SEA of Delaware SEA157 VHF Marine Radiotelephone/DSC Controller User Manual April 5 2000 FIRST DRAFT

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Document Description	ta8man users manual theory of operation and tuneup procedures
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Date Submitted	2000-04-12 00:00:00
Date Available	2000-05-16 00:00:00
Creation Date	2000-04-12 11:47:36
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Document Lastmod	2000-04-12 11:47:50
Document Title	April 5, 2000 FIRST DRAFT
Document Creator	Microsoft Word 8.0
Document Author:	SEA INC.

April 5, 2000 FIRST DRAFT
4/10/2000 1st REV
SEA INC OF DELAWARE
PRELIMINARY MAINTENANCE MANUAL
VHF FM RADIOTELEPHONE/DSC CONTROLLER
MODEL SEA 157
(c) Copyright 2000
SEA, Inc.
All rights reserved.
SEA, Inc.
7030 220th St. S.W.
Mountlake Terrace, Washington
(425) 771-2182
FAX: (425) 771-2650
98043
**IMPORTANT**
NOTICE TO INSTALLERS
-----------------------------------------------------------------NOTE:
The safe compass distance for this equipment (As defined in
Paragraph 29 of IEC Publication 92-101, Third Edition):
SEA 157 VHF FM TRANSCEIVER/DSC CONTROLLER = 2.0 meters
------------------------------------------------------------------
TABLE OF CONTENTS
1.
PAGE
INTRODUCTION............................................1-1
2.
SEA 157 SPECIFICATIONS..................................2-1
2.1 General............................................2-1
2.2 Transmitter........................................2-1
2.3 Receiver...........................................2-2
2.4 Mechanical.........................................2-3
2.5 DSC controller.....................................2-4
3.
OPERATING THE SEA157....................................3-1
3.1 Front panel controls...............................3-1
3.2 Display............................................3-1
3.3 Push to talk.......................................3-1
3.4 Radiotelephone operating system functions..........3-2
3.5 Digital selective calling operating system.........3-6
3.6 Receiving a call...................................3-8
3.7 Inputting position data and time...................3-8
3.8 Programming the DSC ID (MMSI)......................3-9
3.9 Programming the DSC Address Book...................3-9
3.10 Using test, calibration and diagnostic utilities...3-10
3.11 Master USA frequency list..........................3-11
3.12 International Channel list.........................3-12
3.13 Weather Channel list...............................3-12
4.
INSTALLATION............................................4-1
4.1 Preliminary check..................................4-1
4.2 Shelf or overhead mounting.........................4-1
4.3 Bulkhead mounting..................................4-1
4.4 Power supply wiring................................4-1
4.5 Antenna wiring.....................................4-1
4.6 External speaker wiring............................4-2
4-7 NMEA 0183 input wiring.............................4-2
5.
THEORY OF OPERATION.....................................5-1
5.1 Frequency synthesizer..............................5-1
5.2 Modulation circuit.................................5-2
5.3 Receiver circuits..................................5-2
5.4 Transmit amplifiers................................5-3
5.5 Antenna interface circuits.........................5-4
5.6 Automatic RF power control and TX logic............5-4
5.7 TX Logic detector..................................5-5
5.8 Power and Audio circuits...........................5-5
5.9 Microcomputer circuitry............................5-5
5.10 Keypad/keypad lighting.............................5-6
5.11 Display/display lighting...........................5-6
6.
MAINTENANCE.............................................6-1
6.1 General............................................6-1
6.2 Recommended test equipment.........................6-1
6.3 Basic performance tests............................6-2
6.4 Transmitter alignment..............................6-4
6.5 Receiver alignment.................................6-5
7.
SCHEMATICS..............................................7-1
LIST OF FIGURES
FIG. ___________________DESCRIPTION___________________
Page
2.1
Front view of SEA 157.........................2-5
2.2
Rear view of SEA 157..........................2-6
4.1
Outline Dimensions of SEA 157.................4-2
4.2
Flush Mount Kit Drill Template for SEA 157....4-5
6.1
Transmitter test setup........................6-10
6.2
Receiver test setup...........................6-11
7.1
Functional block diagram......................
7.2.1
RF Mainboard schematic diagram, Sheet 1.......
7.2.2
RF Mainboard schematic diagram, Sheet 2.......
7.2.3
RF Mainboard schematic diagram, Sheet 3.......
7.2.3
RF Mainboard schematic diagram, Sheet 4.......
7.2.3
RF Mainboard schematic diagram, Sheet 5.......
7.3
VCO Circuit Board schematic diagram...........
7.4
Receiver Circuit Board schematic diagram......
1
INTRODUCTION
This SEA
157 Service Manual provides detailed technical
information for use by installation and service technicians.
General
operating
instructions
and
installation
drill
templates are provided in the SEA
157 Operator's Handbook
(SEA P/N OPR-157) supplied with each SEA 157.
SEA continually strives to improve its products so that we
may better serve our customers.
SEA reserves the right to
make changes to SEA 157 specifications, hardware, software
or documentation at any time without notice.
SEA's Marine Service Department is always available
provide additional help with technical difficulties.
to
Please call SEA's Service Department to obtain a Return
Authorization Number (RA#) before shipping equipment to SEA.
Service
parts
are
available
through
SEA's
Marine
Sales/Service Departments. Please order parts using SEA part
numbers found in Section 8.
1-1
2
2.1
2.2
SEA
157 SPECIFICATIONS:
GENERAL
FREQUENCY RANGE:
TX 155-159 MHz
US TX 156.0-157.5 MHz
RX 155-164 MHz
FREQUENCY RESOLUTION:
25 KHz
CHANNELS:
All US, Canadian, Int'l
plus 10 WX
POWER REQUIREMENT:
NOTE: Basic radio Circuitry
operates at 12 volts.
Voltage, 12 V +30, -10%
13.6 volts nominal negative ground.
CURRENT:
(12 Volt operation) Max TX:
5.5 amps (25W)
1.0 amps (1W)
RX (STBY) 0.4 amp
RX (Max Audio 1 amp
FUSES:
(12 Volt operation) 7.5 amp, external line
TRANSMITTER
EMISSION:
16K0G3E (Voice)
13K5G2B (DSC)
POWER OUTPUT:
25W, 1W into 50 ohms
SPURIOUS EMISSIONS:
-80 dB or better
SPURIOUS RADIATION:
Complies with FCC 80.211(f)
AUDIO HARMONIC DISTORTION:
10% max.
AUDIO FREQUENCY RESPONSE:
+1,-3 dB of +6 dB/octave
preemphasis 300-3000 Hz
HUM AND NOISE:
50 dB (EIA)
FREQUENCY DEVIATION:
5 KHz max. peak
CARRIER FREQUENCY STABILITY:
+5 ppm, -30 to +60 C
(FCC, EIA)
TRANSMITTER ATTACK TIME:
< 100 milliseconds (EIA)
2-1
(EIA)
2.3
RECEIVER
FREQUENCY RANGE:
Simplex 155-159 MHz
Semi-duplex 159-164 MHz
INTERMEDIATE FREQUENCIES:
21.4 MHz, 450 KHz
SENSITIVITY:
< 0.3 uv for 12 dB SINAD
AUDIO FREQUENCY RESPONSE:
Within +1,-3 dB of 6 dB per
octave deemphasis from 3003000 Hz (EIA)
AUDIO OUTPUT:
4 W at less than 10%
distortion into external
4 ohm load. 2 W internal
HUM AND NOISE:
Unsquelched -45 dB (EIA)
Squelched -55 dB (EIA)
ADJACENT CHANNEL SELECTIVITY: -80 dB @ 25 KHz
-85 dB @ > 50 KHz (EIA)
SPURIOUS EMISSION, RADIATION: Complies with FCC, and EIA
SQUELCH SENSITIVITY:
Threshold: .2 uv max. (EIA)
Tight: max 10 dB above
reference sensitivity (EIA)
RECEIVER ATTACK TIME:
Less than 100 msec (EIA)
RECEIVER CLOSING TIME:
100 msec typical
250 msec max
SCAN RATE:
Max 10 channels/second
MODULATION ACCEPTANCE:
6 KHz minimum
7 KHz typical
2-2
(EIA)
2.4
MECHANICAL
DIMENSIONS:
(HEIGHT-WIDTH-DEPTH)
In: 3.6 x 9.6 x 3.1
mm: 91 x 244 x 79
WEIGHT:
Lbs: 3.0
Kgs: 1.4
2-3
2.6
SEA
157 VHF DIGITAL SELECTIVE CALLING CONTROLLER
The
VHF
Digital
Selective
Calling
Controller
incorporated into the SEA
157 VHF Radiotelephone has
been designed to comply with all FCC regulations given
in 47 CFR 80.225. This encompasses compliance with the
following documents which are included for reference:
80.225(a)
80.225(a)
ITU-R Recommendation M.493-9 Class D
RTCM Paper 56-95/SC101-STD
2-4
3.
OPERATING THE SEA
157
3.1
FRONT PANEL CONTROLS
Figure 2.1 illustrates the front panel of the SEA
157.
The
functions of the individual controls and indicators are listed
below.
3.1.1
ROTARY CONTROLS
The rotary control of the SEA 157 is used for several radio
functions. It can be used to adjust the channel, volume, squelch
and backlighting from the normal radio operating mode. In other
modes, such as editing the DSC address list, it is used to select
characters of the alphabet and in the setup mode it is used to
select from a list of setup options.
The user can set the default mode for the rotary control using the
setup menu. The rotary control will return to the default state 5
seconds (user selectable) after the last adjustment is made.
Squelch mode adds 5 seconds to this timeout to allow for squelch
on/off time while adjusting the level.
3.1.2
KEYPAD
A 15 key backlighted keypad is provided which, together with the
LCD graphics display, provides an operating system which permits
the operator to control both the radiotelephone and digital
selective calling (DSC) features of the SEA 157.
3.2
DISPLAY
The LCD display used in the SEA 157 is a LCD display with a 14
segment 8 character display, 7 segment 3 digit display and 17
annunciator flags.
The display is backlighted and is used
interactively with the keypad to provide an effective operator
interface to the radiotelephone/DSC functions of the SEA 157.
3.3
PUSH TO TALK
The radio is put into transmit mode by pressing the microphone
push to talk key. It remains in transmit mode until the push to
talk switch is released or until the internal 5 minute timer
expires. The TX annunciator is displayed during transmit. Note
that the internal DSC controller can also initiate transmissions
independent of the push to talk switch on the microphone.
3-1
3.4
3.4.1
RADIOTELEPHONE OPERATING SYSTEM FUNCTIONS
CHANNEL SELECTION
The rotary control is used to select the channels. Push the MODE
key until the CH flag is on, then use the rotary control to select
the desired channel. This operates within the current channel list
and wraps around at both ends of the list. eg. from channel 88A to
channel 1 when moving up through the list.
The 8 digit display shows the channel name while in this mode. The
display reverts to the current Lat/Long after 5 seconds of no
activity.
The numerical keys can also be used to select a channel directly.
The radio supports the standard 2 digit VHF channel list. To
enter a channel press the channel number with leading digits to
switch to the channel immediately. If a single digit is pressed
and you delay for 5 seconds the radio will switch to that single
digit channel. For example, to go to channel 23 press 2,3 to
switch to the channel immediately. Press 0,5 to go to channel 5
immediately. Press 6 and pause for 5 seconds and the radio will
switch to channel 6.
In the Weather list the operation is similar to this, if the 2
through 9 keys are pressed in WX mode the channel is selected
immediately, because there are only 10 weather channels available.
If 0 is pressed then the channel number from 1 to 9 is waited for
with the first digit blinking. If 1 is pressed it waits for the 0
if you want to go to channel 10 or times out after 5 seconds and
goes to channel 1.
3.4.2
ON-OFF/VOLUME CONTROL
The rotary control is used for this function. Push the MODE key
until the VOL flag is on, then use the rotary control to set the
desired volume level. The squelch is temporarily turned off while
the volume level is being adjusted so that the volume level can be
monitored. The SQL setting is returned to the user selected state
5 seconds after the last rotary control adjustment.
3.4.3
SQUELCH CONTROL
Push the MODE key until the SQ flag is on, then use the rotary
control to adjust the squelch level as desired. The squelch will
be temporarily activated so that you can listen to the effect the
current setting will have. The squelch is returned to the user
selected state 10 seconds after the last adjustment.
Pressing FUNC-2 will toggle the squelch on and off, as indicated
by the SQL flag on the display.
3-2
3.4.4
CHANNEL LIST SELECTION
Pressing FUNC-8 will toggle the radio between the USA and INT
channel lists. The radio will go to the last used channel in the
selected list. If it is pressed while in the Weather list it will
return to the previous list.
Pressing FUNC-3 will switch the radio to the weather list,
remembering the current list and channel. Pressing FUNC-3 again
will return the radio to the previous channel list and channel.
3.4.5
EMERGENCY CHANNEL SELECTION
Pushing the CH16 key at any time, in any state of radio operation,
will go to CH16 in the current list, or in the case of pressing it
while in the Weather list it will go to CH 16 in the last used
list.
3.4.6
TRANSMITTER POWER CONTROL
Pressing FUNC-1 toggles the transmitter power level on channels
that allow 25W transmission. On channels that only allow 1W this
function does nothing. When transmitting on a 1W only channel the
FUNC key can be held down while transmitting to temporarily switch
to 25W. The display will show the 1W flag when in the 1W mode and
the 1W flag will be off when 25W is active.
3.4.7
DUAL WATCH
The SEA 157 has two watch modes available. Dual watch is initiated
by pressing FUNC-6 briefly while on the primary channel you want
to monitor. The 8 character display will say 'DUAL 16' and channel
16 will be checked every 2 seconds while there is no activity on
either channel. If there is activity on the primary channel or on
channel 16 the radio will hold on that channel until there is no
activity for [hangtime] seconds. This behavior can be changed so
that channel 16 always has priority by using the Dual Watch setup
menu option.
The channel number display will indicate which channel it is
operating on. Pressing PTT will exit dual watch and switch to the
current channel.
If Dual Watch is selected while on channel 16 it will not start a
dual watch.
The Triple Watch function is started by pressing FUNC-6 for longer
than 1 second on the primary channel that you want to monitor. The
display will show 'TRIPL 16' and will check channel 16 and the
Priority channel every 2 seconds. By default channel 16 has
priority, but this behavior can be changed using the Triple Watch
setup menu option.
3-3
3.4.8
SEEK
The Seek mode scans all channels in the selected list (USA/INT/WX)
and is started by pressing FUNC-5 for more than 1 second. The
display will show 'SEEKING' and the radio will scan all the
channels in the current list.
A Priority seek is started by first selecting the PRI channel
using FUNC-9 and then starting a Seek. The PRI channel will be
checked in-between every channel.
Starting a seek after pressing CH16 will seek all channels and
check channel 16 in-between each channel.
3.4.9
SCAN
The Scan function is started by briefly pressing the FUNC-5. The
display will show 'SCANNING' and the radio will scan the channels
that are members of the Scan List (indicated by the MEM flag). It
will scan the channels, and hold on an open channel for the user
selectable hangtime after the channel becomes inactive. Channel 16
is always included in the scan list, no matter what its MEM list
state.
Only the memorized channels in the current list will be scanned.
A Priority scan mode is started by first selecting the PRI channel
using FUNC-9 and then pressing FUNC-5. The PRI channel will then
be checked in between every channel in the scan list.
Starting a scan after pressing CH16 will scan channel 16 in
between every channel in the scan list.
3.4.10
PRIORITY SCAN
If the priority channel is selected BEFORE entering the scan mode,
the receiver scans the priority channel in between each channel.
3.4.11
SCAN CHANNEL PROGRAMMING
The FUNC-4 MEM function adds or removes the current channel from
the scan list. The MEM flag will be on if the current channel is
included in the scan list. The memorized channels can be scanned
by using the FUNC-5 scan function.
3.4.12
PRIORITY CHANNEL PROGRAMMING
Briefly pressing FUNC-9 switches the radio to the programmed
priority calling channel. Pressing FUNC-9 for more than 1 second
will set the current channel as the priority channel, as indicated
by the PRI flag being on when then channel is selected. The
factory default for the PRI channel is channel 9, in the USA
channel list.
The priority channel is also used by the Triple Watch mode and the
Priority scan and seek modes.
3-4
3.4.13
SEARCH MODE PROGRAMMING
Enter the setup menu using FUNC-MODE and then select the ‘SEARCH’
function with the rotary control. Press MODE to adjust the search
mode operation. Use the rotary control to select from 2 styles of
search mode operation for Seek and Scan modes:
[ACt]1 - Stop on the active channel until squelch closes
[ gO]2 - Stop on the active channel for 2.5 seconds and then
continue the search.
3.4.16
PRIORITY/DUAL SCAN MODE PROGRAMMING
Enter the setup menu using FUNC-MODE and then select the
‘DUALWTCH’ function with the rotary control. Press MODE to adjust
the Dual Watch mode operation. Use the rotary control to select
from 2 styles of dual watch:
[ACt]1 - Stop on first active channel
[C16]2 - CH 16 always has priority, and is checked even when there
is activity on other channels
3.4.17
SCAN HANG TIME PROGRAMMING
Enter the setup menu using FUNC-MODE and then select the
‘HANGTIME’ function with the rotary control. Press MODE to adjust
the hangtime. Use the rotary control to select the amount of time
for the radio to stay on a channel after the squelch closes, in
0.5 second increments from 0 to 20 on the display (0 to 10
seconds).
3.4.18
ADJUSTING THE BACKLIGHTING LEVEL
Push the MODE key until the DIM flag is on, then use the rotary
control to adjust the brightness level. The display will show the
brightness level.
3.4.19
KEY BEEP CONTROL
Enter the setup menu using FUNC-MODE and then select the ‘BEEP
LVL’ function with the rotary control. Press MODE to adjust the
beep level. Use the rotary control to select the beep volume
level, 0-15. The radio will emit a short test beep for every turn
of the rotary control.
3.4.21
MODIFYING CHANNEL NAMES
Select the channel to be edited using the rotary control or direct
channel entry. The channel’s current ASCII tag will be displayed
for 3 seconds. Select the channel editing function by pressing
FUNC-MODE and selecting the ‘CHANNAME’ option. Press MODE to edit
the ASCII tag for the channel. The display shows the current radio
3-5
channel with the first digit of the channel’s ASCII tag blinking.
Use the rotary control to select the character and press MODE to
move to the next digit. Pressing FUNC will move to the previous
digit, and pressing any other key will exit from the channel edit
without saving changes. Once the final digit has been edited and
MODE key pressed the new channel tag will be saved to non-volatile
memory. A character set of upper case A-Z, numbers 0-9 and a space
are available for the selection.
Pressing CH16 or DIST in this mode will immediately exit the
editing mode and activate their respective functions.
3.5
3.5.1
DIGITAL SELECTIVE CALLING OPERATING SYSTEM
DISTRESS CALLING
Pressing the DIST key for 3 seconds will cause the radio to enter
the DSC distress mode. The radio will switch to channel 70 and the
display will show 'DISTRESS' and ‘PRESSPTT’ while waiting for PTT
to be pressed, if the current position is known (a GPS or other
device must be attached to the NMEA input). The radio is now ready
to transmit the distress call by pressing PTT. Press PTT to send
the distress call - the radio will wait for channel 70 to be
clear, displaying 'BUSY' while it is waiting, and then transmit
the distress call. The radio will then wait for an acknowledge and
the display will alternate between ‘DISTRESS’ and ‘WAIT ACK’. If
none is received within 3.5 to 4.5 minutes then the distress call
will automatically repeat until an acknowledge is received.
Pressing PTT will resend the distress call immediately. When an
acknowledgement is received then the radio beeps and switches to
channel 16. The display switches to 'DIST ACK' and the radio
enters normal operating mode.
The distress call can be canceled by pressing the CH16 key.
If the current location is unknown the display will switch to '----W' with the first digit blinking. Use the rotary control or the
numeric keys to select the correct location, using MODE to move to
the next digit. When the Longitude is entered the E/W digit will
flash and the rotary control will select E or W. When MODE is
pressed after the E/W is selected the display changes to ' -- --N'
with the first digit blinking. Enter the Latitude, using the
rotary control to select the N/S and press MODE to continue. You
will then be prompted to enter the time when the position was
valid, the display will show ‘00-00‘ with the first digit
blinking. After entering the time the display will change to show
‘DISTRESS’ and ‘PRESSPTT’ while waiting for PTT to be pressed.
The entry of Latitude/Longitude/Time can be skipped in an
emergency by holding down the DIST key for 5 seconds. The display
will show ‘DISTRESS’ and ‘PRESSPTT’ while waiting for PTT. Please
note that the DSC call will indicate that the position is unknown.
3-6
3.5.2
DSC CALL
The SEA 157 also supports All ships and Individual call DSC
transmissions. Select a simplex channel to use for voice
communications after the call and press FUNC-0 to initiate a DSC
call.
The radio will switch to channel 70, the DSC calling
channel, and will display the last DSC call that you placed or
'ALL SHIP' if no previous call has been made.
Pressing FUNC-0 while on a receive only channel is not allowed and
the radio will beep twice to indicate an error. You must first
select a channel to use for voice communications after the DSC
call is acknowledged and then press FUNC-0 to select the DSC
station to call.
3.5.2.1
ROUTINE INDIVIDUAL DSC CALL
Select the DSC calling mode using FUNC-0, and then use the rotary
control to select the DSC call to make from the list of DSC
addresses previously entered using the DSC Address programming
mode from the SETUP menu. Once the desired DSC call is selected
push the PTT button to transmit the call. The radio checks for a
clear channel and transmits the call. If the channel is busy the
radio will alternate between displaying 'BUSY' and ‘DSC CALL’
while it waits for the channel to clear. Once the channel is clear
the call will be transmitted automatically.
The DSC mode can be aborted at any time by pressing the MODE key
or it will revert to normal radio operation if there is no user
activity for 30 seconds.
When an individual call is sent the unit will wait for an
acknowledge to be received before switching to the selected
channel. While waiting for the acknowledge the radio will
alternate between showing ‘DSC CALL’ and ‘WAIT ACK’, and the call
can be resent immediately by pressing PTT. Once the acknowledge is
received the radio will switch to the selected voice channel and
the display will show ‘ABLE’ or ‘UNABLE’, depending on the
response received, until the used takes action such as keying the
radio or changing channels.
3.5.2.4
ALL SHIPS CALLS
Select the DSC calling mode using FUNC-0 and then use the rotary
control to select ‘ALL SHIP’ from the menu. When an All Ships call
is made the radio does not wait for an acknowledge, it switches to
the selected voice communications channel immediately after the
call is sent.
3-7
3.6
RECEIVING A CALL
To receive DSC calls the radio must be monitoring channel 70. When
a DSC call is received the radio will beep in a unique fashion to
indicate either a Distress call or a normal call.
When a distress or distress relay call is received the radio will
automatically switch to high power on channel 16 and the display
will show 'DISTRESS' or 'DIST RLY'. An alarm tone will sound until
the CH16 key is pressed to silence it, or 2 minutes have passed.
When an all ships or geographic call is received the radio will
beep and switch to the voice channel specified by the calling
station. The display will show 'ALL SHIP' or 'GEO CALL' while on
the selected channel. The display will revert to its normal
operating mode when the channel selector is changed or a key is
pressed.
When an individual call is received additional action may be taken
automatically, depending on the setting of the DSC Receive mode
setup menu:
If an automatic reply has been selected in the Setup menu it will
be sent and the radio will switch to the voice channel selected by
the calling station. The display will alternate between 'INDIVID'
and the name or DSC ID of the caller until the user selects
another channel.
If the manual reply mode is selected then the radio will display
'ABLE' and beep once per second. You can select 'UNABLE' using the
rotary control. Pressing PTT will transmit the acknowledgement and
the radio will then switch to the channel selected by the calling
station if ‘ABLE’ was sent. If ‘UNABLE’ was sent it will stay on
channel 70.
If the Manual+Timeout DSC Receive mode is selected then the radio
will display 'UNABLE ' and beep until 'ABLE ' is selected using
the rotary control and PTT is pressed. If 4.5 minutes pass without
the user selecting 'ABLE' then the radio will transmit the unable
to comply message and remain on channel 70.
While on the selected voice channel the display will alternate
between showing 'INDIVID' and the name or DSC ID of the caller.
The name is displayed if the caller’s MMSI is in the address book.
3.7
INPUTTING POSITION DATA AND TIME
Press FUNC-MODE and use the rotary control to select the ‘SET LOC’
menu. Press MODE and the display will show '--- --W' with the
first digit blinking. Use the rotary control or the numeric keys
to enter the correct longitude, using MODE to move to the next
digit. When longitude is entered the E/W digit will flash and the
3-8
rotary control will select E or W. When MODE is pressed after the
E/W is selected the display changes to ' -- --N' with the first
digit blinking. Enter the Latitude, using the rotary control to
select the N/S and press MODE to continue. You will then be
prompted to enter the time that the position was valid at, the
display will show ‘00-00‘ with the first digit blinking. After
entering the time the radio will return to receive operation on
the current channel.
If a GPS receiver is attached the display will show the last valid
location and time. If new valid data is received from the GPS it
will take precedence over what is entered above. This function
should only be used when there is no GPS attached, or when the GPS
data is invalid.
3.8
PROGRAMMING THE DSC ID (MMSI)
Press FUNC-MODE and use the rotary control to select the ‘DSC ID’
menu. Press mode and the display will show the current DSC ID with
the first digit blinking if you are allowed to change the DSC ID.
The DSC ID is allowed to be changed twice after factory
initialization. If the ID can be changed then the first digit will
blink and the rotary control should be used to select the digits,
using MODE to move to the next digit. Pressing CH16 or DIST will
exit the setup mode immediately with no changes being saved.
3.9
PROGRAMMING THE DSC ADDRESS BOOK
Press FUNC-MODE and use the rotary control to select ‘ADDRESS’
from the menu. Press MODE and the 3 digit display shows an 'A' in
the left digit and the address bin number 1-10 in the right 2
digits. The 8 character display shows the current ASCII name for
the selected bin or ‘BLANK’ for a blank entry. Use the rotary
control to select the address bin to enter or change and press
MODE again. The 8 digit and 3 digit display will show the DSC ID
and the first digit will blink. Use the rotary control to select
the digits, pressing MODE to move to the next digit until all
digits have been entered. FUNC will move the cursor back 1 digit.
Once all the digits have been entered the display will then show
the name of the address bin, with the first digit blinking. Use
the rotary control to select the characters, pressing MODE to move
to the next digit and FUNC to move to the previous digit. Pressing
CH16 will abort the edit and go to Channel 16.
When the DSC ID and name have been entered the radio returns to
the Address list review mode to allow multiple addresses to be
easily added to the radio. You can exit from this mode by pressing
CH16.
3-9
3.10 USING TEST, CALIBRATION AND DIAGNOSTIC UTILITIES
Enter the service menu by pressing FUNC-MODE and entering the
service menu activation code (contact the factory with the radio’s
serial number to receive the activation code).
A menu allowing you to adjust the clock frequency, 1W power level,
25W power level and transmit the DSC tones and dot patterns.
During
all of the service menus PTT is active so that the
transmitter can be tested.
3.10.1 CLOCK TUNING
Select the ‘CLKTUN’ menu and press mode. The display will show the
clock frequency adjustment value (0-200, 100 is normal setting).
Use the rotary control to adjust the value and press MODE to store
the new setting and exit the adjustment mode.
3.10.2 POWER LEVEL ADJUSTMENT
Select the ‘1W ADJ’ or the ‘25W ADJ’ mode from the service menu.
Press MODE to enter the adjustment menu. The 3 digit display will
show the current power level control setting and the right 3
digits of the 8 character display will show the forward power
reading. Pressing PTT will transmit and the ALC will adjust the
power level to be equal to the setting selected. Press MODE to
store the setting to non-volatile memory and exit the service
menu.
3.10.3 DSC TONE TRANSMIT
Select the ‘DSC DOT’, ‘DSC 1300' or ‘DSC 2100' selection from the
service menu. Press MODE and the 3 digit display will show ‘ON’,
and pressing PTT will transmit the selected DSC tone or dot
pattern. Press MODE to exit the service menu.
3-10
3.11
USA CHANNEL LISTING
Channel
S/D
SHIP TX
--S
156.050
156.050
156.100
156.150
156.200
156.250
156.300
156.350
156.400
156.450
156.500
156.550
156.600
156.650
14
15
16
17
18A
19A
20
20A
21A*
22A
23
23A*
24
25
26
27
28
156.700
156.750
156.800
156.850
156.900
156.950
157.000
157.000
157.050
157.100
157.150
157.150
157.200
157.250
157.300
157.350
157.400
RX Only
(VTS), U.S. Only, Port Ops
Intership Safety
Commercial
Commercial, Non-Commercial
Commercial, Non-Commercial
Commercial
(VTS), Commercial
(VTS), Port Ops
Bridge-to-Bridge, Navigational
(Manual override to 25 watts)
(VTS), Port Ops
RX only (Coast to Ship Environmental)
DISTRESS AND CALLING
Maritime Control
Commercial
Commercial
Port Ops
Port Ops, Intership
U.S. Govt ONLY (USCG)
U.S. Coast Guard
Public Correspondence
U.S. Govt ONLY
Public Correspondence
Public Correspondence
Public Correspondence
Public Correspondence
Public Correspondence
Channel
S/D
SHIP TX
Ch. Designation
60
61A*
62A
63A
64
65A
66A
67
--S
--S
156.025
156.075
156.125
156.175
156.225
156.275
156.325
156.375
156.425
156.475
156.525
156.575
RX Only
Public Correspondence
RX Only
Port Ops, Commercial
Public Correspondence
Port Ops
U.S. Only, Port Ops
Commercial, "Bridge-to-Bridge" Nav
(Manual override to 25 watts)
Non-Commercial
Non-Commercial
Digital Selective Calling (DSC)
Non-Commercial
01
01A
02
03A
04A--05A
06
07A
08
09
10
11
12
13
68
69
70
71
Ch. Designation
Port Operations, Commercial
RX Only
3-11
72
73
74
77
156.625
156.675
156.725
156.875
78A
79A
80A
81A*
82A*
83A*
84
85
86
87
88
88A
156.925
156.975
157.025
157.075
157.125
157.175
157.225
157.275
157.325
157.375
157.425
157.425
Non-Commercial
Port Ops
Port Ops
Port Ops, Intership Only
(Manual override to 25 watts)
Non-Commercial
Commercial
Commercical
U.S. Govt ONLY
U.S. Govt ONLY
U.S. Govt ONLY
Public Correspondence
Public Correspondence
Public Correspondence
Public Correspondence
Public Correspondence
Commercial Intership
3-12
3.20 International Channel listing
NOTE: Amended International Channel List is identical
to the SEA 157 International Channel List with the
following exceptions:
Channel
S/D
SHIP TX
Ch. Designation
01
156.050
Canada Public Correspondence
.................................................................
02
156.100
Canada Public Correspondence
.................................................................
04A
156.200
Canada Public Correspondence
.................................................................
60
156.025
Canada Public Correspondence
.................................................................
62A
156.125
Canada Public Correspondence
................................................................
3.21 Weather Channel listing
Bin
10
Smpx
TX
25W SHIPRX
162.550
162.400
163.475
161.275
161.650
162.775
162.425
162.450
162.500
162.525
SHIPTX
3-13
Tag
WEATHER 1
WEATHER 2
WEATHER 3
WEATHER 4
WEATHER 5
WEATHER 6
WEATHER 7
WEATHER 8
WEATHER 9
WEATHR 10
4.
INSTALLATION
4.1
PRELIMINARY CHECK:
Prior to installation, the transmit frequency, peak frequency
deviation and RF power output level should be checked on a
calibrated FM service monitor or equivalent equipment.
See
Section 6 of this manual for more detailed procedures.
4.2
SHELF OR OVERHEAD MOUNTING:
See Figure 4.1 for dimension drawings of SEA
4.3
157.
BULKHEAD MOUNTING:
A special bulkhead mounting bracket (SEA P/N KIT-0157-30) is
available from SEA which permits through-bulkhead mounting of the
SEA 157. The required depth behind the bulkhead is approximately
11.5 inches (290 mm). Contact SEA at (425) 771-2182.
4.4
POWER SUPPLY WIRING:
Use a 12 volt +30%/-10% (10.8 to 15.6 vdc) DC power source for
proper operation.
Direct connection to the battery or power
supply is recommended. Connect the RED positive (+) power lead to
the positive supply rail.
The BLACK negative (-) power lead
connects to the negative supply rail. NOTE: The chassis of the
SEA 157 is connected to the negative supply rail.
CAUTION: If the power wires are connected backward, i.e.,
reverse
polarity
power
is
accidentally
applied
to
the
radiotelephone, the fuse will blow.
It is also likely that the
reverse-polarity protection diode, D2, which is near the power
lead connections on the main circuit board will also be damaged.
Application of voltages greater than the maximum rated voltage
will produce the same result. (Refer service of this equipment to
a qualified technician.)
4.5
ANTENNA WIRING:
Use only the best available antennas, 50 ohm coaxial antenna
feedline cable and connectors.
The antennas must be vertically
polarized. The antenna cables should be terminated with properly
installed PL-259 (Type UHF male) connectors which should be
securely screwed to the antenna connectors on the rear panel of
the transceiver.
All antenna feedline connections should be
carefully protected from the weather.
4-1
4.6
EXTERNAL SPEAKER WIRING:
An external speaker can be added with or without the internal
speaker remaining active.
Both receiver audio and the internal
speaker are brought out though the interconnect cable. For normal
operation of the internal loudspeaker, the orange wire (INT SPKR)
and blue wire (AF OUT) are connected together.
Connect an
external loudspeaker between the blue wire (AF OUT)and the black
wire (GND). For maximum audio volume, the external speaker should
be a high-efficiency type rated for 4 ohms, 4 watts minimum.
NOTE:
Do not attempt to use the "ship's ground" for audio
circuits. Often, confusing audio problems can be avoided if none
of the external speaker wiring is allowed to contact the ship's
ground.
4.7
NMEA 0183 INPUT PORT WIRING:
A navigation signal, as from a GPS receiver, can be connected to
the SEA 157. The NMEA+ signal lead connects to the yellow wire
and the NMEA- signal lead connects to the green wire.
4-2
5.
THEORY OF OPERATION
Block diagrams, schematic wiring diagrams and printed circuit
board layout drawings are provided in this in Section 7. See the
List Of Figures for aid in locating applicable reference drawings.
5.1
FREQUENCY SYNTHESIZER:
GENERAL: Refer to the functional block and schematic diagrams.
The SEA
157 makes use of a multi-loop synthesizer system to
provide conversion frequencies for the Receiver, and the
Transmitter. The Main Transmitter synthesizer also serves as the
first conversion loop for the Main Receiver and consists of the
voltage controlled oscillator (VCO) Q1, RF buffers/amplifiers Q4
and Q3, synthesizer LSI chip U10 including reference oscillator
crystal Y1, and the loop filter.
VCO: The low-noise VCO is a grounded-gate JFET oscillator
operating in two frequency bands as selected by Q2 and D2. D2 is
"off" for transmit and L5 and L6 set the frequency band to the
155-159 MHz range. D2 is "on" for receive and L6 sets the 176.4185 MHz receiver local oscillator (LO) range. The tuning voltage
from the loop filter is applied to varactors D4 and D5.
The
tuning voltage ranges from 1 to 4 volts with lower voltages
corresponding to higher frequencies. This is because the cathodes
of D4 and D5 are referenced to the +8 volt supply. The entire VCO
and two stage buffer is located on a separate pc board in a
seperately shielded “pocket” in the chassis casting.
VCO RF AMPLIFIERS: Q4 and Q3 amplify the VCO signal up to +10
dBm (10 mW) nominal. The signal is then fed to the receiver PCB
through a 3 dB resistive pad attenuator to the receive mixer U3.
Main board D3 is turned "on" only during transmission to supply
approximately +10 dBm excitation to the transmitter amplifier
chain.
SYNTHESIZER CHIP:
A sample of the amplified VCO signal is
derived from the output of Q3 and fed to the N and A dividers of
U10. The N and A divider modulus is preset by the microcomputer
via the clock, data and enable digital lines. The total frequency
division (N and A) reduces the RF signal down to a 12.5 KHz
comparison frequency at U10's internal phase detector.
For
example, the total division for transmission on 156.800 MHz is the
156,800/12.5 = 12544. For a receive frequency of 156.8 MHz, the
required LO frequency is 156.800 + 21.400 = 178.200 MHz.
The
division factor is 178.200/12.5 = 14,256. The 21.850 MHz master
reference oscillator is divided by a fixed 1748 modulus to produce
the 12.5 KHz reference frequency. The U10 phase detector output
at pin 6 is tri-state and drives the loop filter. A separate lock
detect (LD) output from U10 pin 8 goes mostly low when out of
lock. The LD signal is fed back to the DSP/microcomputer which
disables the transmitter in the unlocked state.
5-1
MASTER REFERENCE OSCILLATOR: The active portion of the master
crystal oscillator is provided by a CMOS gate in U10.
The
oscillator crystal, Y1, is stabilized at 21.850 MHz by C103 and
the positive-temperature-coefficient (PTC) thermistor R73.
The
PTC draws significant current only at temperatures below freezing.
C162 is the transmitter frequency netting adjustment.
LOOP FILTER:
R64 on the main PCB and R3,R4,R13,C2,C4,C5,and C19
on the VCO PCB comprise the loop filter.
5.2
MODULATION CIRCUIT:
TRANSMITTER AUDIO PROCESSING: U6 is an ‘AC97 standard audio
CODEC. Microphone audio is applied to the MIC1 input of U6 and
amplified in an internal 20db gain amplifier before being
digitized and sent to the digital signal processor (DSP), U5. The
DSP then feeds it through a digital filter/limiter process which
filters the transmitter audio with a 3 KHz lowpass filter.
It
then applies a 6db per octave preemphasis, limits the audio in a
low distortion process and finally filters the audio again with a
3 KHz lowpass filter. This method maximizes the average voice
energy within the set deviation limit while minimizing audio
harmonic distortion levels.
DSC DATA: The digital modulation signal is generated internally
in a phase continuous digital sine wave generator.
It is then
feed into the transmitter audio processing (within the DSP) at the
input of the preemphasis.
It is fed in at a level below the
limiting threshold of the audio processing and factory calibrated
for a modulation index of 2.
FREQUENCY DEVIATION CONTROL: The transmitter peak deviation is
controlled digitally by a factory set deviation multiplier
constant which is stored in EEPROM (U4). D2 on the VCO PCB is
switched "on" during receive mode to switch VCO ranges and to
insure that no modulation is applied to the synthesizer during
reception.
5.3
RECEIVER CIRCUITS:
GENERAL: Refer to RF Mainboard Schematic Diagrams, Sheets 1 and
2.
The receiver is a double-conversion superheterodyne with a
total of 10 poles of receiver IF filtering.
RECEIVER RF FRONT END:
RF from the antenna passes through a
highpass filter to the low-noise RF preamplifier Q1. After passing
though U5, the signal passes through the three stage, top coupled
bandpass filter consisting of L1, L2, L3 and their associated
capacitors. The 50 ohm output of the bandpass filter is applied
to double balanced passive diode mixer, U3. The mixer is provided
with +7 dBm LO high-side injection from the VCO buffer through a 3
dB resistive pad consisting of R11 and R12.
The desired mixer
output is the 21.4 MHz first intermediate frequency (IF).
5-2
21.4 MHZ IF AMPLIFIERS: Q2, the first IF amplifier circuit uses
a low noise JFET in the common gate configuration. This circuit
provides a wideband termination for the mixer, U3. L5,C12 andC9
match the four pole 21.4 MHz filter comprised of FL2 and FL1 to
the output impedance of Q2. The input impedance of Q3, together
with L8, C15 and R7 match FL1's output impedance. The second IF
amplifier output is coupled via matching network L4, C17, and C25
to the input of the multipurpose FM receiver chip, U1.
SECOND CONVERSION: The second mixer is of the Gilbert cell type
and is part of the multipurpose FM receiver chip, U1. Mixing the
first IF of 21.4
MHz with the second conversion oscillator
results in a second IF frequency of 455 KHz.
This signal is
filtered by a
six-pole ceramic filter FL3, and then passed on to the limiteramplifier in U1.
The second local oscillator frequency is the
same 21.850 MHz temperature stabilized crystal oscillator as the
master reference.
QUADRATURE DETECTOR: The output of the limiter-amplifier of U1 is
internally fed to the quadrature detector whose phase shift
circuit is provided by quadrature coil L6.
The raw baseband
detected audio emerges from U1 on pin 9 (approximately 0.7 volts
peak-to-peak for a 1 KHz tone, 3 KHz deviation) and is fed to the
CODEC (U6) to be digitized.
DIGITAL DEEMPHASIS/VOLUME CONTROL CIRCUIT: The raw audio from U1
pin 9 is fed to U6 the 16 bit CODEC and is digitally sampled at
42.676 KHz. The digitized audio is then passed to the U5 the DSP
where it split into two signals by a 3 KHz lowpass and a 3 KHz
highpass filter. The highpass filtered portion is fed to the
squelch process described below. The lowpass filtered portion is
multiplied by the digital volume setting value, then the digital
squelch gate and output to the the CODEC, U6. U6 outputs the
receive audio on the line output left pin.
It is then
fed
through R26, R52 and C68 which comprise the deemphasis network. It
is then passed through C2 to U11, the audio output amplifier.
DIGITAL SQUELCH PROCESSING: As described above, the digitized
receiver audio is filtered by a 3 KHz high pass filter and fed to
the digital squelch process.
It is similar to a traditional
noise
activated squelch. The DSP calculates the magnitude of
audio energy above and below 3 KHz and uses this in conjunction
with the squelch threshold setting to intelligently decide whether
to open or close the digital squelch gate.
5.4
TRANSMIT AMPLIFIERS:
GENERAL: Refer to Sheet 2 of the Mainboard Schematic Diagram.
The transmit amplifier chain consists of two discrete RF
amplifiers plus a hybrid RF power amplifier module which contains
two more gain stages. Overall gain is typically 40 or more dB.
5-3
PRE-DRIVERS:
The
approximately
+10
dBm
signal
from
the
synthesizer is first amplified by Q9.
The output of Q9 is
narrowband matched to the low impedance input of Q10 by L6 and
C11.
The output of Q10 (up to 0.6 watts) is matched into the
nominal 50 ohm input impedance of U8.
DC power for Q9 is
controlled by DC switch Q1A.
FINAL AMPLIFIERS:
U8 is a hybrid amplifier containing two gain
stages providing approximately 20 dB overall gain (25 watt mode)
and 25 watts or 1 watt output as required. DC power for the final
stage is obtained directly from the fused 13 volt power source.
5.5
ANTENNA INTERFACE CIRCUITS:
TRANSMIT/RECEIVE SWITCHING:
Antenna changeover between transmit
and receive is accomplished by PIN switches D33 and D35. In the
transmit mode current from 13VTX passed through L7 and L1 to turn
on D33 which passes transmitter RF.
The DC current then passes
through L8, D35 and finally to ground through R3, R122, R123 and
R124. C6, L8 and C123 form a 1/4 wave matching section. When D35
turns on it presents a short to ground through C120 and C121 for
RF. This is reflected as an open circuit at the other end of L8.
This isolates the receiver input from the transmitter RF. The DC
voltage on the cathode end of D35 is also coupled to the source of
the receiver RF amplifier through L9 which biases it off providing
further receiver isolation.
TRANSMIT/RECEIVE FILTERING: A 7-section low-pass filter provides
excellent VHF and UHF harmonic rejection for transmitter harmonics
and receiver images.
5.6 AUTOMATIC RF POWER CONTROL (APC) AND TX LOGIC:
In transmit mode a digital negative feedback control system
continuously monitors and , if necessary, corrects the output
power level at the antenna terminals. C119 samples the RF voltage
at the RF power amplifier output terminal. Diode D34 converts the
RF signal to a DC level proportional to the output power level and
the DC signal is fed to A/D converter U15. The digitized signal
is then applied to the DSC chip and subjected to a power control
routine which, through D/A converter U17, drives DC amplifier (Q5
and Q13) to provide the correct DC supply voltage to Q9 and the
first stage of U16. This is turn creates the proper RF drive to
the final stage. Two reference comparison are used in the control
routine which correspond to 1 watt or 25 watt output levels.
When adjusted according to the alignment instructions, the APC
system will closely maintain the 1 W or 25 W output level (as
selected) over a wide range of power supply voltage and ambient
temperatures. The final RF power amplifier stage cannot produce
more than about 30 watts even in the unlikely event that the
automatic power control system should fail.
5-4
5.7 TX LOGIC DETECTOR: The DC level from rectifier D34 which is
used by the APC circuit above is also used by the DSP to determine
when a power level of at least 1/2 watt is present. If it is, the
DSP then turns on the TX annunciator on the front panel liquid
crystal display.
5.8
POWER and AUDIO CIRCUITS:
All receiver volume, squelch, beep and muting processes are done
within the DSP U5. The processed audio is output through the CODEC
U6 to U11 where it is amplified up to 4 watts maximum power.
Power
volt
fused
13VTX
for most of the internal circuitry is derived from the 13
switched (13VSW) rail. This is derived directly from the
and filtered input voltage from the main power source. The
rail is derived from the 13VSW rail through FET switch Q1A.
Various control switches and regulators are operated from the
+13VSW line. U9, 5 volt regulator operates from this rail. U2, the
3.3 volt regulator operates from 5 volt rail. U7, the 1.8 volt
regulator, operates in turn from the 3.3 volt rail.
U14, the
audio power amplifier also operates from the +13VSW rail.
Both the Receiver and the VCO modules operate from the 13VSW rail
and contain their own regulators; U2 and U1 respectively.
5.9
MICROCOMPUTER CIRCUITRY:
Refer to Sheet 2 of the Main Board schematic diagram.
MICROCOMPUTER: U5 is the digital signal processor chip, a Texas
Instruments TMS320C5402U1. This chip in conjunction with U3, the
FlashROM, U4 the EEPROM, and U6 the audio codec perform all of the
system microcontroller as well as the digital signal processing
functions. U3 contains the system firmware which is loaded into
the internal RAM of U5 at powerup.
As a microcontroller U5
controls all keypad, display memory storage, power management and
other system functions.
U5, in conjunction with U6, the audio
CODEC also performs all digital signal processing functions
including receiver audio processing, filtering, volume control,
beep generation, squelch detection and gating.
All transmitter
audio processing and DSC modem functions are also provided by the
DSP. An NMEA0183 input port is optically coupled to the DSP
through U8. The DSP clock is the 21.850 MHz crystal controlled by
Xtal1, the frequency synthesizer reference.
All baud rates and
timing functions are derived from this oscillator. Non-volatile
memory functions (Scan lists, special channel programs, etc.) are
provided by U4, a 2K EEPROM.
No memory backup batteries are
required.
RESET AND WATCHDOG PROTECTION CIRCUIT: U13 monitors the 3.3 Volt
supply to the DSP. At power on and at any time that the 3.3 volt
supply drops below 3.0 volts, U13 resets the DSP and keeps it
5-5
reset for 200 milliseconds after the voltage returns to normal.
Even momentary brownout conditions will reset the DSP. U13 also
contains a watchdog circuit. Pin 4 of U13 the watchdog input must
be strobed by the processor at least once per second or the DSP
will be reset for 200 milliseconds. This protects the radio in the
unlikely event that the DSP should ever not function properly.
5.10 KEYPAD/KEYPAD LIGHTING:
KEYPAD:
Primary control of the SEA
157 is through the 15 key
keypad.
This keypad is of the conductive rubber type and is
backlighted with internal LEDs.
Both the keyswitch stators and
backlighting components are part of the main PC board. The
individual keys protrude through holes in the front panel bezel.
Backlighting LEDs are configured in four series strings and light
level is controlled by the DSP through pin 2 of U17 the octal DAC.
The DAC output is buffered and amplified by Q7 and Q8. Sixteen
intensity levels are provided.
5.11 DISPLAY/DISPLAY LIGHTING:
DISPLAY: The front panel display is a LED backlighted LCD graphic
module. Various display configurations are provided which permit
the operator to monitor all the various radiotelephone parameters
such as channel number, power level, memory mode, etc.
The
display is controlled by the system DSP through U14, the LCD
controller.
5-6
6.
MAINTENANCE
NOTE:In order to avoid making unnecessary adjustments it is best
to first assess the basic transceiver performance using the steps
outlined in Section 6.3 below.
6.1
GENERAL
BASIC DISASSEMBLY:
NOTE: No disassembly of
calibration of the unit.
1.
the
unit
is
generally
required
for
Prepare a clean surface in the work area.
Static-free
precautions are recommended.
Place radiotelephone on work
surface and remove the eight #4 self tapping screws which
fixes the front panel bezel in place. The front panel bezel
may now be removed, providing access to the interior of the
radiotelephone.
CHASSIS DISASSEMBLY:
The Main PCB is not field removable from the chassis casting.
Contact the factory for return authorization if the main PCB is
damaged.
6.2
RECOMMENDED TEST EQUIPMENT:
1.
13.6 volt, regulated DC power supply with ammeter, rated for
minimum
amps
continuous
duty.
(For
24
volt
radiotelephones,
substitute a 24 volt regulated DC power
supply with ammeter,
rated for minimum 4 amps continuous
duty.)
Calibrated RF wattmeter (Bird Model 43) with 25 watt and 1
watt, 150 MHz elements and a 50 ohm 25 watt load or power
attenuator.
Volt-ohmmeter plus RF probe. eg: Fluke 75 plus Fluke 85RF
probe.
VHF frequency counter, accurate to 10 Hz resolution.
Calibrated frequency deviation meter.
Sinewave audio signal generator.
Calibrated RF signal generator with FM capability, 50 ohm
output
impedance
and
minimum
40
watt
reverse
power
protection.
Audio distortion (SINAD) and audio voltmeter.
Four ohm, four watt resistive load.
Spectrum analyzer, 1 to 1000 MHz, 1 KHz resolution.
Oscilloscope. (50 MHz bandwidth required for receiver first
IF alignment.)
50 ohm, 20 or 30 dB RF power attenuator.
VHF marine FM monitor receiver.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
6-1
6.3
BASIC PERFORMANCE TESTS:
GENERAL:
NOTE:
No disassembly is required to perform basic performance
tests.
The orange audio output wire and the yellow internal
speaker wire must be connected together if internal speaker
operation is desired.
1.
DISPLAY/KEYPAD AND MAIN MEMORY CHECK: When the main power is
turned on, the display will cycle through a self-check
sequence. Following this self-check cycle, the front panel
will revert to the normal RADIO front panel indication.
2.
NON-VOLATILE MEMORY FUNCTION CHECK:
Change the priority
channel to a new channel number.
eg:
Select USA or INT
channel list, then push:
1. 3. ENT, FUNC,and
9 for more
than one second. Unpress 9 and wait one more second. Cycle
radio power OFF then ON. Push 16 twice and verify that the
newly chosen priority channel number (13 in our example) is
displayed. Reset the priority channel to the desired channel
number (USA Channel 16 is recommended).
BASIC TRANSMITTER TESTS:
Set up the equipment as shown in Figure 6.1, "Transmitter Test
Setup".
1.
TRANSMITTER FREQUENCY AND POWER CHECK: Key the transmitter
on channel 16 (156.800 MHz).
The frequency should read
within
+ 780 Hz of the assigned frequency at room
temperature. The wattmeter should read 25 + 2 watts in the
25 watt mode and 0.7 to 1.0 watt in the 1 watt mode. Repeat
this test on channels 01 (156.050 MHz) and 88 (157.425 MHz).
During transmission the TX annunciator should be ON when
either the 1 watt or 25 watt mode is selected.
The DC
current should not exceed 6
amperes in the 25 watt mode (13.6 volt operation), or
2.5 amperes in the 25 watt mode (24 volt operation).
2.
TRANSMITTER PEAK FREQUENCY DEVIATION CHECK:
Key the
microphone on the desired channel and speak in to the
microphone in a normal speaking voice. Verify that the peak
deviation averages more than 4 KHz but does not exceed 5 KHz.
Listen for "clean" sounding audio on a good monitor
receiver.
3.
TRANSMITTER AUTO POWER REDUCTION AND OVERRIDE CHECK: Set the
radiotelephone to channel 13 USA.
Verify that the 1 watt
(1W) annunciator is ON and that the transmitter power is 1
watt unless manual override is used (Holding down any key
while transmitting). Repeat on channel 67 USA.
6-2
BASIC RECEIVER TESTS:
Set up the
Setup".
1.
equipment
as
shown
in
Figure
6.2,
"Receiver
Test
RECEIVER SENSITIVITY AND AUDIO POWER CHECK: Select the USA
channel list.
Set both the receiver and signal generator
frequency to channel 16 (156.800 MHz).
Set the squelch
threshold open.
Apply 1000 Hz sinusoidal, 3 KHz peak
deviation modulation to the signal generator. Start with the
signal generator set to approximately 1 millivolt (-47 dBm)
amplitude.
Set the volume to maximum. The audio voltmeter should read
about 4 volts RMS. Reduce volume to approximately 50% audio
power (2.8 volts RMS on the audio voltmeter).
Reduce signal generator RF amplitude until 12 dB SINAD is
obtained. This should occur at approximately 0.3 microvolts
(-117 dBm) or less.
Repeat check on channel 01A (156.050
MHz) and weather channel 1 (162.550 MHz).
2.
SQUELCH SENSITIVITY CHECK:
Turn off signal generator RF
output.
Increase the squelch threshold until the squelch
just closes. Start with the signal generator RF amplitude at
minimum setting and increase slowly until the squelch just
opens. The signal generator amplitude should not exceed 0.2
microvolts
(-121 dBm).
3.
MODULATION ACCEPTANCE CHECK:
This test checks for proper
alignment of the receiver. Set the signal generator and
receiver to channel 16 (156.800 MHz).
Set the signal
generator modulation to 1 KHz sinusoidal, 3 KHz peak
deviation.
Set the signal generator amplitude to
obtain 12 dB SINAD.
Increase the signal generator
amplitude 6 dB (double the output voltage) and then
increase the peak deviation until the SINAD ratio drops
back to 12 dB SINAD. The final deviation should be 7
KHz or greater.
6.4
TRANSMITTER ALIGNMENT (TUNE UP PROCEDURE):
GENERAL:
Avoid making unnecessary adjustments.
Some or all of
the
following
procedures
should
be
performed
only
after
identifying specific problems during the Basic Performance Tests,
Section 6.3 above.
Transmitter calibration should be performed by qualified service
technicians using the proper test equipment and is only accessible
with specific factory authorization.
To obtain authorization,
contact the factory with the serial number of the unit for an
authorization code.
6-3
Enter the service menu by pressing FUNC-MODE and entering the
service menu activation code.
The various adjustments are
selectable by rotating the the front panel control and pressing
mode when the desired adjustment is displayed. The service menu
allows adjustment of deviation, clock frequency, 1W power level,
25W power level. DSC transmitted high tone, low tone and dotting
pattern are also available for testing purposes. During all of the
service menus PTT is active so that the transmitter can be tested.
Set up equipment as shown in Figure 6.1, "Transmitter Test Setup".
NOTE:
In the event of synthesizer malfunction (unlocked
condition) all display annunciators will flash repeatedly, the
computerized
operating
system
will
fail
to
respond
and
radiotelephone transmit function will be inhibited.
1.
Ensure that a 50 ohm, 25 watt power load or power attenuator
is connected to the antenna terminals.
Ensure that the DC
power source is supplying 13.6 + 0.5 volts to the radio power
lead (Red lead positive, Black lead negative) under 25 watt
transmit conditions.
DO NOT EXCEED 16 VOLTS UNDER ANY
CONDITION. If the transmitter is operated at 25 watts output
for long periods, carefully monitor the temperature of the
chassis for evidence of excessive heating.
2.
TRANSMITTER FREQUENCY:
Place the radio on any desired
channel. Enter the setup mode and select the “CLKTUN” mode.
Push microphone push-to-talk button (PTT) to key transmitter
on any desired channel. Rotate the front panel control until
the transmitter is within 100 Hz of the assigned frequency.
The display will show an adjustment of 0-200 and will
typically be approximately 100.
Press “MODE” to store the
setting.
All other transmitter and receiver channel
frequencies are automatically set by this adjustment.
3.
TRANSMITTER POWER: Set the radiotelephone to channel 14
(156.700 MHz) or any other channel in that range. Select 25
watt output level. Enter the setup mode and select the “25W
ADJ” mode.
(NOTE:
Avoid prolonged transmitter testing on
the emergency channel (16)). Key the transmitter and adjust
the front panel rotary control for exactly 25 watts output.
Press “MODE” to store the value. Use a 25 watt wattmeter
element for maximum accuracy. Select “1W ADJ” in the setup
menu and temporarily adjust the front panel rotary control
for minimum output power.
The TX annunciator on the front
panel display should extinguish, even though the transmitter
is keyed.
Change wattmeter element to a 1 watt unit for
maximum accuracy and adjust for 0.95 watts. Press “MODE” to
store the setting.
Change wattmeter element back to 25
watts. Check channels 01 and 99 for 25 + 2 watts in the 25
watt mode and 0.7 to 1 watt in the 1 watt mode.
The TX
annunciator should now come on in either the 1 watt or 25
watt modes when transmitting.
6-4
5.
TRANSMITTER PEAK FREQUENCY DEVIATION:
NOTE: The DSP transmit audio processing adjusts the audio
gain to a wide range of audio input levels. The deviation
adjustment sets the transmitter deviation level and is not a
microphone gain adjustment.
Once properly factory set it
should not require readjustment for the life of the unit.
Connect an audio sinewave generator to the microphone
terminals. If the audio generator amplitude cannot be
attenuated below 5 millivolts at the microphone terminals,
insert a 10 Kohm or greater resistor between the audio source
and the external microphone terminal.
Set the audio
generator to 1 KHz.
Enter the setup mode and select the
deviation adjustment as described above. Key the transmitter
and watch the deviation meter while varying the audio
generator for maximum deviation. Once the maximum is found,
adjust the deviation adjust the front panel control for 4.8
KHz peak deviation.
The LCD display will show a deviation
setting between 0 and 200 and should typically be about 100.
Press the mode key to store the deviation setting.
The
resulting audio level at the external microphone terminals
should be approximately 40 millivolts peak-to-peak or 14 mv
RMS. Now set the generator to 2500 Hz and verify that the
deviation does not exceed 5 KHz peak under any amplitude
condition up to at least 400 millivots RMS at the microphone
terminals.
Remove the series dropping resistor from the
audio generator path if necessary to achieve this audio drive
level.
Disconnect the audio generator.
Key the transmitter and
speak loudly into the microphone to verify that the frequency
deviation does not exceed 5 KHz. Now speak at normal volume
into the microphone and verify that the deviation averages 4
KHz or more. NOTE: The particular damping characteristics
of the deviation meter must be taken into account since most
deviation meters will overshoot on voice peaks. Listen for
"clean" audio on a good monitor receiver.
6.
SPECTRAL PURITY:
Connect a 1000 MHz spectrum analyzer
through the power attenuator and verify that harmonics or
spurious signals do not exceed -60 db with respect to 25
watts (-16 dbm) during both modulated and unmodulated
conditions.
Change to 1 watt output power mode and verify
that harmonics or spurs do not exceed -46 dbm with respect to
1 watt (-16dbm) during both modulated and unmodulated
conditions. CAUTION! Spectrum analyzer overload will lead to
erroneous results, especially at the transmitter harmonic
frequencies. To avoid overload, 60 or 70 minimum attenuation
is usually required between the transmitter output terminals
and the first mixer of the spectrum analyzer, regardless of
the center frequency and span being viewed.
6-5
6.5
RECEIVER ALIGNMENT:
GENERAL: The receiver is
serviceable adjustments.
problems
are
identified,
authorization.
factory aligned and has no field
If specific receiver performance
contact
the
factory
for
return
6-6

---

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Title                           : April 5, 2000 FIRST DRAFT
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