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

SEA Inc of Delaware VHF Marine Radiotelephone/DSC Controller April 5 2000 FIRST DRAFT

ta8man users manual theory of operation and tuneup procedures

April 5, 2000 FIRST DRAFT4/10/2000 1st REVSEA INC OF DELAWAREPRELIMINARY MAINTENANCE MANUALVHF FM RADIOTELEPHONE/DSC CONTROLLERMODEL SEA 157(c) Copyright 2000SEA, Inc.All rights reserved.SEA, Inc.7030 220th St. S.W.Mountlake Terrace, Washington 98043(425) 771-2182FAX: (425) 771-2650
**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 PAGE1. INTRODUCTION............................................1-12. SEA 157 SPECIFICATIONS..................................2-12.1 General............................................2-12.2 Transmitter........................................2-12.3 Receiver...........................................2-22.4 Mechanical.........................................2-32.5 DSC controller.....................................2-43. OPERATING THE SEA157....................................3-13.1 Front panel controls...............................3-13.2 Display............................................3-13.3 Push to talk.......................................3-13.4 Radiotelephone operating system functions..........3-23.5 Digital selective calling operating system.........3-63.6 Receiving a call...................................3-83.7 Inputting position data and time...................3-83.8 Programming the DSC ID (MMSI)......................3-93.9 Programming the DSC Address Book...................3-93.10 Using test, calibration and diagnostic utilities...3-103.11 Master USA frequency list..........................3-113.12 International Channel list.........................3-123.13 Weather Channel list...............................3-124. INSTALLATION............................................4-14.1 Preliminary check..................................4-14.2 Shelf or overhead mounting.........................4-14.3 Bulkhead mounting..................................4-14.4 Power supply wiring................................4-14.5 Antenna wiring.....................................4-14.6 External speaker wiring............................4-24-7 NMEA 0183 input wiring.............................4-25. THEORY OF OPERATION.....................................5-15.1 Frequency synthesizer..............................5-15.2 Modulation circuit.................................5-25.3 Receiver circuits..................................5-25.4 Transmit amplifiers................................5-35.5 Antenna interface circuits.........................5-45.6 Automatic RF power control and TX logic............5-45.7 TX Logic detector..................................5-55.8 Power and Audio circuits...........................5-55.9 Microcomputer circuitry............................5-55.10 Keypad/keypad lighting.............................5-65.11 Display/display lighting...........................5-6
6. MAINTENANCE.............................................6-16.1 General............................................6-16.2 Recommended test equipment.........................6-16.3 Basic performance tests............................6-26.4 Transmitter alignment..............................6-46.5 Receiver alignment.................................6-57. SCHEMATICS..............................................7-1
LIST OF FIGURESFIG. ___________________DESCRIPTION___________________ Page2.1 Front view of SEA 157.........................2-52.2 Rear view of SEA 157..........................2-64.1 Outline Dimensions of SEA 157.................4-24.2 Flush Mount Kit Drill Template for SEA 157....4-56.1 Transmitter test setup........................6-106.2 Receiver test setup...........................6-117.1 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 INTRODUCTIONThis SEA 157 Service Manual provides detailed technicalinformation for use by installation and service technicians.General operating instructions and installation drilltemplates 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 wemay better serve our customers. SEA reserves the right tomake changes to SEA 157 specifications, hardware, softwareor documentation at any time without notice.SEA's Marine Service Department is always available toprovide additional help with technical difficulties.Please call SEA's Service Department to obtain a ReturnAuthorization Number (RA#) before shipping equipment to SEA.Service parts are available through SEA's MarineSales/Service Departments. Please order parts using SEA partnumbers found in Section 8.1-1
2 SEA 157 SPECIFICATIONS:2.1 GENERALFREQUENCY RANGE: TX 155-159 MHzUS TX 156.0-157.5 MHzRX 155-164 MHzFREQUENCY RESOLUTION: 25 KHzCHANNELS: All US, Canadian, Int'lplus 10 WXPOWER REQUIREMENT: Voltage, 12 V +30, -10%NOTE: Basic radio Circuitry 13.6 volts nominal neg-operates at 12 volts. ative ground.CURRENT: (12 Volt operation) Max TX: 5.5 amps (25W)1.0 amps (1W)RX (STBY) 0.4 ampRX (Max Audio 1 ampFUSES: (12 Volt operation) 7.5 amp, external line2.2 TRANSMITTEREMISSION: 16K0G3E (Voice)13K5G2B (DSC)POWER OUTPUT: 25W, 1W into 50 ohmsSPURIOUS EMISSIONS: -80 dB or betterSPURIOUS RADIATION: Complies with FCC 80.211(f)AUDIO HARMONIC DISTORTION: 10% max. (EIA)AUDIO FREQUENCY RESPONSE: +1,-3 dB of +6 dB/octavepreemphasis 300-3000 HzHUM AND NOISE: 50 dB (EIA)FREQUENCY DEVIATION: 5 KHz max. peakCARRIER FREQUENCY STABILITY: +5 ppm, -30 to +60 C(FCC, EIA)TRANSMITTER ATTACK TIME: < 100 milliseconds (EIA)2-1
2.3 RECEIVERFREQUENCY RANGE: Simplex 155-159 MHzSemi-duplex 159-164 MHzINTERMEDIATE FREQUENCIES: 21.4 MHz, 450 KHzSENSITIVITY: < 0.3 uv for 12 dB SINADAUDIO FREQUENCY RESPONSE: Within +1,-3 dB of 6 dB per octave deemphasis from 300-3000 Hz (EIA)AUDIO OUTPUT: 4 W at less than 10%distortion into external4 ohm load. 2 W internalHUM 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 EIASQUELCH SENSITIVITY: Threshold: .2 uv max. (EIA)Tight: max 10 dB abovereference sensitivity (EIA)RECEIVER ATTACK TIME: Less than 100 msec (EIA)RECEIVER CLOSING TIME: 100 msec typical250 msec maxSCAN RATE: Max 10 channels/secondMODULATION ACCEPTANCE: 6 KHz minimum (EIA)7 KHz typical2-2
2.4 MECHANICALDIMENSIONS: (HEIGHT-WIDTH-DEPTH)In: 3.6 x 9.6 x 3.1mm: 91 x 244 x 79WEIGHT: Lbs: 3.0Kgs: 1.42-3
2.6 SEA 157 VHF DIGITAL SELECTIVE CALLING CONTROLLERThe VHF Digital Selective Calling Controllerincorporated into the SEA 157 VHF Radiotelephone hasbeen designed to comply with all FCC regulations givenin 47 CFR 80.225. This encompasses compliance with thefollowing documents which are included for reference:80.225(a) ITU-R Recommendation M.493-9 Class D80.225(a) RTCM Paper 56-95/SC101-STD2-4
3. OPERATING THE SEA 1573.1 FRONT PANEL CONTROLSFigure 2.1 illustrates the front panel of the SEA 157. Thefunctions of the individual controls and indicators are listedbelow.3.1.1 ROTARY CONTROLSThe rotary control of the SEA 157 is used for several radiofunctions. It can be used to adjust the channel, volume, squelchand backlighting from the normal radio operating mode. In othermodes, such as editing the DSC address list, it is used to selectcharacters of the alphabet and in the setup mode it is used toselect from a list of setup options.The user can set the default mode for the rotary control using thesetup menu. The rotary control will return to the default state 5seconds (user selectable) after the last adjustment is made.Squelch mode adds 5 seconds to this timeout to allow for squelchon/off time while adjusting the level.3.1.2 KEYPADA 15 key backlighted keypad is provided which, together with theLCD graphics display, provides an operating system which permitsthe operator to control both the radiotelephone and digitalselective calling (DSC) features of the SEA 157.3.2 DISPLAYThe LCD display used in the SEA 157 is a LCD display with a 14segment 8 character display, 7 segment 3 digit display and 17annunciator flags. The display is backlighted and is usedinteractively with the keypad to provide an effective operatorinterface to the radiotelephone/DSC functions of the SEA 157.3.3 PUSH TO TALKThe radio is put into transmit mode by pressing the microphonepush to talk key. It remains in transmit mode until the push totalk switch is released or until the internal 5 minute timerexpires. The TX annunciator is displayed during transmit. Notethat the internal DSC controller can also initiate transmissionsindependent of the push to talk switch on the microphone.3-1
3.4 RADIOTELEPHONE OPERATING SYSTEM FUNCTIONS3.4.1 CHANNEL SELECTIONThe rotary control is used to select the channels. Push the MODEkey until the CH flag is on, then use the rotary control to selectthe desired channel. This operates within the current channel listand wraps around at both ends of the list. eg. from channel 88A tochannel 1 when moving up through the list.The 8 digit display shows the channel name while in this mode. Thedisplay reverts to the current Lat/Long after 5 seconds of noactivity.The numerical keys can also be used to select a channel directly. The radio supports the standard 2 digit VHF channel list. Toenter a channel press the channel number with leading digits toswitch to the channel immediately. If a single digit is pressedand you delay for 5 seconds the radio will switch to that singledigit channel. For example, to go to channel 23 press 2,3 toswitch to the channel immediately. Press 0,5 to go to channel 5immediately. Press 6 and pause for 5 seconds and the radio willswitch to channel 6.In the Weather list the operation is similar to this, if the 2through 9 keys are pressed in WX mode the channel is selectedimmediately, because there are only 10 weather channels available.If 0 is pressed then the channel number from 1 to 9 is waited forwith the first digit blinking. If 1 is pressed it waits for the 0if you want to go to channel 10 or times out after 5 seconds andgoes to channel 1.3.4.2 ON-OFF/VOLUME CONTROLThe rotary control is used for this function. Push the MODE keyuntil the VOL flag is on, then use the rotary control to set thedesired volume level. The squelch is temporarily turned off whilethe volume level is being adjusted so that the volume level can bemonitored. The SQL setting is returned to the user selected state5 seconds after the last rotary control adjustment.3.4.3 SQUELCH CONTROLPush the MODE key until the SQ flag is on, then use the rotarycontrol to adjust the squelch level as desired. The squelch willbe temporarily activated so that you can listen to the effect thecurrent setting will have. The squelch is returned to the userselected state 10 seconds after the last adjustment.Pressing FUNC-2 will toggle the squelch on and off, as indicatedby the SQL flag on the display.3-2
3.4.4 CHANNEL LIST SELECTIONPressing FUNC-8 will toggle the radio between the USA and INTchannel lists. The radio will go to the last used channel in theselected list. If it is pressed while in the Weather list it willreturn to the previous list.Pressing FUNC-3 will switch the radio to the weather list,remembering the current list and channel. Pressing FUNC-3 againwill return the radio to the previous channel list and channel.3.4.5 EMERGENCY CHANNEL SELECTIONPushing 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 itwhile in the Weather list it will go to CH 16 in the last usedlist.3.4.6 TRANSMITTER POWER CONTROLPressing FUNC-1 toggles the transmitter power level on channelsthat allow 25W transmission. On channels that only allow 1W thisfunction does nothing. When transmitting on a 1W only channel theFUNC key can be held down while transmitting to temporarily switchto 25W. The display will show the 1W flag when in the 1W mode andthe 1W flag will be off when 25W is active.3.4.7 DUAL WATCHThe SEA 157 has two watch modes available. Dual watch is initiatedby pressing FUNC-6 briefly while on the primary channel you wantto monitor. The 8 character display will say 'DUAL 16' and channel16 will be checked every 2 seconds while there is no activity oneither channel. If there is activity on the primary channel or onchannel 16 the radio will hold on that channel until there is noactivity for [hangtime] seconds. This behavior can be changed sothat channel 16 always has priority by using the Dual Watch setupmenu option.The channel number display will indicate which channel it isoperating on. Pressing PTT will exit dual watch and switch to thecurrent channel.If Dual Watch is selected while on channel 16 it will not start adual watch.The Triple Watch function is started by pressing FUNC-6 for longerthan 1 second on the primary channel that you want to monitor. Thedisplay will show 'TRIPL 16' and will check channel 16 and thePriority channel every 2 seconds. By default channel 16 haspriority, but this behavior can be changed using the Triple Watchsetup menu option.3-3
3.4.8 SEEKThe Seek mode scans all channels in the selected list (USA/INT/WX)and is started by pressing FUNC-5 for more than 1 second. Thedisplay will show 'SEEKING' and the radio will scan all thechannels in the current list.A Priority seek is started by first selecting the PRI channelusing FUNC-9 and then starting a Seek. The PRI channel will bechecked in-between every channel.Starting a seek after pressing CH16 will seek all channels andcheck channel 16 in-between each channel.3.4.9 SCANThe Scan function is started by briefly pressing the FUNC-5. Thedisplay will show 'SCANNING' and the radio will scan the channelsthat are members of the Scan List (indicated by the MEM flag). Itwill scan the channels, and hold on an open channel for the user selectable hangtime after the channel becomes inactive. Channel 16is always included in the scan list, no matter what its MEM liststate.Only the memorized channels in the current list will be scanned.A Priority scan mode is started by first selecting the PRI channelusing FUNC-9 and then pressing FUNC-5. The PRI channel will thenbe checked in between every channel in the scan list.Starting a scan after pressing CH16 will scan channel 16 inbetween every channel in the scan list.3.4.10 PRIORITY SCANIf 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 PROGRAMMINGThe FUNC-4 MEM function adds or removes the current channel fromthe scan list. The MEM flag will be on if the current channel isincluded in the scan list. The memorized channels can be scannedby using the FUNC-5 scan function.3.4.12 PRIORITY CHANNEL PROGRAMMINGBriefly pressing FUNC-9 switches the radio to the programmedpriority calling channel. Pressing FUNC-9 for more than 1 secondwill set the current channel as the priority channel, as indicatedby the PRI flag being on when then channel is selected. Thefactory default for the PRI channel is channel 9, in the USAchannel list.The priority channel is also used by the Triple Watch mode and thePriority scan and seek modes.3-4
3.4.13 SEARCH MODE PROGRAMMINGEnter the setup menu using FUNC-MODE and then select the ‘SEARCH’function with the rotary control. Press MODE to adjust the searchmode operation. Use the rotary control to select from 2 styles ofsearch 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 thencontinue the search.3.4.16 PRIORITY/DUAL SCAN MODE PROGRAMMINGEnter the setup menu using FUNC-MODE and then select the‘DUALWTCH’ function with the rotary control. Press MODE to adjustthe Dual Watch mode operation. Use the rotary control to selectfrom 2 styles of dual watch:[ACt]1 - Stop on first active channel[C16]2 - CH 16 always has priority, and is checked even when thereis activity on other channels3.4.17 SCAN HANG TIME PROGRAMMINGEnter the setup menu using FUNC-MODE and then select the‘HANGTIME’ function with the rotary control. Press MODE to adjustthe hangtime. Use the rotary control to select the amount of timefor the radio to stay on a channel after the squelch closes, in0.5 second increments from 0 to 20 on the display (0 to 10seconds).3.4.18 ADJUSTING THE BACKLIGHTING LEVELPush the MODE key until the DIM flag is on, then use the rotarycontrol to adjust the brightness level. The display will show thebrightness level.3.4.19 KEY BEEP CONTROLEnter the setup menu using FUNC-MODE and then select the ‘BEEPLVL’ function with the rotary control. Press MODE to adjust thebeep level. Use the rotary control to select the beep volumelevel, 0-15. The radio will emit a short test beep for every turnof the rotary control.3.4.21 MODIFYING CHANNEL NAMESSelect the channel to be edited using the rotary control or directchannel entry. The channel’s current ASCII tag will be displayedfor 3 seconds. Select the channel editing function by pressingFUNC-MODE and selecting the ‘CHANNAME’ option. Press MODE to editthe ASCII tag for the channel. The display shows the current radio3-5
channel with the first digit of the channel’s ASCII tag blinking.Use the rotary control to select the character and press MODE tomove to the next digit. Pressing FUNC will move to the previousdigit, and pressing any other key will exit from the channel editwithout saving changes. Once the final digit has been edited andMODE key pressed the new channel tag will be saved to non-volatilememory. A character set of upper case A-Z, numbers 0-9 and a spaceare available for the selection.Pressing CH16 or DIST in this mode will immediately exit theediting mode and activate their respective functions.3.5 DIGITAL SELECTIVE CALLING OPERATING SYSTEM3.5.1 DISTRESS CALLINGPressing the DIST key for 3 seconds will cause the radio to enterthe DSC distress mode. The radio will switch to channel 70 and thedisplay will show 'DISTRESS' and ‘PRESSPTT’ while waiting for PTTto be pressed, if the current position is known (a GPS or otherdevice must be attached to the NMEA input). The radio is now readyto transmit the distress call by pressing PTT. Press PTT to sendthe distress call - the radio will wait for channel 70 to beclear, displaying 'BUSY' while it is waiting, and then transmitthe distress call. The radio will then wait for an acknowledge andthe display will alternate between ‘DISTRESS’ and ‘WAIT ACK’. Ifnone is received within 3.5 to 4.5 minutes then the distress callwill automatically repeat until an acknowledge is received.Pressing PTT will resend the distress call immediately. When anacknowledgement is received then the radio beeps and switches tochannel 16. The display switches to 'DIST ACK' and the radioenters 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 thenumeric keys to select the correct location, using MODE to move tothe next digit. When the Longitude is entered the E/W digit willflash and the rotary control will select E or W. When MODE ispressed after the E/W is selected the display changes to ' -- --N'with the first digit blinking. Enter the Latitude, using therotary control to select the N/S and press MODE to continue. Youwill then be prompted to enter the time when the position wasvalid, the display will show ‘00-00‘ with the first digitblinking. 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 anemergency by holding down the DIST key for 5 seconds. The displaywill show ‘DISTRESS’ and ‘PRESSPTT’ while waiting for PTT. Pleasenote that the DSC call will indicate that the position is unknown.3-6
3.5.2 DSC CALLThe SEA 157 also supports All ships and Individual call DSCtransmissions. Select a simplex channel to use for voicecommunications after the call and press FUNC-0 to initiate a DSCcall. The radio will switch to channel 70, the DSC callingchannel, 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 andthe radio will beep twice to indicate an error. You must firstselect a channel to use for voice communications after the DSCcall is acknowledged and then press FUNC-0 to select the DSCstation to call.3.5.2.1 ROUTINE INDIVIDUAL DSC CALLSelect the DSC calling mode using FUNC-0, and then use the rotarycontrol to select the DSC call to make from the list of DSCaddresses previously entered using the DSC Address programmingmode from the SETUP menu. Once the desired DSC call is selectedpush the PTT button to transmit the call. The radio checks for aclear channel and transmits the call. If the channel is busy theradio will alternate between displaying 'BUSY' and ‘DSC CALL’while it waits for the channel to clear. Once the channel is clearthe call will be transmitted automatically.The DSC mode can be aborted at any time by pressing the MODE keyor it will revert to normal radio operation if there is no useractivity for 30 seconds.When an individual call is sent the unit will wait for anacknowledge to be received before switching to the selectedchannel. While waiting for the acknowledge the radio willalternate between showing ‘DSC CALL’ and ‘WAIT ACK’, and the callcan be resent immediately by pressing PTT. Once the acknowledge isreceived the radio will switch to the selected voice channel andthe display will show ‘ABLE’ or ‘UNABLE’, depending on theresponse received, until the used takes action such as keying theradio or changing channels.3.5.2.4 ALL SHIPS CALLSSelect the DSC calling mode using FUNC-0 and then use the rotarycontrol to select ‘ALL SHIP’ from the menu. When an All Ships callis made the radio does not wait for an acknowledge, it switches tothe selected voice communications channel immediately after thecall is sent.3-7
3.6 RECEIVING A CALLTo receive DSC calls the radio must be monitoring channel 70. Whena DSC call is received the radio will beep in a unique fashion toindicate either a Distress call or a normal call.When a distress or distress relay call is received the radio willautomatically switch to high power on channel 16 and the displaywill show 'DISTRESS' or 'DIST RLY'. An alarm tone will sound untilthe CH16 key is pressed to silence it, or 2 minutes have passed.When an all ships or geographic call is received the radio willbeep and switch to the voice channel specified by the callingstation. The display will show 'ALL SHIP' or 'GEO CALL' while onthe selected channel. The display will revert to its normaloperating mode when the channel selector is changed or a key ispressed.When an individual call is received additional action may be takenautomatically, depending on the setting of the DSC Receive modesetup menu:If an automatic reply has been selected in the Setup menu it willbe sent and the radio will switch to the voice channel selected bythe calling station. The display will alternate between 'INDIVID'and the name or DSC ID of the caller until the user selectsanother channel.If the manual reply mode is selected then the radio will display'ABLE' and beep once per second. You can select 'UNABLE' using therotary control. Pressing PTT will transmit the acknowledgement andthe radio will then switch to the channel selected by the callingstation if ‘ABLE’ was sent. If ‘UNABLE’ was sent it will stay onchannel 70.If the Manual+Timeout DSC Receive mode is selected then the radiowill display 'UNABLE ' and beep until 'ABLE ' is selected usingthe rotary control and PTT is pressed. If 4.5 minutes pass withoutthe user selecting 'ABLE' then the radio will transmit the unableto comply message and remain on channel 70.While on the selected voice channel the display will alternatebetween 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 TIMEPress FUNC-MODE and use the rotary control to select the ‘SET LOC’menu. Press MODE and the display will show '--- --W' with thefirst digit blinking. Use the rotary control or the numeric keysto enter the correct longitude, using MODE to move to the nextdigit. When longitude is entered the E/W digit will flash and the3-8
rotary control will select E or W. When MODE is pressed after theE/W is selected the display changes to ' -- --N' with the firstdigit blinking. Enter the Latitude, using the rotary control toselect the N/S and press MODE to continue. You will then beprompted to enter the time that the position was valid at, thedisplay will show ‘00-00‘ with the first digit blinking. Afterentering the time the radio will return to receive operation onthe current channel.If a GPS receiver is attached the display will show the last validlocation and time. If new valid data is received from the GPS itwill take precedence over what is entered above. This functionshould only be used when there is no GPS attached, or when the GPSdata 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 withthe first digit blinking if you are allowed to change the DSC ID.The DSC ID is allowed to be changed twice after factoryinitialization. If the ID can be changed then the first digit willblink and the rotary control should be used to select the digits,using MODE to move to the next digit. Pressing CH16 or DIST willexit the setup mode immediately with no changes being saved.3.9 PROGRAMMING THE DSC ADDRESS BOOKPress FUNC-MODE and use the rotary control to select ‘ADDRESS’from the menu. Press MODE and the 3 digit display shows an 'A' inthe left digit and the address bin number 1-10 in the right 2digits. The 8 character display shows the current ASCII name forthe selected bin or ‘BLANK’ for a blank entry. Use the rotarycontrol to select the address bin to enter or change and pressMODE again. The 8 digit and 3 digit display will show the DSC IDand the first digit will blink. Use the rotary control to selectthe digits, pressing MODE to move to the next digit until alldigits have been entered. FUNC will move the cursor back 1 digit.Once all the digits have been entered the display will then showthe name of the address bin, with the first digit blinking. Usethe rotary control to select the characters, pressing MODE to moveto the next digit and FUNC to move to the previous digit. PressingCH16 will abort the edit and go to Channel 16.When the DSC ID and name have been entered the radio returns tothe Address list review mode to allow multiple addresses to beeasily added to the radio. You can exit from this mode by pressingCH16.3-9
3.10 USING TEST, CALIBRATION AND DIAGNOSTIC UTILITIESEnter the service menu by pressing FUNC-MODE and entering theservice menu activation code (contact the factory with the radio’sserial 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 thetransmitter can be tested.3.10.1 CLOCK TUNINGSelect 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 storethe new setting and exit the adjustment mode.3.10.2 POWER LEVEL ADJUSTMENTSelect the ‘1W ADJ’ or the ‘25W ADJ’ mode from the service menu.Press MODE to enter the adjustment menu. The 3 digit display willshow the current power level control setting and the right 3digits of the 8 character display will show the forward powerreading. Pressing PTT will transmit and the ALC will adjust thepower level to be equal to the setting selected. Press MODE tostore the setting to non-volatile memory and exit the servicemenu.3.10.3 DSC TONE TRANSMITSelect 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 dotpattern. Press MODE to exit the service menu.3-10
3.11 USA CHANNEL LISTINGChannel S/D SHIP TX Ch. Designation 01 D 156.050 01A S 156.050 Port Operations, Commercial 02 --- 156.100 RX Only 03A S 156.150 04A--- 156.200 RX Only 05A S 156.250 (VTS), U.S. Only, Port Ops 06 S 156.300 Intership Safety 07A S 156.350 Commercial 08 S 156.400 Commercial, Non-Commercial 09 S 156.450 Commercial, Non-Commercial 10 S 156.500 Commercial 11 S 156.550 (VTS), Commercial 12 S 156.600 (VTS), Port Ops 13 S 156.650 Bridge-to-Bridge, Navigational(Manual override to 25 watts) 14 S 156.700 (VTS), Port Ops 15 S 156.750 RX only (Coast to Ship Environmental) 16 S 156.800 DISTRESS AND CALLING 17 S 156.850 Maritime Control 18A S 156.900 Commercial 19A S 156.950 Commercial 20 D 157.000 Port Ops 20A S 157.000 Port Ops, Intership 21A* S 157.050 U.S. Govt ONLY (USCG) 22A S 157.100 U.S. Coast Guard 23 D 157.150 Public Correspondence 23A* S 157.150 U.S. Govt ONLY 24 D 157.200 Public Correspondence 25 D 157.250 Public Correspondence 26 D 157.300 Public Correspondence 27 D 157.350 Public Correspondence 28 D 157.400 Public CorrespondenceChannel S/D SHIP TX Ch. Designation 60 --- 156.025 RX Only 61A* S 156.075 Public Correspondence 62A --- 156.125 RX Only 63A S 156.175 Port Ops, Commercial 64 S 156.225 Public Correspondence 65A S 156.275 Port Ops 66A S 156.325 U.S. Only, Port Ops 67 S 156.375 Commercial, "Bridge-to-Bridge" Nav(Manual override to 25 watts) 68 S 156.425 Non-Commercial 69 S 156.475 Non-Commercial 70 S 156.525 Digital Selective Calling (DSC) 71 S 156.575 Non-Commercial3-11
72 S 156.625 Non-Commercial 73 S 156.675 Port Ops 74 S 156.725 Port Ops 77 S 156.875 Port Ops, Intership Only(Manual override to 25 watts) 78A S 156.925 Non-Commercial 79A S 156.975 Commercial 80A S 157.025 Commercical 81A* S 157.075 U.S. Govt ONLY 82A* S 157.125 U.S. Govt ONLY 83A* S 157.175 U.S. Govt ONLY 84 D 157.225 Public Correspondence 85 D 157.275 Public Correspondence 86 D 157.325 Public Correspondence 87 D 157.375 Public Correspondence 88 D 157.425 Public Correspondence 88A S 157.425 Commercial Intership3-12
3.20 International Channel listingNOTE: Amended International Channel List is identicalto the SEA 157 International Channel List with thefollowing exceptions:Channel S/D SHIP TX Ch. Designation 01 D 156.050 Canada Public Correspondence ................................................................. 02 D 156.100 Canada Public Correspondence ................................................................. 04A S 156.200 Canada Public Correspondence ................................................................. 60 D 156.025 Canada Public Correspondence ................................................................. 62A S 156.125 Canada Public Correspondence ................................................................3.21 Weather Channel listingBin Smpx TX 25W SHIPRX SHIPTX Tag1 D N 162.550 - WEATHER 12 D N 162.400 - WEATHER 23 D N 163.475 - WEATHER 34 D N 161.275 - WEATHER 45 D N 161.650 - WEATHER 56 D N 162.775 - WEATHER 67 D N 162.425 - WEATHER 78 D N 162.450 - WEATHER 89 D N 162.500 - WEATHER 910 D N 162.525 - WEATHR 103-13
4. INSTALLATION4.1 PRELIMINARY CHECK:Prior to installation, the transmit frequency, peak frequencydeviation and RF power output level should be checked on acalibrated FM service monitor or equivalent equipment. SeeSection 6 of this manual for more detailed procedures.4.2 SHELF OR OVERHEAD MOUNTING:See Figure 4.1 for dimension drawings of SEA 157.4.3 BULKHEAD MOUNTING:A special bulkhead mounting bracket (SEA P/N KIT-0157-30) isavailable from SEA which permits through-bulkhead mounting of theSEA 157. The required depth behind the bulkhead is approximately11.5 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 forproper operation. Direct connection to the battery or powersupply is recommended. Connect the RED positive (+) power lead tothe positive supply rail. The BLACK negative (-) power leadconnects to the negative supply rail. NOTE: The chassis of theSEA 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 theradiotelephone, the fuse will blow. It is also likely that thereverse-polarity protection diode, D2, which is near the powerlead connections on the main circuit board will also be damaged. Application of voltages greater than the maximum rated voltagewill produce the same result. (Refer service of this equipment toa qualified technician.)4.5 ANTENNA WIRING:Use only the best available antennas, 50 ohm coaxial antennafeedline cable and connectors. The antennas must be verticallypolarized. The antenna cables should be terminated with properlyinstalled PL-259 (Type UHF male) connectors which should besecurely screwed to the antenna connectors on the rear panel ofthe transceiver. All antenna feedline connections should becarefully protected from the weather. 4-1
4.6 EXTERNAL SPEAKER WIRING:An external speaker can be added with or without the internalspeaker remaining active. Both receiver audio and the internalspeaker are brought out though the interconnect cable. For normaloperation of the internal loudspeaker, the orange wire (INT SPKR)and blue wire (AF OUT) are connected together. Connect anexternal loudspeaker between the blue wire (AF OUT)and the blackwire (GND). For maximum audio volume, the external speaker shouldbe a high-efficiency type rated for 4 ohms, 4 watts minimum. NOTE: Do not attempt to use the "ship's ground" for audiocircuits. Often, confusing audio problems can be avoided if noneof the external speaker wiring is allowed to contact the ship'sground.4.7 NMEA 0183 INPUT PORT WIRING:A navigation signal, as from a GPS receiver, can be connected tothe SEA 157. The NMEA+ signal lead connects to the yellow wireand the NMEA- signal lead connects to the green wire.4-2
5. THEORY OF OPERATIONBlock diagrams, schematic wiring diagrams and printed circuitboard layout drawings are provided in this in Section 7. See theList 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 toprovide conversion frequencies for the Receiver, and theTransmitter. The Main Transmitter synthesizer also serves as thefirst conversion loop for the Main Receiver and consists of thevoltage controlled oscillator (VCO) Q1, RF buffers/amplifiers Q4and Q3, synthesizer LSI chip U10 including reference oscillatorcrystal Y1, and the loop filter.VCO: The low-noise VCO is a grounded-gate JFET oscillatoroperating in two frequency bands as selected by Q2 and D2. D2 is"off" for transmit and L5 and L6 set the frequency band to the155-159 MHz range. D2 is "on" for receive and L6 sets the 176.4-185 MHz receiver local oscillator (LO) range. The tuning voltagefrom the loop filter is applied to varactors D4 and D5. Thetuning voltage ranges from 1 to 4 volts with lower voltagescorresponding to higher frequencies. This is because the cathodesof D4 and D5 are referenced to the +8 volt supply. The entire VCOand two stage buffer is located on a separate pc board in aseperately shielded “pocket” in the chassis casting.VCO RF AMPLIFIERS: Q4 and Q3 amplify the VCO signal up to +10dBm (10 mW) nominal. The signal is then fed to the receiver PCBthrough a 3 dB resistive pad attenuator to the receive mixer U3. Main board D3 is turned "on" only during transmission to supplyapproximately +10 dBm excitation to the transmitter amplifierchain.SYNTHESIZER CHIP: A sample of the amplified VCO signal isderived from the output of Q3 and fed to the N and A dividers ofU10. The N and A divider modulus is preset by the microcomputervia the clock, data and enable digital lines. The total frequencydivision (N and A) reduces the RF signal down to a 12.5 KHzcomparison frequency at U10's internal phase detector. Forexample, the total division for transmission on 156.800 MHz is the156,800/12.5 = 12544. For a receive frequency of 156.8 MHz, therequired LO frequency is 156.800 + 21.400 = 178.200 MHz. Thedivision factor is 178.200/12.5 = 14,256. The 21.850 MHz masterreference oscillator is divided by a fixed 1748 modulus to producethe 12.5 KHz reference frequency. The U10 phase detector outputat pin 6 is tri-state and drives the loop filter. A separate lockdetect (LD) output from U10 pin 8 goes mostly low when out oflock. The LD signal is fed back to the DSP/microcomputer whichdisables the transmitter in the unlocked state.5-1
MASTER REFERENCE OSCILLATOR: The active portion of the mastercrystal oscillator is provided by a CMOS gate in U10. Theoscillator crystal, Y1, is stabilized at 21.850 MHz by C103 andthe positive-temperature-coefficient (PTC) thermistor R73. ThePTC 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 C19on the VCO PCB comprise the loop filter.5.2 MODULATION CIRCUIT:TRANSMITTER AUDIO PROCESSING: U6 is an ‘AC97 standard audioCODEC. Microphone audio is applied to the MIC1 input of U6 andamplified in an internal 20db gain amplifier before beingdigitized and sent to the digital signal processor (DSP), U5. TheDSP then feeds it through a digital filter/limiter process whichfilters the transmitter audio with a 3 KHz lowpass filter. Itthen applies a 6db per octave preemphasis, limits the audio in alow distortion process and finally filters the audio again with a3 KHz lowpass filter. This method maximizes the average voiceenergy within the set deviation limit while minimizing audioharmonic distortion levels.DSC DATA: The digital modulation signal is generated internallyin a phase continuous digital sine wave generator. It is thenfeed into the transmitter audio processing (within the DSP) at theinput of the preemphasis. It is fed in at a level below thelimiting threshold of the audio processing and factory calibratedfor a modulation index of 2.FREQUENCY DEVIATION CONTROL: The transmitter peak deviation iscontrolled digitally by a factory set deviation multiplierconstant which is stored in EEPROM (U4). D2 on the VCO PCB isswitched "on" during receive mode to switch VCO ranges and toinsure that no modulation is applied to the synthesizer duringreception.5.3 RECEIVER CIRCUITS:GENERAL: Refer to RF Mainboard Schematic Diagrams, Sheets 1 and2. The receiver is a double-conversion superheterodyne with atotal of 10 poles of receiver IF filtering.RECEIVER RF FRONT END: RF from the antenna passes through ahighpass filter to the low-noise RF preamplifier Q1. After passingthough U5, the signal passes through the three stage, top coupledbandpass filter consisting of L1, L2, L3 and their associatedcapacitors. The 50 ohm output of the bandpass filter is appliedto double balanced passive diode mixer, U3. The mixer is providedwith +7 dBm LO high-side injection from the VCO buffer through a 3dB resistive pad consisting of R11 and R12. The desired mixeroutput is the 21.4 MHz first intermediate frequency (IF).5-2
21.4 MHZ IF AMPLIFIERS: Q2, the first IF amplifier circuit usesa low noise JFET in the common gate configuration. This circuitprovides a wideband termination for the mixer, U3. L5,C12 andC9match the four pole 21.4 MHz filter comprised of FL2 and FL1 tothe output impedance of Q2. The input impedance of Q3, togetherwith L8, C15 and R7 match FL1's output impedance. The second IFamplifier 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 typeand is part of the multipurpose FM receiver chip, U1. Mixing thefirst IF of 21.4 MHz with the second conversion oscillatorresults in a second IF frequency of 455 KHz. This signal isfiltered by asix-pole ceramic filter FL3, and then passed on to the limiter-amplifier in U1. The second local oscillator frequency is thesame 21.850 MHz temperature stabilized crystal oscillator as themaster reference.QUADRATURE DETECTOR: The output of the limiter-amplifier of U1 isinternally fed to the quadrature detector whose phase shiftcircuit is provided by quadrature coil L6. The raw basebanddetected audio emerges from U1 on pin 9 (approximately 0.7 voltspeak-to-peak for a 1 KHz tone, 3 KHz deviation) and is fed to theCODEC (U6) to be digitized.DIGITAL DEEMPHASIS/VOLUME CONTROL CIRCUIT: The raw audio from U1pin 9 is fed to U6 the 16 bit CODEC and is digitally sampled at42.676 KHz. The digitized audio is then passed to the U5 the DSPwhere it split into two signals by a 3 KHz lowpass and a 3 KHzhighpass filter. The highpass filtered portion is fed to thesquelch process described below. The lowpass filtered portion ismultiplied by the digital volume setting value, then the digitalsquelch gate and output to the the CODEC, U6. U6 outputs thereceive audio on the line output left pin. It is then fedthrough R26, R52 and C68 which comprise the deemphasis network. Itis then passed through C2 to U11, the audio output amplifier.DIGITAL SQUELCH PROCESSING: As described above, the digitizedreceiver audio is filtered by a 3 KHz high pass filter and fed to the digital squelch process. It is similar to a traditionalnoise activated squelch. The DSP calculates the magnitude ofaudio energy above and below 3 KHz and uses this in conjunctionwith the squelch threshold setting to intelligently decide whetherto 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 RFamplifiers plus a hybrid RF power amplifier module which containstwo more gain stages. Overall gain is typically 40 or more dB.5-3
PRE-DRIVERS: The approximately +10 dBm signal from thesynthesizer is first amplified by Q9. The output of Q9 isnarrowband matched to the low impedance input of Q10 by L6 andC11. The output of Q10 (up to 0.6 watts) is matched into thenominal 50 ohm input impedance of U8. DC power for Q9 iscontrolled by DC switch Q1A.FINAL AMPLIFIERS: U8 is a hybrid amplifier containing two gainstages providing approximately 20 dB overall gain (25 watt mode)and 25 watts or 1 watt output as required. DC power for the finalstage is obtained directly from the fused 13 volt power source.5.5 ANTENNA INTERFACE CIRCUITS:TRANSMIT/RECEIVE SWITCHING: Antenna changeover between transmitand receive is accomplished by PIN switches D33 and D35. In thetransmit mode current from 13VTX passed through L7 and L1 to turnon D33 which passes transmitter RF. The DC current then passesthrough L8, D35 and finally to ground through R3, R122, R123 andR124. C6, L8 and C123 form a 1/4 wave matching section. When D35turns on it presents a short to ground through C120 and C121 forRF. This is reflected as an open circuit at the other end of L8. This isolates the receiver input from the transmitter RF. The DCvoltage on the cathode end of D35 is also coupled to the source ofthe receiver RF amplifier through L9 which biases it off providing further receiver isolation.TRANSMIT/RECEIVE FILTERING: A 7-section low-pass filter providesexcellent VHF and UHF harmonic rejection for transmitter harmonicsand receiver images. 5.6 AUTOMATIC RF POWER CONTROL (APC) AND TX LOGIC:In transmit mode a digital negative feedback control systemcontinuously monitors and , if necessary, corrects the outputpower level at the antenna terminals. C119 samples the RF voltageat the RF power amplifier output terminal. Diode D34 converts theRF signal to a DC level proportional to the output power level andthe DC signal is fed to A/D converter U15. The digitized signalis then applied to the DSC chip and subjected to a power controlroutine which, through D/A converter U17, drives DC amplifier (Q5and Q13) to provide the correct DC supply voltage to Q9 and thefirst stage of U16. This is turn creates the proper RF drive tothe 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 APCsystem will closely maintain the 1 W or 25 W output level (asselected) over a wide range of power supply voltage and ambienttemperatures. The final RF power amplifier stage cannot producemore than about 30 watts even in the unlikely event that theautomatic power control system should fail.5-4
5.7 TX LOGIC DETECTOR: The DC level from rectifier D34 which isused by the APC circuit above is also used by the DSP to determinewhen a power level of at least 1/2 watt is present. If it is, theDSP then turns on the TX annunciator on the front panel liquidcrystal display.5.8 POWER and AUDIO CIRCUITS:All receiver volume, squelch, beep and muting processes are donewithin the DSP U5. The processed audio is output through the CODECU6 to U11 where it is amplified up to 4 watts maximum power.Power for most of the internal circuitry is derived from the 13volt switched (13VSW) rail. This is derived directly from thefused and filtered input voltage from the main power source. The13VTX 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, the3.3 volt regulator operates from 5 volt rail. U7, the 1.8 voltregulator, operates in turn from the 3.3 volt rail. U14, theaudio power amplifier also operates from the +13VSW rail.Both the Receiver and the VCO modules operate from the 13VSW railand 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 TexasInstruments TMS320C5402U1. This chip in conjunction with U3, the FlashROM, U4 the EEPROM, and U6 the audio codec perform all of thesystem microcontroller as well as the digital signal processingfunctions. U3 contains the system firmware which is loaded intothe internal RAM of U5 at powerup. As a microcontroller U5controls all keypad, display memory storage, power management andother system functions. U5, in conjunction with U6, the audioCODEC also performs all digital signal processing functionsincluding receiver audio processing, filtering, volume control,beep generation, squelch detection and gating. All transmitteraudio processing and DSC modem functions are also provided by theDSP. An NMEA0183 input port is optically coupled to the DSPthrough U8. The DSP clock is the 21.850 MHz crystal controlled byXtal1, the frequency synthesizer reference. All baud rates andtiming functions are derived from this oscillator. Non-volatilememory functions (Scan lists, special channel programs, etc.) areprovided by U4, a 2K EEPROM. No memory backup batteries arerequired.RESET AND WATCHDOG PROTECTION CIRCUIT: U13 monitors the 3.3 Voltsupply to the DSP. At power on and at any time that the 3.3 voltsupply drops below 3.0 volts, U13 resets the DSP and keeps it5-5
reset for 200 milliseconds after the voltage returns to normal. Even momentary brownout conditions will reset the DSP. U13 alsocontains a watchdog circuit. Pin 4 of U13 the watchdog input mustbe strobed by the processor at least once per second or the DSPwill be reset for 200 milliseconds. This protects the radio in theunlikely 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 keykeypad. This keypad is of the conductive rubber type and isbacklighted with internal LEDs. Both the keyswitch stators andbacklighting components are part of the main PC board. Theindividual keys protrude through holes in the front panel bezel. Backlighting LEDs are configured in four series strings and lightlevel is controlled by the DSP through pin 2 of U17 the octal DAC. The DAC output is buffered and amplified by Q7 and Q8. Sixteenintensity levels are provided.5.11 DISPLAY/DISPLAY LIGHTING:DISPLAY: The front panel display is a LED backlighted LCD graphicmodule. Various display configurations are provided which permitthe operator to monitor all the various radiotelephone parameterssuch as channel number, power level, memory mode, etc. Thedisplay is controlled by the system DSP through U14, the LCDcontroller.5-6
6. MAINTENANCENOTE:In order to avoid making unnecessary adjustments it is bestto first assess the basic transceiver performance using the stepsoutlined in Section 6.3 below.6.1 GENERALBASIC DISASSEMBLY:NOTE: No disassembly of the unit is generally required forcalibration of the unit.1. Prepare a clean surface in the work area. Static-freeprecautions are recommended. Place radiotelephone on worksurface and remove the eight #4 self tapping screws whichfixes the front panel bezel in place. The front panel bezelmay now be removed, providing access to the interior of theradiotelephone.CHASSIS DISASSEMBLY:The Main PCB is not field removable from the chassis casting. Contact the factory for return authorization if the main PCB isdamaged.6.2 RECOMMENDED TEST EQUIPMENT:1. 13.6 volt, regulated DC power supply with ammeter, rated forminimum 6 amps continuous duty. (For 24 voltradiotelephones, substitute a 24 volt regulated DC powersupply with ammeter, rated for minimum 4 amps continuousduty.)2. 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.3. Volt-ohmmeter plus RF probe. eg: Fluke 75 plus Fluke 85RF probe.4. VHF frequency counter, accurate to 10 Hz resolution.5. Calibrated frequency deviation meter.6. Sinewave audio signal generator.7. Calibrated RF signal generator with FM capability, 50 ohmoutput impedance and minimum 40 watt reverse powerprotection.8. Audio distortion (SINAD) and audio voltmeter.9. Four ohm, four watt resistive load.10. Spectrum analyzer, 1 to 1000 MHz, 1 KHz resolution.11. Oscilloscope. (50 MHz bandwidth required for receiver first IF alignment.)12. 50 ohm, 20 or 30 dB RF power attenuator.13. VHF marine FM monitor receiver.6-1
6.3 BASIC PERFORMANCE TESTS:GENERAL:NOTE: No disassembly is required to perform basic performancetests. The orange audio output wire and the yellow internalspeaker wire must be connected together if internal speakeroperation is desired.1. DISPLAY/KEYPAD AND MAIN MEMORY CHECK: When the main power isturned on, the display will cycle through a self-checksequence. Following this self-check cycle, the front panelwill revert to the normal RADIO front panel indication.2. NON-VOLATILE MEMORY FUNCTION CHECK: Change the prioritychannel to a new channel number. eg: Select USA or INTchannel list, then push: 1. 3. ENT, FUNC,and 9 for morethan one second. Unpress 9 and wait one more second. Cycleradio power OFF then ON. Push 16 twice and verify that thenewly chosen priority channel number (13 in our example) isdisplayed. Reset the priority channel to the desired channelnumber (USA Channel 16 is recommended).BASIC TRANSMITTER TESTS:Set up the equipment as shown in Figure 6.1, "Transmitter TestSetup".1. TRANSMITTER FREQUENCY AND POWER CHECK: Key the transmitteron channel 16 (156.800 MHz). The frequency should readwithin + 780 Hz of the assigned frequency at roomtemperature. The wattmeter should read 25 + 2 watts in the25 watt mode and 0.7 to 1.0 watt in the 1 watt mode. Repeatthis test on channels 01 (156.050 MHz) and 88 (157.425 MHz). During transmission the TX annunciator should be ON wheneither the 1 watt or 25 watt mode is selected. The DCcurrent should not exceed 6amperes in the 25 watt mode (13.6 volt operation), or2.5 amperes in the 25 watt mode (24 volt operation).2. TRANSMITTER PEAK FREQUENCY DEVIATION CHECK: Key themicrophone on the desired channel and speak in to themicrophone in a normal speaking voice. Verify that the peakdeviation averages more than 4 KHz but does not exceed 5 KHz. Listen for "clean" sounding audio on a good monitorreceiver.3. TRANSMITTER AUTO POWER REDUCTION AND OVERRIDE CHECK: Set theradiotelephone to channel 13 USA. Verify that the 1 watt(1W) annunciator is ON and that the transmitter power is 1watt unless manual override is used (Holding down any keywhile transmitting). Repeat on channel 67 USA.6-2
BASIC RECEIVER TESTS:Set up the equipment as shown in Figure 6.2, "Receiver TestSetup".1. RECEIVER SENSITIVITY AND AUDIO POWER CHECK: Select the USAchannel list. Set both the receiver and signal generatorfrequency to channel 16 (156.800 MHz). Set the squelchthreshold open. Apply 1000 Hz sinusoidal, 3 KHz peakdeviation modulation to the signal generator. Start with thesignal generator set to approximately 1 millivolt (-47 dBm)amplitude.Set the volume to maximum. The audio voltmeter should readabout 4 volts RMS. Reduce volume to approximately 50% audiopower (2.8 volts RMS on the audio voltmeter).Reduce signal generator RF amplitude until 12 dB SINAD isobtained. This should occur at approximately 0.3 microvolts(-117 dBm) or less. Repeat check on channel 01A (156.050MHz) and weather channel 1 (162.550 MHz).2. SQUELCH SENSITIVITY CHECK: Turn off signal generator RFoutput. Increase the squelch threshold until the squelchjust closes. Start with the signal generator RF amplitude atminimum setting and increase slowly until the squelch justopens. The signal generator amplitude should not exceed 0.2microvolts (-121 dBm).3. MODULATION ACCEPTANCE CHECK: This test checks for properalignment of the receiver. Set the signal generator andreceiver to channel 16 (156.800 MHz). Set the signalgenerator modulation to 1 KHz sinusoidal, 3 KHz peakdeviation. Set the signal generator amplitude toobtain 12 dB SINAD. Increase the signal generatoramplitude 6 dB (double the output voltage) and thenincrease the peak deviation until the SINAD ratio dropsback to 12 dB SINAD. The final deviation should be 7KHz or greater.6.4 TRANSMITTER ALIGNMENT (TUNE UP PROCEDURE):GENERAL: Avoid making unnecessary adjustments. Some or all ofthe following procedures should be performed only afteridentifying specific problems during the Basic Performance Tests,Section 6.3 above.Transmitter calibration should be performed by qualified servicetechnicians using the proper test equipment and is only accessiblewith specific factory authorization. To obtain authorization,contact the factory with the serial number of the unit for anauthorization code.6-3
Enter the service menu by pressing FUNC-MODE and entering theservice menu activation code. The various adjustments areselectable by rotating the the front panel control and pressingmode when the desired adjustment is displayed. The service menuallows adjustment of deviation, clock frequency, 1W power level,25W power level. DSC transmitted high tone, low tone and dottingpattern are also available for testing purposes. During all of theservice 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 (unlockedcondition) all display annunciators will flash repeatedly, thecomputerized operating system will fail to respond andradiotelephone transmit function will be inhibited.1. Ensure that a 50 ohm, 25 watt power load or power attenuatoris connected to the antenna terminals. Ensure that the DCpower source is supplying 13.6 + 0.5 volts to the radio powerlead (Red lead positive, Black lead negative) under 25 watttransmit conditions. DO NOT EXCEED 16 VOLTS UNDER ANYCONDITION. If the transmitter is operated at 25 watts outputfor long periods, carefully monitor the temperature of thechassis for evidence of excessive heating.2. TRANSMITTER FREQUENCY: Place the radio on any desiredchannel. Enter the setup mode and select the “CLKTUN” mode. Push microphone push-to-talk button (PTT) to key transmitteron any desired channel. Rotate the front panel control untilthe transmitter is within 100 Hz of the assigned frequency. The display will show an adjustment of 0-200 and willtypically be approximately 100. Press “MODE” to store thesetting. All other transmitter and receiver channelfrequencies 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 25watt output level. Enter the setup mode and select the “25WADJ” mode. (NOTE: Avoid prolonged transmitter testing onthe emergency channel (16)). Key the transmitter and adjustthe front panel rotary control for exactly 25 watts output.Press “MODE” to store the value. Use a 25 watt wattmeterelement for maximum accuracy. Select “1W ADJ” in the setupmenu and temporarily adjust the front panel rotary controlfor minimum output power. The TX annunciator on the frontpanel display should extinguish, even though the transmitteris keyed. Change wattmeter element to a 1 watt unit formaximum accuracy and adjust for 0.95 watts. Press “MODE” tostore the setting. Change wattmeter element back to 25watts. Check channels 01 and 99 for 25 + 2 watts in the 25watt mode and 0.7 to 1 watt in the 1 watt mode. The TXannunciator should now come on in either the 1 watt or 25watt modes when transmitting.6-4
5. TRANSMITTER PEAK FREQUENCY DEVIATION:NOTE: The DSP transmit audio processing adjusts the audiogain to a wide range of audio input levels. The deviationadjustment sets the transmitter deviation level and is not amicrophone gain adjustment. Once properly factory set itshould not require readjustment for the life of the unit.Connect an audio sinewave generator to the microphoneterminals. If the audio generator amplitude cannot beattenuated below 5 millivolts at the microphone terminals,insert a 10 Kohm or greater resistor between the audio sourceand the external microphone terminal. Set the audiogenerator to 1 KHz. Enter the setup mode and select thedeviation adjustment as described above. Key the transmitterand watch the deviation meter while varying the audiogenerator for maximum deviation. Once the maximum is found,adjust the deviation adjust the front panel control for 4.8KHz peak deviation. The LCD display will show a deviationsetting between 0 and 200 and should typically be about 100.Press the mode key to store the deviation setting. Theresulting audio level at the external microphone terminalsshould be approximately 40 millivolts peak-to-peak or 14 mvRMS. Now set the generator to 2500 Hz and verify that thedeviation does not exceed 5 KHz peak under any amplitudecondition up to at least 400 millivots RMS at the microphoneterminals. Remove the series dropping resistor from theaudio generator path if necessary to achieve this audio drivelevel.Disconnect the audio generator. Key the transmitter andspeak loudly into the microphone to verify that the frequencydeviation does not exceed 5 KHz. Now speak at normal volumeinto the microphone and verify that the deviation averages 4KHz or more. NOTE: The particular damping characteristicsof the deviation meter must be taken into account since mostdeviation meters will overshoot on voice peaks. Listen for"clean" audio on a good monitor receiver.6. SPECTRAL PURITY: Connect a 1000 MHz spectrum analyzerthrough the power attenuator and verify that harmonics orspurious signals do not exceed -60 db with respect to 25watts (-16 dbm) during both modulated and unmodulatedconditions. Change to 1 watt output power mode and verifythat harmonics or spurs do not exceed -46 dbm with respect to1 watt (-16dbm) during both modulated and unmodulatedconditions. CAUTION! Spectrum analyzer overload will lead toerroneous results, especially at the transmitter harmonicfrequencies. To avoid overload, 60 or 70 minimum attenuationis usually required between the transmitter output terminalsand the first mixer of the spectrum analyzer, regardless ofthe center frequency and span being viewed.6-5
6.5 RECEIVER ALIGNMENT:GENERAL: The receiver is factory aligned and has no fieldserviceable adjustments. If specific receiver performanceproblems are identified, contact the factory for returnauthorization.6-6

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