0204) 41317.
· FT757GX station comprising of FT757GX HF transceiver FP757HD heavy duty PSU MH-1B8 mic FC902 ATU. Never used. Still in box with warranty,
£800 ono. 118 Wilsden Ave, Luton, Beds. Tel: ( 0582) 422810.
· Realistic DX300 receiver good condition with instruction manual 0.1-30MHz AM, SSB, CW, £ 100. J
Stancliffe, Plot 56, Smithfield Road, Alphington, Exeter EX2 8YD. Tel: Exeter 39990. · Liner 2piptone, power pack good condition £60. Mutek SLNA 144S pre- amp, ex- performer, suitable for liner 2 £20. G4XSM, Bury St Edmunds. Tel: ( 0284)
68084. · L5707 ( Belcom) 70cms multi mode SSB FM CW AM 10W, trans mic etc, near mint boxed £220 ono.
Yaesu FT48OR 2m multi mode 10W mobile vgc £260. FT101B HF trans valve PA ( Yaesu) £ 195. Tel: ( 0305) 786930. · Trio JR310 HF Rx 1.8 to 28 £70. ' corn IC215 Tx/Rx 15ch with all xtals, Nicads, £65. 2m Bel beam £5. Pye PF2 with 70cm xtals 3ch needs some attn £30. Wanted SSB unit for Grundig ' Satellit' 2000 Rx.
G8MPG. Tel: ( 0603) 810831. II Lafayette HA700 general coverage receiver, 150KHz - 30MHz. Good condition, £60 ono. Also, Aiwa AD3500 cassette deck, with Dolby B and C nr 3 head, soft touch control, Variable bias, good condition, £60 ono or Px for Yaesu FRG7 ( Digital read out model). Tel: Leeds 663814, after 1pm. al Yaesu FRT7700 aerial tuning unit as new with instructions £30. ACE SWR bridge with 0-5W power meter £5. Both plus postage. Tel ( 0795) 873100. · Trio 9R59DS Rx vgc boxed £ 45. Datong ANF CW notch filter mint £30. Drae 6amp 13.5 vdc PSU Vgc £30. FX1 ( Lowe) wave meter 1.6MHz to 250MHz £20
FT221R 2m multi mode trans 10W vgc £220 FT101ZD MKI IHF trans vgc £395. Trio TS130V HF trans CW filter 10W vgc £360. FT200 FP200 HF trans
valve PA £ 170. Tel: ( 0305) 786930. · Frequency counter £45, Eddystone 750 £ 75, Nato 2000 FM all frequencies. Tel: ( 0283) 221870. MI Drake MN2700 ATU. £200. 1C740 with FM, in-built
PSU, filters. £600. Lunar PAE432-5 pre- amp ( NF 0.9dB). £20. MML 144/100S 2m linear with pre- amp. £100. MMT 1296/144. £ 120. MMT 432/144 with repeater shifts. £ 120. MMT 432/28 with repeater shifts, £ 110. MMC 50/26 converter. £ 15. SSB Electronics 23cm GaAsFET pre- amp. £50. Write G3OSS, Angus McKenzie, 57 Fitzalan Road,
London N3 3PG. · MM2001 RTTY to TV converter. £ 140 ono. Or swap for SX200N or Bearcat scanner. Steven Rake, 80 Cripps Avenue, Tredegar, Gwent NP2 3PB. 111 Yaesu FRG7700M Rx, in excellent condition, only 7 months old. Together with Datong active antenna, 6months old. Original total cost £480, will accept £310 or nearest offer. Nigel Lloyd. Tel:
(0422) 884113 evenings. · Morse Tutor ' Drae'. Only 6 months old, still as
new. Single letters ( with repeat). Groups of 5 random letters. Continuous Morse. Built-in practice oscillator. Built-in mains power supply. ( Cost £52). Bargain at £35. Buyer inspects and collects,
Seaford, Sussex. Tel: ( 0323) 898515. II Trio JR -599 Custom Special X communications
receiver. SSB, FM, CW, AM, all solid state circuits. Crystal filters. 1.8 to 29.7MHz, amateur bands, also 50MHz and 144MHz converter, and WWV. Excellent
condition, ( can be used with a Tx599 for transceiver, receiver operation), complete with
service manual. Buyer inspects and collects. £ 150 ono. ( G1EMQ). Tel: ( 0323) 898515. · Yaesu FT7, good condition. £230 or nearest offer, or will exchange for high power valve two metre linear amp or 70cm multimode with cash
either way. Jim. Tel: Swansea ( 0792) 793464 after 6pm. · President Grant FM/AM USB/LSB 25.625MHz to
28.305MHz. £ 160. Tel: Worthing 505296. · Emigrating, must sell quick. Therefore, all going cheap bird thr/line plus six elements. £ 150 NRD505 Rx b/new. £800. FT290, FT790. £ 150 each. BBC b. £200. TRS80 model 4 printer DMP110 twin disks, many disks and books, also WP programs plus many other computer inventory for this system. Also B/N valued at £3,000, sell £ 1,300 ono. All items view, demo, post or collect. Also cash only please. Ring me, John, and haggle for quick
bargain. Tel ( 0473) 85526 day or night. II Two 40 channel FM CB rigs. £8 for both. Not working 40 channel FM mobile. £ 15. 2 metre scanning receiver. £25. Two metre transceiver base station. £ 75. Eagle communications Rx. £50. M De Wynter, 2 Woodside, Wimbledon, London SW19. No telephone number. · Lafayette. AM, FM, SSB. Any offers? Tel: ( 0283)
221870. · BBC complete ham program, including digital clock alarm, erasable notepad, logging with full editing and auto mode/band/date facility, full global search etc. 2m/70cm repeaters shown on map of UK input suffix or 0TH for full repeater details, 0TH locator input co-ordinates and 0TH
pinpointed on map of UK, full graphics and professional presentation, fully menu driven comp
instructions. This program has been designed to give the op everything at his fingertips on disc £7. Also electronic keyer himoun EK103Z new. £35. Curtis KB4900 ASLI baudot CW keyboard and electronic keyer, see OST for spec, new, bargain. £120. HK808 Morse key new. £25. All plus postage. Tel: John G4TEN. ( 0258) 53075 weekends. · Microwave 24GHz; directional coupler and
detector with crystal. £28. Slotted line SWR meter (£700 new). £ 190. Variable attenuator. £ 35, also
bends, twists etc. Microwave 10GHz: 75mW klystron micrometer tuned with WG mount. £ 18.
25mW klystron. £ 4. Professional micrometer wavemeter. £ 78. Variable attenuator and detector
with crystal. £48. 1-2GHz wavemeter. £ 18. Veroboard 0.1 in brand new, 11 x3.75ms, 5sheets for £5.
Mann. Tel: Cambridge ( 0223) 860150. II Panasonic 3100 100-30MHz receiver plus FM broadcasts bands and SSB. Modified by owner for
use with loop ant. List price new £219. One year old, in first class condition. Sell for £ 115 ono, plus postage. Mr Ron Hall, 23 White House Court, Ushaw Moor, County Durham DH7 7NH. No
telephone number. II Marconi Marine multi standard TV receiver. UHF, VHF, 525, 625, line system NTSC. SECAM and PAL system. 4.5MHz, 5.5MHz, 6MHz, 6.5MHz sound. Complete with full service manual and operating instructions. Ideal for DX TV or ATV, at only £ 135 ono. Dave. Tel: ( 0202) 745136 or ( 0202) 730207. · Datong RF speech processor, model ASP. £60.
Datong up-converter. model UC/1. Converts HF up
to 144MHz, also 28MHz. Listen to HF on 2m rig or 10m rig with 29-1MHz bands. £ 75. Now have HF rig. FDK multi 750E 2mtr multimode. RF, SSB, FM, CW,
good condition. £250 or exchange for FT221 2 mtr multimode with cash adjustment. Len G6ZSG, Birmingham. Tel ( 021 453) 9762 anytime. · Yaesu FT980 boxed, as new. £400 below normal price, £930 only no offers. Cobra 148 GTL DX 10m transceiver, very good condition, boxed. £ 115 ono.
Microwave Module 28MHz to 144MHz transverter, boxed, as new. £65 ono. G4V10 QTHr, Tel: Bishop
Auckland ( 0388) 763501. · National Panasonic computer- controlled communications receiver, continuous synthesised manual/auto scan tuning. LW/MW/SW/FM, programmable frequency/clock/timer/calendar func-
tion, 11/ 2 years old. Immaculate. Any demonstration by appointment. Cost £2,250, asking £950 ono for this extraordinary machine. Tel: ( 0293) 32003. IN Realistic DX 100L gen coy Rx. £35. Also
Audioline FM CB rig. £ 15. Buyer collects or arranges carriage. Tel: Tony. ( 0925) 601041.
· Trio TR2500 hand-held, as new. £ 190. ST2 base charger, also as new. £40. Both surplus to requirements, will not split, buyer collects. Cash only, no cheques. Jaybeam 48 element 70cm. £20.
Tel: 01-540 3959. · Trio TS700 2metre multimode, plus VOX3, mike, also fitted, pre- amplifier to improve front end plus R2 R4 R5 R6 R7 fix channels. £310. Yaesu FT707 HF SSB transceiver, FC707 ATU, FU707DM VFO, FP707 PSU, YM35, mobile mounting bracket. CW filter
fitted, still under guarantee, 6months old. Used for SWL. £710. Both in excellent condition. Buyer
collects. David G11DS, Bungalow, Hollinhall, Hardcastle Crags, Hebden Bridge, Yorkshire. Tel:
Hebden Bridge 842243. la Microwave Modules 2m 23cms transverter ( new model). £ 185 ono. Tonna 23cms Yagis. £23 each. Stacking frame ( 4 Yagis). £ 15. NEC very high
resolution mono chrome video monitor ( as new). £75. 23/24cms filter ( per VHF/UHF manual) beautifully built. £28. Paul G4XHF. Tel: ( 0293)
515201. · Yaesu F5OB 80-10m amateur band receiver, best offer, or exchange for super 8mm projector and
camera, or 9.5mm projector, Pathe 200B 4-, VOX, etc. Will consider reflector telescope. PG Robins, 290 Priory Road, St Denys, Southampton SO2 1LS. · SX400 with power supply, less than 4 months
MARCH 1985
please mention AMATEUR RADIO when replying to any advertisement
61
FREE CLASSIFIED ADS
old, cost £630, offers of £ 550 or nearest offer. Tel: John. 01-688 8502, after 6pm weekdays and anytime
weekends. II Linear amp 2 metre band KLM electronics 160 watts, 13.5V dc, new unused. £ 100. Datong Morse keyboard model MK. £75. G E Goodfellow, 'Springbok', Poulders Road, Sandwich, Kent CT13 OBB. Tel: ( 0304) 612420. · Eddystone 730/4 valve receiver 540KHz to 30MHz in five bands. AM/SSB/CW. Has slight stability fault, otherwise in good condition. £50. Drake SPR-4 solid state receiver AM/SSB/CW full
coverage of medium and short wave bands. Can be fitted with accessory crystals to cover amateur bands. ( 80m fitted) in excellent condition, with manual. £ 120. Buyer to collect please. Mr R Wooden, 50 Langley Road, Staines, Middlesex TW18 2EH. · Microwave Modules 2m 100W linear MML 144/100-S 10W in 100W out. As new. £ 120 ono. Dave Sweetland, 48 Upland Road, Billericay, Essex. Tel:
(02774) 58489. · Large package of CB equipment, including 5 radios ( working), mobile and base antennas, power pack, pre- amp, SWR power meters, matcher, various mikes, 50-60 CB magazines etc. £220 complete. No offers. SAE for complete list. Mrs S A Kirkwood, 1Netherview, Wennington, Nr Lancaster LA2 8NP. II Have SX200N scanner 26 to 520, VHF, UHF. Also TV DX antiference aerial MH473 VHF covers 1to 3 bands, also Realistic PRO47 scanner, with 10 ham, 10 maritime crystals, fitted. Would sell or split. Offers. Tel: ( 051 922) 9632 evenings. · JR310 radio amateur receiver. £90 and SWL lar omni match antenna tuning unit, does not work with Trio. 1 Kenwood R2000 communications receiver. £29.75. Tel: Clochen 378. · American RTTY rev terminal unit type CV-89AURA-8A. £35. Also American T- M corpn digital readout VFO. Gives 3watts into 50 ohms between 2 and 8MHz. £35. Buyer collects. Nev Kirk, 54 Allendale Road, Rotherham, Yorks S65 3BY. · Sharp MZBOB computer 72K RAM, 40/80 character display, typewriter style keyboard and numeric pad, monitor and cassette deck built in. Basic, assembler, books, software. £395 ono. Or swap for amateur radio gear. Tel: Abingdon 27703. · Multi 700EX variable power etc, mint condition and slightly damaged Ringo Ranger. Will swap for FRG7700. Tel: Ireland 905768 after 7pm. · Hallicrafters HT37 Tx. £ 125. Hallicrafters SR400 Tx/Rx 400W. £200. Collins 32V3 Tx. £250. Collins 75A4 Rx. £375. G3GBB. Tel: ( 0284) 66496 evenings and weekends. · Icom IC255E 2m FM 25W transceiver, scanning mic, mobile mount, boxed. £ 125. Tel: Earls Colne (07875) 3442. · AOR2001 scanning receiver, complete as new. Very little use, 5 months old. £290. G Joseph, 15 Eden Close, Wembley, Middlesex. Tel: 01-997 0837. · Yeasu FRG7700M general coverage receiver, twelve months old, very little used. Also FRT7700 ATU and CWR 610E, CW RTTY and ASCII decoder,
all with manuals and original packing. All in excellent condition. £450 or nearest offer. Philip Cole, 20 Paultow Road, Bedminster, Bristol. Tel: (0272) 632400. · Eddystone EA12 HF receiver, covers 1.8 to 30MHz, excellent condition, handsome receiver. £140 ono. Or swap for Racal RA17 around same value, or swap for FRG7 and 10m FM rig twig PSU or AR88 and 10m FM rig twig PSU, or FR101 HF receiver fitted with 6m and 2m, or Lowe SRX 30 prefer RA17 or FRG7 plus FM 10m rig. Please reply asap, going in for RAE. D Haigh, 27 Dodge Holme
Gardens, Mixenden, Halifax, West Yorks. Tel: (0422) 240201 daytime only. II 18 volt power supply input 240V ac output 18V dc 1.1 amp, this transformer is ideal for use on most 12 volt model railway systems. Beautifully made. £5.50 plus £ 1.80 post. Plans for mini transmitter, has 6 mile range but has only 15 components, can be picked up on FM radio. Plans £2. Also camera repair manual for Praktica LLC plus parts list with
expioded views of LLC, LTL, L, super TL. £ 13.50. D Martin, 29 St John's Close, Leatherhead, Surrey. · Cushcraft R3 Tri -band trapped vertical antenna. Remote tuned from shack. 1 /2 wave on 20, 15, 10m, no radials required. 2KW traps. Complete with 20 yards hcore control cable. Proven DXer. Total cost
over £250, bargain £ 125. Yaesu FRG7 Rx, digital, fine tuning, SSB filter with mod instructions. Excellent condition. £ 120 ono. Buyer to collect or pay carriage. GM3DPK QTHr. Tel: ( 02612) 5373 after 6pm. · FC902 as new, original packing manual. £95. Shure mic CB43 controlled magnetic, unused boxed. £ 12. Practical Wireless, 50 issues, Amateur Radio, 20 issues, Ham Radio To- day, 22 issues,
QST, 48 issues 1976-1979. Offers. Ace SWR meter plus 0-5W power reading, new boxed. £5. SAE lists, valves, books, spares. All plus postage. Trowell, 'Hamlyn', Saxon Avenue, Minster, Sheerness, Kent ME12 2RP. Tel: ( 0795) 873100.
WANTED
al Circuit diagram or handbook for Eddystone 730/1A receiver. Alan Brooks. Tel: Basingstoke 473202 ext 3054 daytime. · Five pounds paid for circuit diagram of Sharp model IT-51CZ TV camera - can be original or photostat. But must be as complete as possible. Also require manual for Shibaden video tape recorder or circuit diagram showing all socket info. Nev Kirk, 54 Allendale Rd, Rotherham, Yorks S65 3BY. IC22A, Sommerkamp TS580FM or very similar 2m rig. Collect any distance. G4EUW, OTHr. Tel: (020630) 3071 Brightlingsea. · Circuit diagram for Marconi TF2201 oscilloscope, with manual if posa, for copying, all expenses paid. Tel: Penzance ( 0736) 68788. II Back issues of Radio & Electronics World, JanFeb 1982. Can collect. Tel: ( 07914) 2823. la General coverage receiver or low frequency receiver. Tel: Clevedon ( 0272) 87 5181. · Alti meter ex-WD type, barometric with millibars readout in good order. Can exchange good wall hanging barometer, also some dismantled. Also someone to convert Tristar 777 CB to 2829.7MHz for amateur use. Have manual. Alan Edwards ( G3MBL), 244 Ballards Lane, North Finchley, London N12 OEP. Tel: 01-445 4321. · RAF base station key, type ' D' or Marconi marine type 365A. Any semi automatic bug keys by McElroy, Lionel, Vibroplex etc, any condition, damaged or incomplete inc. Details and price to G3TSS. Tel: ( 043) 471 3125. MI Heavy duty tower, can collect and dismantle if necessary, also Trio TS700 TNX. Price, Penyrallt, Llanddeusant, Holyhead, Anglesey, LL65 4AE. Tel: (0407) 730636 after 6pm. · 1KW HF linear, reasonable price. Will collect. G3HMT. Tel: 01-794 2807. · Non-working HRO receivers or parts for spares condition unimportant. Also original HRO power supply units and speaker units. Tel: St Albans 39333. · HRO senior Rx in good clean condition, would buy or exchange for any of the following: Codar AIS 15W HF Tx, Heathkit DX100 100W HF Tx ( both with manuals and in very good clean condition), 33 foot fibre glass vertical antenna in approx 4 foot screw- in sections complete with base mount plate. Would prefer local ( Yorks) exchange. Tel: Harry, Castleford 552862. · Heavy duty rotator, top quality HF beam, tilt over mast or tower, etc. Mervyn Collicott, G1GTC, 10 Tor Rd, Hartley, Plymouth, Devon. Tel: ( 0752) 777777. · Wanted for 10m SSB operation, liner 2or liner 10 Tx/Rx, or WHY for 10 SSB. Tel: G4ANW ( 0730) 61859. · Yaesu YK901 keyboard to use with a Yaesu YR901 CW/RTTY reader. Tel: Colchester 394336. · Crystal sets, valve sets, swan- necked loud speakers, early carbon microphones and Sullivan earphones, also good components and working valves from the 1920s and before. Ron Irving G3SYX, Fir Glen, Beesby Rd, Maltby- le- Marsh, near Alford, Lincs LN13 OJJ. · Bird 43 thruline watt meter inserts. Please ring giving power handling and freq available. Mike Buckley, 12 Ranmore Ave, Croydon, Surrey CRO 5QA. Tel: 01-654 2582. II HP test gear such as 410C, 8405A, 8601A, 250B, 4815A or what have you? Change wheels for AVO wave winder or would consider complete wave winder. Enamelled copper wire, especially fabric covered. Sulzer frequency standard. S J Branson, 111 Park Road, Peterborough PE1 2TR. Tel: ( 0733) 67604.
MI Exchange VIC20 computer C2N cassette manu-
als plus adventure land game for HF Tx/Rx for new class A op, eg FR5OB FLK50B, etc or WHY. Must be in good cond, no mods. GOAIF. Tel: ( 0258) 53670 (evenings). · Decent frequency counter, six or eight digit. D Peach, 56 Basford Park Road, Maybank, Newcastle- Under- Lyme, STS OPS. Tel: ( 0782) 625661. Ex military gear, plugs, sockets, junction boxes, connectors, books, manuals etc. Tel: Jim G4XWD, (0562) 36740. · Handbook and/or workshop manual for Hewlett Packard 4000 valve voltmeter. Buy or loan. Mr R W Goad G4EFA, Flat No2, Osborne Chambers, 59A Osborne Road, Southsea, Hants, P05 3LS. · Manual or copy for Yaesu FT7B also frequency counter YC7B or similar wanted. J C, 56 Clough Lane, Halifax HX2 8SW. Tel: ( 0422) 244046 after 5.30pm. II I require a secondhand LMH AM/FM SSB
transceiver in good condition and good working order. Highgains or 148 Cobra if possible. In aprice bracket between £50-100. Tel: ( 0503) 20798 with details. · FT250/FT200 matching VFO fixed channel kit. DFC CW filter any matching extras also any info on FM board. C E Ladley, Sunnyside, Spinney Close, Grimoldby, Louth, Lincs LN11 8SY. Tel: ( 0507) 828026. II 16mm GSAP Bell and Howell gun camera ( ex Govt) ( American) electric drive with or without lens. Also Pioneer turntable PL340 ( motor unit only required) but complete unit considered. Tel: (0225) 706795 ( Melksham). la 813 valves and bases. G3DWO, 191 Higher Walton Road, Walton- le- Dale, PR5 4HS. Tel: ( 0772) 53810. · KWM380 and T&R bulletins 20's 1930 and some 1940 and 1942. Duplicate OST, CO, bulls from 19305 to sell or swap. SWM wanted for July. Aug of 1959 and Jan 1948, Mar and July 1946 and pre-war. Many SWMs from 1946 to sell or swap. Six metre transceiver wanted. Write Baker, New Bungalow,
Bontnewydd, Aberystwyth, Dyfed. · Ex- Halifax bomber Wop seeks TR1154/55 + data. Reasonably priced. Tel: Felixstowe 284198. · IC202S with linear, also ICBP3 power packs for IC2E or AM, interested in any 2m multimode, reasonable price. Chamberlain G6NUI, 45 Wheatsheaf Gdns, Sheerness, Kent. Tel: ( 0795) 662991. II Base for VCR 139 3 inch cathode ray tube. Contact Harold G8YCG stating price. Tel: (0538) 382550. · Yaesu FT29OR 2m, multimode portable also VHF antenna rotator, cash waiting. lan, 82 Granville Tce, Binchester, County Durham, DL12 8AT. Tel: (0388) 662630. · Would anyone sell a recent obsolete World Radio and TV Handbook to akeen SW DXer who is retired and really can't afford the current price? Brierley, 108 Bolton Road, Rochdale OL11 4QX. Tel: ( 0706) 33108. al Wanted old ARRL Handbooks. Marris, 35 Kingswood House, Farnham Road, Slough, Berks. · Trio TS820S in FB condition, plus ' extras', external VFO, ATU, speaker, plus 12AVO antenna. MacKay, 16 Henley Drive, Timperley, Cheshire, PWA15 6RY. Tel: ( 061 928) 6894. III Urgently required: owner's manual, Kenwood 7600 Tx, will borrow or buy. Alan Kirby, Bradgate, Sessay, Thirsk, North Yorks YO7 3BE. · AR88D Rx, working or not, also 19 set or 19 set chassis, variometer, spares etc and crystal calibrator Mk10. Mr P M Cleaver, 86 Main Road, Dovercourt, Harwich, Essex C012 3LH. Tel: Harwich 502195. la Hall icrafter SX28 required, good condition no mods. Rowbotham, 19 Carisbrooke Road, Bushbury, Wolverhampton. Tel: 481726. · Xtals for two metres 44MHz fundamental frequency manual, or information on Belcom FS1007P transceiver manual or information for Eagle Rx80 communications receiver. Bearcat scanning receiver wanted to buy, and Harvard 4/0T hand-held. M De-Wynter, 2Woodside, Wimbledon, London SW19.
III Oscilloscope dc to 30MHz with manual and circuit diagram, must be complete and in working order. Will pay up to £ 70. All replies answered. A Campbell, 81 Larch Avenue, Bishopbriggs, Glasgow G64 1TB. Tel: ( 041) 772 5280.
62
please mention AMATEUR RADIO when replying to any advertisement
MARCH 1985
FREE CLASSIFIED ADS
II An aerial which will suit the VHF VC10 converter of the Trio R2000. The aerial must be an outside version only and must cover 117 to 174.5MHz. J S Wood. Tel: Clochen 378. · FT707 or FT101E, no fancy prices, urgent. Tel: (0283) 221870. · Wanted: Trio VC10 converter VHF unit also ATU. Tel: ( 0326) 290485. · Datong Morse Tutor. Tel: Keith. ( 0322) 70073. · Codar AT5 Tx, also ARRL handbooks of pre-
1960. Marris, 35 Kingswood House, Farnham Road, Slough, Berks SL2
· Wanted urgently: Trio PSU PS20 for my TS 120V. Please write with details. Mr C Booker, 54 Lodge Hill Lane, Chattenden, Nr Rochester, Kent ME3 8WR. · Loan or copy of manual or circuit for Hallicrafters receiver model S-38 HF Rx. All costs will be met. Tel: Cheltenham 580329.
· Wanted: Trio Kenwood Digital display DG-5 speaker SP520 2m transverter TV 502S. CJ Bean, 11
Nightingale Lane, Earlsdon, Coventry CV5 6AY. Tel: ( 0203) 74811.
II Exchange Trio 9R- 590S mint condition and cash, for Grundig Satellite 3000 21 band comm receiver with SSB unit and S meter. Nash, 39 Fleet Street, Holbeach, Lincs PE12 7AD. Tel Holbeach 22649. · Wanted: 2m transceiver in exchange for 10ft Mirror sailing dinghy (£250) and/or 8ft fibreglass dinghy (£ 100), cash adjustment if necessary. Tel: (058) 470 221 ( Midlands). · £5to the first person who can supply me with a photocopy of the manual for the AEA MBA/RO CW RTTY reader. Have tried everywhere to get one, without success. Needed urgently. Tel: 01-845 4008. · Manual and any ancillary equipment for Marconi instruments sensitive valve voltmeter TF1100, also similar for Telequipment scope model S51B. Will purchase or pay all expenses. Please help. Sutton, 60 Birch Road, Hurstead, Rochdale, Lancs. Tel: ( 0706) 76848.
la Will swap Datong low noise preamplifier 5200MHz, transmit straight through when still in line, and Drae 3 way antenna switch, both little used, as new, for ZX Spectrum 48K micro drive or ZX Interface 1. Tel: ( 051) 334 6859 ( after 5pm). INI Heathkit HFW1 alignment generator in full working and good mechanical and physical condition. No mods. Complete with construction handbook with any update and text correction sheets issued. If by some strange chance an unbuilt kit is available, so much the better. All letters answered. Offers to: Mr Shepherd, 66
Westerland Avenue, Canvey Island, Essex SS8 8JS. · Wanted for Yaesu FT301 transceiver: 600Hz CW filter ( XF90C) and 6KHz AM filter ( XF90B), also external VFO FV301 or other suitable VFO. Tel: St Albans 39333. · Sony CRF230 comm receiver, 23 band with service manual etc. Exchange for air scanner or sell. Letters only please. D R George, 591 London
Road, Thornton Heath, Surrey CR4 6AY. · Racal PRM4031 HF/SSB manpack transceiver or its Larkspur predecessor. Please contact: G4NVX QTHr. Tel: Hereford 265725 ext 247. Early FT101 or 101E, also FC902 or FC707 or similar ATU. Two metre multi- mode rig, base or portable/mobile. Might consider KW 2000A/B. FTV707 frame, any module, also required FRG- 7 but must be very good. and SP901 speaker wanted. David. Tel: ( 04024) 57722 or ( 025587) 663 anytime. · Yaesu 7000 receiver wanted, must be in mint
condition, with instruction book if possible. Also Yaesu FRT7700 ATU FRA7700 indoor active aerial. Tel: 01-272 2465 anytime.
· TA33Jnr or TA32Jnr triband beam antenna or similar. Please contact: R McTait, 22 Nodes Drive, Stevenage. Hens SG2 8AJ. Tel: ( 0438) 721418. la Wanted: Sommerkampts 788 coffee warmer. good condition. Tel Lancaster 34237. II Exchange five piece drum kit with Paiste cymbals ( worth over £900). for FT29OR with Mutek board, nicads and charger, beam and rotator. Or WHY? Tony G1J1X. Tel: Luton 508259.
· Yaesu FRG7 ( digital readout model), also Armstrong 623 LW/MW/FM tuner. Tel: Leeds 663814 ( after 1pm). 11 Regulated power supply 12A output 13.8V. Also linear amp suitable for the car to work IC2E. John Lester G1JUB. Tel: Cuffley 872772. · ORP HF transceiver with digital readout. Prefer SSB/FM, or AM set converted to FM, FT77S, FT707S etc. Will pay cash or part exchange for Avanti PDL II quad beam with rotator and control box and horizontal/vertical antenna switch box.
Sorry, no phone at the moment. R Fensome, 12 The Grove, Luton, Beds LU1 5PE. · Trio/Kenwood AT200/AT230 antenna tuner. Tony G4KHT, QTHr. Tel: ( 0482) 852216. · FDK multi VF011. Contact: R Wade, Tollgate, Cal lington, Cornwall. Tel: Liskeard 83291. · Transmitters required for cadet training. CW or CW-RfT, simple and safe 40m band and possibly 80m and 160m. Offers please to: G4WMT. Tel ( 0245) 469532. · Frequency counter, also trap vertical with radial kit. D Peach G3VXS, 56 Basford Park Road, Maybank, Newcastle-under-Lyme, Staffs ST5 UPS. Tel: ( 0782) 625661.
· FT101/B KW2000/A/B any condition but working if possible, or anything similar, HF Tx/Rx also Commodore 64K computer or handbook to above, also handbook to FT290, must be reasonable. Please write to: J Cavanagh, 190 Liverpool Road, Huyton, Liverpool, Merseyside L36 1RJ. MI Pair of Pye pocket phones, suitable for 70cms. David Crossley G6ZXD, 15 Mylgrove, Roman Way, Coventry. Tel: ( 0203) 412861. la Modern digital short wave/general coverage receiver, no modifications. Cash waiting. Vic, 5 Egremont Road, Exmouth, Devon EX8 1RX. · KW2000 Tx/Ax with PSU and handbook wanted, in good condition. A Evans G3WSJ, 28 St David's Road, Southsea, Hants PO5 1QW. Tel: Ports 816777. · Telereader CWR610E Microwave Modules receive converters for ATV and 136MHz. Mutek BBA500U wideband preamp. MK products SSTV filter board. Tel; Graeme. ( 0642) 318451 ( evenings).
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MARCH 1985
please mention AMATEUR RADIO when replying to any advertisement
63
ADIO
SMALL ADS
PNP Communications Modular terminal units
for RTTY -- MORSE -- AMTOR
PL1 RTTY mod/demod £ 14.50k £ 18.50a MF1 Morse demod £ 12. 50k £ 18.50a FP1 Power supply/amp £ 11. 50k £ 14.50a
a = assembled PCB, k = kit of parts. Software available for -- Dragon VIC20 CBM 64 BBC Amstrad CPC464 Acorn ATOM Please ADD VAT at the current rate.
ACCESS & VISA welcome
62 Lawes Avenue, NEWHAVEN East Sussex BN9 9SB
Telephone (0273) 514465 LARGE SAE for full Catalogue
MORSE TUTOR
£4.00 on cassette. £8.50 on microdrive for Sinclaire Spectrum. 4 to 19 words per minute, variable spacing, variable groups of random letters, numbers qr mixed; Random sentences. own message, single characters and variable pitch. Feedback on screen, printer, or speech (Currah Microspeech 48K only) and repeat facility, 16K and 48K versions on one cassette 48K only on microdrive.
WD SOFTWARE
Hilltop, St. Mary, Jersey, C.Islands Telephone (0534) 81392
XXX ADULT VIDEO CLUB
For the genuine adult films. Available only from ourselves. Ring
0924-471811 (24hrs)
For the intimate details or write
ADULT VIDEO CLUB
P.O. Box 12, Batley, W. Yorks.
MORSE READING PROGS
Work on clean signals without hardware interface ZX81 Ix UNEXRANOED MEMORY Translated code with word and line spaces for easy reading Automatic scroll action £7.00 Ind.
SPECTRUM 16-48K Scroll action with 10 page scrolling memory. instantly accessible page by page £5.00 inc All types variable speeds Feed signal direct into EAR socket
Innehung Dale Mediae, MI Pinehune Perk, Seel Moon Wienbeine, Dorset Mtn OSP.
QSL Cards
Printed on white or colour gloss cards, printed to your own design.
Please send SAE for sample to.
Caswell Press 21 Homethorpe Ave, RedhIII, Surrey
Tel: ( Reclhill) 71023
Telephone the advertising department on: 0277 219876 for details
RTTY/MORSE RADIO SOFTWARE
MTV/MORSE READER For 48K Spectrum The ultimate AX Program, Features include 455 Baud RTTY reception-- Full character set supported Morse reception- auto speed control ( 5-35 WPM). punctuation and wordspace Also includes 40 page text memory, and copy facility for printer.
No extra hardware required - simple connection to radio via computer EAR Socket Price - £5.00 MORSE 77C.MX Program for 48K Spectrum Allows full transceive operation, includes comprehensive morse tutor. No extra hardware required Price £ 7.50 MORSE RX Program for 16K Spectrum and 1K ZX81 Spectrum version includes comprehensive Morse Tutor. Price £ 5.20.
All above Programs 100% Machine Code
P Anderson, Welland*, Mon, Sheldon Mallet, Somerset.
deiumo
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oo SCUT OtTAre`l suppucs
40 TERMINUS RD EASTBOURNE
Tel: (0323) 639351
(opp
Railway Sto.)
Open: Mon-Sat 10-6 (Closed Tues)
Amateur Radio Equipment Yaesù. [ corn Standard Tonna Drue kenpro Halbar WoodS Douglas Daiwa Howes kits & MET antennas
USED AMATEUR EQUIPMENT ? I BUY, SELL & EXCHANGE!
My low overheads mean the best Possible Deal for YOU!
Whether Buying or selling Phone Dave on HORNCHURCH ( 040 24) 57722 ANYTIME, or send
SAE for latest list to
IELEIC -11-F14:»1141.1C13 132 Albany Road, Hornchurch, Essex. RM12 4A0. New Equipment Supplied at Competitive Prices!
Marine Radio also Bought and Sold.
* SERVICE MANUALS *
For ALL Amateur Radio Vintage Wireless Audio Television, Video, Test Equipment etc. etc Thousands stocked LSAE enquiries and quote by return plus FREE catalogue
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MARCH 1985
Telecom Extension Socket Kit. Includes 10m cable, clips, socket & Diagram £6.95.
Cabelec, 14 Tillman Close, Greenley, Milton Keynes, MK12 6AQ.
Eastern Communications
72 -1 31 Cattle Market Street NORWICH
\e/
MON -Eli 9.30-5.30 SAT sies.ace
(0603) 667189
MAIL ORDER
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NEXT ISSUE OF
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ON SALE
Thursday 28th March
A
Armstrong Kurkwood
Developments
10 Willow Green, Grahame Park Estate London, NW9 Tel 01-205 4704
VHF/UHF ABSORPTION WAVEMETER
Covers 120-450 MHz Extremely sensitive Low- profile He
quires PP3 battery
£24 95
DW ELECTRONICS G3 XCF
Amateur Radio Supplies 71 Victoria Rd, Widnes
Tel: 051420 2559 Open Mon- Sat 930-6 ( closed 100pm Thurs) We supply Yaesu, ICOM, Tonne, Jaybeam,
Microwave Modules, Datongs etc
RADIO as. RTTY BOOKS
CONFIDENTIAL FREQUENCIES LIST New 6th Eddition listing thousands of Aero. CW coastal etc Stations world-wide £ 1190 · 80p p&p WORLD PRESS SERVICES FREQUENCIES News RTTY Servies listing by frequencies. GmT 8 Country plus more £6 20 )- 60p p&p CLANDESTINE CONFIDENTIAL New guide to rebel shortwave stations £6.20 · 60p p&p GUIDE TO RTTY FREQUENCIES 4500 stations listed worldwide 6£ 85 - 60p p&p RTTY TODAY beginners guide to RTTY decoding on honre computers, etc £620 · 60p p&p
Free new catalogue of other books now available 2or more books p&p free
INTERPRODUCT UMIT'ED Dept AR3, Stanley, Perth PHI 400 Tel: 073882.575
ALPHA KEYS
Precision engineered keys for the connoisseur. Twin or single paddle keys individually made to be one of the smoothest and lightest movements ever. For the fast operator.
CAVITY WAVEMETER One wavemeter to cover 144MHz to over 2500MHz. Can measure RF as low as 50 Milliwatts with suitable meter. Also now short version to cover 430MHz to over 2500MHz.
10011: WAVEMETER KIT A pre machined cavity to make a 10GHz wavemeter using your micrometer. Can be fixed direct to your wave guide.
COAXIAL RELAY KITS The cavity block is pre machined to take your BNC or N type sockets.
Send large SAE for full information to:
PAUL SERGENT G4ONF 6 GURNEY CLOSE COSTESSEY NORWICH NR5 CHB
Tel: ( 0603) 747782
HIGH PERFORMANCE RF FILTERS
SLIMLINE ATTRACTIVE APPEARANCE
Used by British Telecom, Th or n- EMI, ITT, Telefusion, Grenada etc.
Standard range terminated in Belling Lee plug/socket 175ohms) -- others to order
Model TNF2 Tuned Notch Filters ( Braid 8 Innerl for 2, 10, 15. 20 Metres 8 CB istate which) £7.513 The TNE2 range have avery low insertion toss and very high rejection over the band for which they are supplied They are the best possible answer for aerel borne interference horn a single known frequency or frequency band
Model RBFI-70erns Notch Filter ( inner only) £6.32 Model 881 Braid Breaker £6.32 Also available. 3High Pass models and a-Radar Bhp" fifter for VCRs Please send A4 or C4 stamped addressed envelope for
filters data sheet and price list
All items are manufactured by AKD in UK and carry atwo year guarantee plus 14 day money back promise ( no reason
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MARCH 1985
please mention AMATEUR RADIO when replying to any advertisement
65
ADVERTISERS INDEX
Amateur Radio Exchange P. Anderson Armstrong Kirkwood Development
Cabelec Caswell Press Centre Electronics PM Components PNP Communications WPO Communication
Display Electronics
Eastern Communication Electrovalue DW Electronics G4TNY Electronics
12,13 64
65
65 64 39 52,53 64 57
51
65 39 65 64
ICS Electronics
41
lnterproducts
65
Keytronics
19
Lowe Electronics
4,5
Marco Trading
20
Mauritron Electronics
65
Microwave Modules
Outside Back Cover
Paul Sergent
65
Pinehurst Data Studio
64
Post- a- Part
Inside Front Cover
RSGB
35
RAS ( Nottingham)
39
Sandpiper Communication
18
Selectronics
18
WD Software
64
Southdown Radio
64
Technical Software Thanet Electronics
Used Equipment Centre
34 36,37
30
Viewflint Ltd
50
Vortex
64
R Withers 11, Inside Back Cover
Wood & Douglas
35
ADIO
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MARCH 1985
Well, I've bought a2M Rig that has lots of facilities. Now, how many aerials do Ineed to get the best out of it?
For mobile, the 1/4 wave worked very well in town on my old FM Rig, and it was no problem getting into multi-storey car parks etc. Still, Iwill need something better for motorway and open country.
The 5/8 wave is agood performer-- low angle radiation. Not too long and whippy, like some of the long colinears.
What about S.S.B. mobile? I'll need to be horizontal to do any good. Maybe ahalo and agutter mount would be a good idea.
Imust try some hill top D.X. this summer. That will need a small beam and some means of rotating it.
(sn't forget Fox Hunting -- need aD.F. Loop for that.
must think about portable aerials.
Would be good to get one to do it all)
If you are thinking this way. have alook at the first ever aerial to give you the choice of working modes. Built like a brick outhouse (the Multi P.6) serves all needs on or off the car 2M (and 70cms)
SEE REVIEW IN THIS ISSUE
R WITHERS
COMMUNICATIONS
584 HAGLEY ROAD WEST, OLDBURY, WARLEY B68 OBS (QUINTON, BIRMINGHAM) WEST MIDS. Tel: 021-421 8201/2 ( 24 HR ANSWERPHONE
ARM MULTI P6
MM. VISA
INTRODUCTORY OFFER, £ 29.50 £ 2.00 P&P SAE FOR FURTHER DETAILS ALLOW 3-7 DAYS DELIVERY
771J,AVE D.LES LTD
2METRE MULTIMODE TRANS VERTER FAMT144128·11
'gteeense
FEATURES
* 25 watts Tx output * GaAsFET RF stage * Transmit ALC circuit * 13.8V DC operated
* Repeater shift ( normal, simplex,
reverse) * High level DBM mixer * LED Bargraph Power Meter * RF Vox-- Adjustable delay & manual
override
SPECIFICATION
General Input freq range
Output freq range Repeater shift DC requirements
:28-30M Hz :144-146MHz :Simplex, normal, reverse
:13.8V DC & 6Amps
Transmit Section Output power Input level range ALC range Modes of operation Spuribus outputs
:25 watts +/- 1dB :1/4 to 300mW
:20dB :SSB, FM, CW, AM : -65dB or better
Receive Section
Gain N.F.
3rd order intercept
:20dB min :2dB or better : + 19dBm ( output)
DESCRIPTION
This new transverter has been designed to allow users of existing HF band transceivers to establish afirst-class transceive facility on the 144MHz band. The MMT144/28-R incorporates many new and exciting features which combine to make this product simply superb.
Receive Section An NEC GaAsFET is employed in anoise- matched configuration feeding ahigh level double balanced mixer via abandpass filter. IF gain is achieved by aJFET post amplifier. This combination produces agood signal to noise ratio, excellent immunity to overload and cross modulation, resulting in arugged receive system having athird order output intercept point of + 19dBm. Two separate low- noise oscillators, operating at 116.00 and 115.40MHz are included, running from aregulated 8.2 volt supply. Selection of the wanted oscillator is achieved by aquad op- amp circuit, controlled by the front panel mounted MODE switch. This provides simplex, repeater and reverse repeater operation. The output of each oscillator feeds aJFET buffer amplifier via the quartz crystal which acts as a filtering element to reduce amplitude noise and reciprocal mixing products. The resultant high level injection is extremely pure and free from harmonics.
Transmit Section The incoming 28MHz signal, in the range V. to 300mW, is initially fed to the RF VOX circuit, ALC control circuit and the input level control. This signal is then fed into apair of MOSFETs in abalanced mixer configuration, together with the local oscillator injection, to produce the wanted signal in the range 144-146MHz. This signal is then amplified by several linear stages up to the specified output power of 25 watts. A visual indication of relative output power is provided by afront panel mounted LED bargraph display. A rear panel mounted level control allows the user to adjust the sensitivity of the transverter to suit the transceiver in use, and afront panel mounted RF VOX delay control allows adjustment to suit SSB/FM modes. The ALC circuit has a20dB dynamic range and has been incorporated to ensure that atotally clean signal is produced by the transverter. This is aparticularly useful feature which will virtually eliminate compressed signals and the resultant problems caused to local stations.
PRICE : £215 inc VAT (p +p £ 3.50)
HOURS:
MICROWAVE MODULES LTD
VISA
MONDAY -- FRIDAY Brookfield Drive, Aintree, Liverpool L9 7AN,
9-12.30. 1-5.00
England.
AR
Telephone: 051-523 4011.
Telex: 628608 MICRO G.
Foxit FXPDFA 1.2 PDF Compressor 8.2.14.09