Hammarlund_SP-600-JX-17_serv_user_1967.pdf

DESCRiPTIO. AND SP-600-JX17 COMMUNICATIONS RECEIVER FOR SINGLEANDDIVERSITY RECEPTION , . . :.TECHNICAL - - - I: l -OPERATING IINFirst MixerV5;FirstHeterodyneOscillator V4; four stagesofIFamplification, V7, V9,VIOandVll; Detector, AVC Rectifier V14; NoiseLimiterV15; BeatFrequencyOscillator V13;IFoutputandAF amplifier, V16AandV16B;OutputPowerStage V17,andthePowerSupplySystemwhich includes BPowerRectifier V19, CBiasRectifier C20andVol- tageRegulatorV18. Inthecircuitsfor double conversion,usedfor signalfrequenciesabove7.4 megacyclestheSecond MixerV6andSecondHeterodyneOscillator V8 are substitutedforthegatetubeV7. A preciserotaryturretisusedtochangebands. ItassociatestheRFtuner,sub-assembliesofthe antennacoupling,thetwo-stageRFamplifier,and thefirstheterodyneoscillator ofthebandselected withthecircuitryintheRFstripcommontoeach band.Inthisway, eachRFtunersub-assemblyis positioneddirectlyadjacenttoitsrespectivetube andgangsection ofmaintuningcapacitorCIA-CIH. INPUTCOUPLING-Theantennainputcoupling providesanoptimummatchfor a 95-ohm coaxial cable line connectedtoantennainputconnectorJ1. Onbands,1,2,3,and4,theantennaRFtransformer issecondary-tunedbydualsectionCIA-CIBofthe maintuningcapacitor;onbands5and6,bysection CIAonly. A capacitor,suchasC3 forband1,isused sothattheantennacircuittrackingmatchesthatof theRFamplifier. RFAMPLIFIER-TheVIandV2stagesofthe RFamplifier are identical,VIissecondary-tuned bydualsectionCIC-CIDwhile V2issecondary- tunedbydualsectionCIE-CIFofthemaintun- ingcapacitor. Complexed coupling isusedinRF stagestomaintainamoreconstantlevel ofsignal gainoverthefrequency levels ofeachband.High imagerejectionratiosare achievedthroughtheuse ofthreeHighQtunedRFcircuitsandbydouble con- versiononthethreehigherfrequencybands.The highgaindevelopedbytwoRFstagesassuresmax- imumsensitivityathighsignal-to-noiseratios. FIRSTHETERODYNEOSCILLATOR(variable V4)-FirstHeterodyneOscillatorV4functions asaColpittsoscillator forthethreehigherfrequency bandsandasatuned-gridoscillator forthethree lower frequencybands.DualsectionCIG-CIHof 2 themaintuningcapacitorprovides forthevariable tuningoftheoscillator.Forsingle conversion,the oscillator frequency is 455 Kchigherthanthesignal frequency, while for double conversiontheoscillator frequency is 3.955mehigherthanthetuned-in sig- nal. FIRSTHETERODYNEOSCILLATOR(Crystal Controlled V3) -Forservicesrequiringextremely stable, fixed-frequency operation, acristalcontrol- ledhighfrequency oscillator is provided.Instant change-overfromvariabletocrystalcontrolled os- cillatorwithachoiceofsixcrystalpositionsis effectedbyafrontpanelXTALScontrol. A second frontpanelcontrolmarkedDeltaFrequencyper- mitsa toleranceadjustmentofthecrystaloscillator frequencyoverthe+.005%(purchasedcrystaltol- erance) range. Fordouble conversion,theconversion oscilla- toroutputfrom V3 isaugmentedbyV4. Conversion oscillatoroutputfrom V3 is avail- ableatHFOoutputconnectorsocketJ8attherear ofthefrequencycontrolunitwhenthefrontpanel controlisinacrystalposition;butwhenthefront panelcontrolissettoitsEXTposition,theconver- sion oscillatorvoltageforthereceiveristhatwhich isexternallyconnectedtoJ8. INTERMEDIATEFREQUENCYAMPLIFIER-; Single conversionto455KC is employed forsignal frequencies below 7.4 me. There are fourstagesof IFamplificationincorporatingtheHammarlund- patentedfilter circuit.Sixpositionsof selectivity provide6dbbandwidthsof .2, .5, 1.3,3,8,and13 kc. Onthenarrowerbandwidthpositionsthecrystalfil- terisinoperation.Thecrystalphasingcontrolpro- videsextremeselectivityforthehighattenuationof closelyadjacentinterferingsignals. Double conver- sion isemployedforsignalfrequenciesabove7.4 mcs.Thesignalisheterodynedto3.955mebythe FirstMixerV5andHeterodyneOscillator V4,orV3 forhighimagerejection.The3.955mcssignalisthen heterodynedto455 KCbytheSecondMixerV6and the3.5meFixedCrystal-ControlledOscillatorV8 for selectivity.Fordoubleconversion,thetunedcir- cuitsandthe3.955meIFtransformerT2assureap- propriateinputtotheSecondMixerV6.IFtrans- formerTIintheplatecircuit of V5 isresonantto both455kcandto3.955 mcs.Forsingle conversion, the455kcsignalpathisto455kcIFgateV7; for double conversion,the3.955mesignalpathisto SecondMixerV6.Theprimefunctionof V7isto renderthesignalpaththroughitanopencircuitfor double conversionandavailabletothesignalfor single conversion. The3.5mecrystal-controlledheterodyneout- putfromV8isavailableatIFOconnectorsocketJ6 attherearskirtofthereceiver,whenthefrontpanel IFOswitchissettoitsINTposition;butwhenthe IFOswitchissettoitsEXTposition,the3.5mc conversion oscillator forthereceiver isthatex- ternallyconnectedtoJ8since V8 is now inopera- tive. DETECTORANDAVC -TheVI4tubeisusedas ahighlevelDetectorandAVC rectifier.TheAVC circuit isprovidedwithseparatetimeconstantsfor CWandMCWoperation. AVCandDiodeoutput terminalsprovidefor connectionsindiversityap- plications.TheAVCbiasdeveloped is appliedtoVI, V2, V6, V7,andV9,butthebiastoVIandV2 is re- ducedthroughuseof avoltagedividernetwork(re- sistorsR48andR53). TheBFO-AVCswitchprovideschoiceastoa FASTorSLOWtimeconstant.Sincetheswitch functions alsoasaBFOswitch, two positions,BFO FASTandBFOSLOW,are provided. BEATFREQUENCYOSCILLATOR-Thebeat frequency oscillator employs ahighcapacityCol- pittscircuit whichprovideahighorderof frequency stabilityandminimizes oscillator harmonics.The BeatFrequencyOscillator V13, is coupledintothe detectorcircuitthroughBuffer Amplifier V12, which eliminates oscillator lock-in. Afrontpanel control variestheaudio-beatfrequency from zeroto+3kc. Thebeatfrequency oscillatoroutputfromVI3 is available alsoatBFOconnectorsocketJ7atthe rearapronofthereceiver whenthefrontpanelBFO switch issettoeitheritsFASTorSLOWINTBFO positions;butwhensettoeitherofitsFASTor SLOWEXTBFOpositions,thefunctioningbeatfre- quencyoscillator forthereceiver isthatwhich is ex- ternallyconnectedtoJ7,sincetheoutputfrom V13 issuppressed. FrontpanelswitchcontrolMOD-CWrenders V13operativeforCWoperation.Anexternalswitch controlconnectedtoterminalsBFofremoteconnec- torsocketAN3102A-14S-2S (J4)ontherearskirt mayalsobeusedtoperformthisfunction, sincethese terminalsareinparallelwiththecontactsofthecon- trolswitch. Alternatetotheuseofthebeatfrequency oscil- latortorenderakeyed-carrierCWsignalintelligible, a localtonegeneratormaybeexternallyconnected toterminalsAandB ofJ4toamplitudemoduh;tte theCWsignal.Theuseof a localtonegeneratorpro- duces asteadytoneevenwhenthereceivedcarrier frequency drifts.J4isfurnishedwithconnectorplug AN3108B-i4S-2Pandcable clamp AN3057-6. NOISELIMITER-Thenoiselimitercircuit V15 limitsthenoise interference fromignitionsystems orothersources ofpulse-typenoise. Aseparate limitercontrolswitchpermitsoptionaluseofthe limiteronanymodeofoperationwhenpulsetype interference ispresent. AUDIOFREQUENCYAMPLIFIER-Aresis- tance-coupledamplifiertriodeVI6Bamplifiesthe audio-frequencysignalfromthedetector. AUDIOOUTPUT-TheaudiooutputtoV17 is transformer-coupledthroughasplitbalancedwind- ingtodeliver 2.0wattsundistortedoutputtoa 600- ohmload.Thesplitbalancedwindingpermitsbal- ancingofthedirectkindintheoutputcircuit,as usedforteletypeorsimilar service. Aseparatesec- ondarywindingprovidesattenuatedaudiosignal outputforheadphoneoperation.Thiswindingwill deliveranoutputof 15milliwattsintoan8000-ohm resistiveloadwhenthe600-ohm powersecondaryis delivering 500milliwattstoa 600-ohmresistiveload. IFOUTPUT-Acathodefollower,VI6Aprovides a 70-ohmimpedancesource ofintermediatefre- quency(455kc)tosocketSO-239ontherearskirt ofthechassis.PlugPL-259,andangleplugadapter M-359usedwithcoaxial cableRG-ll/Uarenotsup- plied. POWERSUPPLY-Thepowersupplyisaninte- gralpartofthereceiver.ItincludestheB rectifier V19andC rectifier V20,togetherwiththeirrespec- tivelow-passfiltersandVoltageRegulatorV18.The powertransformerisprovidedwithscrewterminal primarytaps,covering a power line sourcerangeof 90to270 volts,50to60cycles.Thepowertrans- formerandfiltercomponentsareprotectedbyfuses intheprimaryandplatesupplycircuit. TUNINGMETER-Thetuningmeterisusedon AVCoperationtoindicatetheaccuracyoftuning andtherelativestrengthof received signals. Depres- sion oftheMeterSwitchconvertsthemetercircuit forindicationofoutputlevelindbfrom 6 milli-watts. RFGAINCONTROLANDPOWERSWITCH- TheRFgaincontrolisprovidedformanualcontrol ofsensitivitytopreventoverloadingonstrongsig- nalswhenoperatingwiththeAVC-MANUAL switchintheMANUALposition.Thiscontrol alsooperateswhentheswitchis intheAVC po- sition.ThePowerON-OFFswitchisoperated atthecounter-clockwiseextremityoftheRFgain control. SEND-RECEIVESWITCH-Thesend-receive switchdesensitizesthereceiverbutleavesthepower ontoprovideforinstantreceptionbetweentrans- missionperiods. RADIATION-Advanceddesignandshielding of thehighfrequency, second conversioncrystaland beatfrequency oscillatorshasreducedradiationto a negligiblepointsothatinterference ofthisnature, commoninmulti-receiverinstallations,isreduced toaminimum. 3 SECTIONIII INSTALLATION TUBESANDPACKING-Afterunpackingthe receiver seethatalltubesare firmlyintheirsockets andthatallpackingmaterialisremovedfromthe receiver. POWERSUPPLY-Makesurethattheprimary tapleadatthebottomofthepowertransformeris connectedtothetapwhichmostnearlyagreeswith the50to60 cycle power source voltage. Power con- nectorplugAN3108B-18-3Swithcableclamp AN3057-10withpower cordandplugarefurnished withthereceiver. ANTENNA-Theinputimpedanceattheantenna socket, SO-239,isdesignedtomatcha95-ohmcoax- ial cable line.TheplugconnectorPL-259,andangle plugadapterM-359,suppliedwiththereceiver,are forusewithRG-ll/Ucoaxial cable(notsupplied). SPEAKER-Thespeakershouldbeoftheper- manent-magnetdynamictypeandshouldinclude aspeakervoice coilto600-ohmline-matchingtrans- former for connectiontothe600-ohm audiooutput terminalsofthereceiver.Caution:Whenthe600- ohmoutputisnotusedconnecta 600-ohm,2-watt resistortotheseterminalstoavoidcomponentda- magefromhightransientpeakvoltages.Forappli- cationsrequiringtheinsertionofdirectcurrentcon- trolorindicatingvoltages,thejumperconnecting thetwobalancedsectionsofthe600-ohmoutputmay beremovedandtheinsertioncircuit,suchasa low re- sistancebalancingpotentiometer,connectedinits place. HEADPHONES-Eitherhighorlow impedance headphonesmaybeusedbyplugconnectiontothe phonejacklocatedatthelower leftsideofthefront panel.Thehighimpedancetypeis recommended. MOUNTING-Thereceiver isdesignedforrack mounting.Topandbottomcoverplates aresupplied formountinginastandard19-inch rack.Thepanel is10-1/2incheshigh.SeeSectionVII.Thereceiver shouldbeplacedinapositionwhichpermitsthefree access of air. CRYSTALSFORFREQUENCYCONTROL- CrystalsY1toY6 arenotsuppliedwiththere- ceiver,butwillbesuppliedonspecialorderforany signalfrequencywithintherangeof from 2to30 megacycles.Inordertoinsurecorrectcrystal-con- trolled frequencyoperation,crystalunitsmaybe ordered fromTHEHAMMARLUNDMFG.CO. Theordershouldspecifythesignalfrequency for whicheachunitistobeused. Seenoteatendoi page30. Toinstallcrystalsloosentheknurled thumbscrewontopoftheCrystalControlUnit T34andpushtotherear.Insertthecrystalsin 4 thesockets.Bringtheretainerspringassembly forward sothatthespringspressontopofthe crystalholders,andtightenthethumbscrew.Mark thesignalfrequency for which eachcrystalwas selected in megacyclesontheplasticchartpro- videdforthispurposealongsidethecrystalswitch S2. Pencilorinkmaybeusedandcanbeerasedif itisdesiredtochangethesefiguresatanytime. Thenumeralsonthechartshouldbeusedsothat theyagreewiththenumeralsonthecrystalsocket positions, which are alsoindicatedbythecrystal selector switch. RELAYCONNECTIONS-Ifexternalrelay ope- rationforthesend-receive function is desired, con- nectionmaybemadebysoldering atwinconduc- torcabletotheterminalsoftheSend-Receiveswitch S9.InthiscaseS9isleftintheSendorOpen position. AVCANDDIODEOUTPUT-Indiversityap- plications,thediversityfeature isaccentuatedby interconnectingtheAVC(-)busbetweenreceivers, andutilizing acommonground(G) connection. This AVC connection ismadewhentheIForAFoutput ofthesystemisusedtoprovide fortheintelligence duetoaCW,MCW,orfrequency-shiftsignal;but for voicesignalsonlytheaudiooutputfrom one re- ceiver is used.Thisis donebyremovingtheDIODE OUTPUTjumperoneach receiverapartfrom one; andconnectingthenegative(-)terminalofeachto thatoftheone whoseterminalsremainjumpered. IFOUTPUT-TheIFoutputsocketSO-239atthe rearskirtprovidesthesignalat455kc fordiversity receivingsystemuse. ConnectorplugPL-259and angleplugadapterM-359 (supplied)shouldbeused withRG-ll/Ucoaxial cable(notsupplied).Theout- putprovidedtoa 70-ohmresistiveloadisapproxi- mately200 millivolts fornormalsensitivity(2 micro- voltsinputsignal). MASTERSLAVECONNECTIONS-Indiversity applicationsthemonitoringrequirementsimposed ontheoperatoraresevere,butmaybekeptata min- imumbyuseofcommonconversionandbeat-fre- quencyoscillators.Thentheoperatorneedconcern himselfmostlywiththesignallevelineachchannel andthesignaltuningofthereceivers. Toprovidefor V-3 crystal-controlledfirstheter- dyne,and/orV-83.5 me. crystal-controlled hetero- dyne,and/orV-13 beat-frequency oscillatoroutput, respectively, fromthemastertotheslave receiver, theHFO,IFO,andBFOsocketsSO-239,atthe rearskirt,eachfurnishedwithplugPL-259,and angleplugadapterM-359 forIFOandBFOonly, areinterconnected.ThecoaxialcableRG-l1/U suitedfor use isnotsupplied. Withtheredfrontpanel controlsineach in- stanceonone receiversettoaredpanelmarking, thatreceiver becomestheslave receiver, whereinits V3HFO),V13 (BFO)anditsV8(IFO)are rendered inoperative. REMOTECONNECTOR-TheREMOTEconnec- torJ4is furnishedwithconnectorplugAN3108- 14S-2Pandcable clamp AN3057-6. UseterminalsA andB of J4 for connecting a localexternaltone sourcetomodulatea CWsignalanduseterminals CandD of J4toperformthefunction oftheCW- MODswitchbyanothersystempanel switch, if de- sired. 521 19166 94 133 12 1.SENDRECswitch 2.IFOEXTINTswitch 3.HFOVAREXT XTALSI2 3 4 5 6 switch 4.BFO-AVCEXTBFO SLOWFASTINTBFO SLOWFASTswitch 5.PHONESjack 6.BANDCHANGEcontrol 7.MEGACYCLESwindow 8.Maintundingdial 9.Vernier Dial . 10.TUNINGcontrol 11.TUNINGLOCK 12.Plasticchart 13.HFO6.FREQcontrol 14.rtFGAINcontrol 15. AVCMANswitch 16.METERRFAFswitch 17.MODCWswitch 18.BEATOSC control 19.SELECTIVITYswitch 20.XTALPHASINGcontrol 21.LIMITEROFFswitch 22.AUDIOGAINcontrol Figure1.Radio Receiver,FrontPanelView 5 SECTIONIV OPERATION GENERAL-Beforeattemptingoperation ofthe SP-600-JX17 receiver,theoperatorshould thorough- ly familiarize himselfwiththefunctionsanduses of thevarious controls.Whenreferringtothecontrols inthisdescription,thewordsincapitallettersre- presentthepartofthenameadjacenttothecontrol onthefrontpanelorontherearskirtofthechassis. Forexample, when referringtotheSELECTIVITY control,theword,SELECTIVITYincapitals indi- catesthelegendappearingadjacenttothecontrol. Referencetophotographs,Figs. 1and6,issuggested while readingthisdescription.Frontpanel controls anddials are showninFig. 1andrear controlsand terminals are showninFig.6. SELECTIVITYCONTROL -TheSELECTIVITY control is a 6-position switch which selectsthree crystalsandthreenon-crystaldegr