DIYFM发射机200mW.docx

DIYFM发射机200mW.docx

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DIYFM发射机200mW

DIY-FM发射机200mW

 TX200HighQuality200mWFMTransmitter -usesregularNPNtransistors（withoptionalPLLmodule）

  PartsList:

R1-47K

R2-22K

R3-39K

R4-100

R5-27K

C1,C2,C4,C5,C9-1n

C3-4.7uF

C6-15pF

C7-6.8pF

C8-75pF

C10-100nF 

C11-2pF 

C12-10pF 

C13-100uF

Q1,Q2-BF199

L1-3.5turns/5mmdia.variablecoil（65nH-80nH）.

L2-Ferritebead1turnoruse1uHinductor.

  TechnicalSpecifications:

SupplyVoltage:

9V

PowerConsumption:

35mA

RFPower:

200mW

AboutTX200-200mWFMTransmitter 

HereisthelatestandgreatlyimprovedTX200VFO/VCOFMtransmitter.ThemostversatiletransmittertodatethatcanbeturnedintohighfidelitystereoPLLbased200mWFMtransmitter.Itisaperfectcircuitfortransmittingyourmusicaroundthehouseandyard.TX200usesonlytwocoils;oneintheoscillatorandtheotheroneinthe200mWVHFamplifiersoitshouldbefairlyeasyforanyonetobuild.Italsoincludesbuilt-inpre-emphasisandC5forenhancedsoundquality.WhileassemblingthetransmittercaremustbetakentomakesurethatC1isdirectlyconnectedtoL1andC9toL2.ThesecapseliminatethedistortionsformtheDCsupplyandimprovethesoundqualitygreatly.9VvoltagesupplyisalsoveryimportantbecauseitprovidestheexactamountofcurrenttoQ1toproduceloudandclearsoundquality.Ihopethatyou'llhaveasmuchfunasIhadwhilebuildingthistransmitter.Enjoy!

;）

PowerMeter

TX200comeswithbuilt-inLEDbasedpowermeter.Thisisaveryhelpfultoolthatwilltellyouifyourtransmitter'soscillatorisworkingproperly.IfRFsignalistransmittedtheLEDwillilluminate.Besidesthat,itwillalsogiveyouaquickvisualwaytocheckhowmuchpowerisbeingtransmitted.IhighlyrecommendthatyouhavethetransmitterandpowermeteronthesamePCB.Ifyouliketoexperimentalot,youwillappreciatethisinexpensivebutexternallyhelpfuladdition

HowtousePLLtodigitallytunethefrequencyoftheTX200transmitter?

IfyouwanttousePhaseLockedLoop（PLL）todigitallytunethefrequencyofTX200thenyouwillneedtomakesmallchangestothetransmitter'soscillator.Theoretically,changeoriginalvariablefrequencyoscillator（VFO）tovoltagecontrolledoscillator（VCO）.PLLusesvoltagetochangethecapacitanceofthevaricapdiodes/frequencyoftheoscillatorsotwoBB105varicapdiodesorany15-30pFvaricapswillbeperfectforthis. 

Youvarythecapacitanceofthevaricapdiode（s）byapplyingvoltagesupplybetween1-8V.Ifyouapply1Vthecapacitancewillbearound34pF,andifyouapply8-30Vthecapacitancewillbe12pF（minimum）.Now,youmaywonderwhydoweneedtostartfrom1V?

Thereasonisthatifyouapplyvoltagesbelow1Vthecapacitancemaygoashighas200pFandwesimplycan'tusethat.100Kresistorwillbeusedtolowerthecurrentofthevoltage,becausevaricapsrequireonly0.2mAofcurrenttooperate!

WiththisknowledgewereplaceC6-15pFcapacitorwithtwovaricapsandoneresistor.Thatmuchisenoughtobeabletouse1-8Vvoltagetochangetheoscillator'sfrequency.Thesecondchangethatwewillneedtomakeistouse2pFcapacitorandconnectittotheQ2transistor'scollector.PLLwillusethistosamplethefrequencyandcompareitwithdigitallyselectedfrequency.PLLwillthencomparethosefrequenciesandiftheyarenotthesamePLLwithvarythevoltagethatisappliedtothevaricaps,untilthosetwofrequenciesarethesame.

BeforeyouevenconnectPLLcircuittotheTX200transmitteryouwillneedtotestiftheoscillatorisworkingproperly.WecantunethroughentireFMband（88-108MHz）byapplyingthevoltagetothevaricaps.Todoso,connect"PLL-VoltageControl"PINtothe10Kpotentiometerasshownbelow.Withthissetupyouwillbeabletousepotentiometertochangethefrequencyofthetransmitter.Ifyoucan'tgothroughtheentireFMbandorifyourfrequencyisoutcompletelythenyouwillneedtochangetheinductanceoftheL1coil.

PLLModule

TheschematicandinstructionsforbuildingthisPLLmodulecanbefoundat pira.cz.AfterbuildingitanddoingsometestingwithitIwasamazedbyhowwellthisPhaseLockedLoopcircuitperforms.It'sstable,compact,veryeasytobuildandconnectingittoTX200transmitterwasapieceofcake!

MakeTX200aStereoTransmitter!

YoucaneasilyturnTX200intoahighqualitystereotransmitterbyconnectingthisstereoencodermodulethatyoucaneither buildityourself or buyitasakit.StereoencoderkitincludesallthehardtofindcomponentssuchasNJM2035ICand38KHzcrystal.

TX200PrototypeImages

 BA1404HI-FIStereoFMTransmitter-SpecialEditionKit

Be"OnAir"withyourownradiostation!

BA1404HI-FIStereoFMTransmitter-SpecialEditionKitisanexcitingtransmitterthatwillbroadcasthighqualitystereosignalin88MHz-108MHzFMband.ItcanbeconnectedtoanytypeofstereoaudiosourcesuchasiPod,Computer,Laptop,CDPlayer,Walkman,Television,SatelliteReceiver,TapeDeckorotherstereosystemtotransmitstereosoundwithexcellentclaritythroughoutyourhome,office,yardorcampground.Add 500mWFM/VHFTransmitterAmplifier/Booster forevenlongerrange. 

SpecialEditionBA1404HI-FIStereoFMTransmitterKitincludespremiumcomponentswithaudiogradegoldcapacitors,1%MetalFilmResistorsandqualityPCBwithRedSolderMaskandPlated-ThroughHoles.ThekitisbasedonthepopularBA1404stereobroadcasterICwhichcontainsallthecomplexcircuitryforgeneratingthestereoFMsignal.38KHzcrystalprovidesarocksolidstabilityofsub-carrierforstereosignal. 

Specifications:

VoltageSupply:

1.5-3VDCInput（SingleorTwoAA/AAAbatteries） 

Frequency:

88MHz-108MHz 

AudioInput:

Stereo 

PCBDimensions:

49mmx32mm（WxH） 

KitComponents 

  1xBA1404StereoFMTransmitterIC 

  1xPCBwithRedSolderMaskandPlated-ThroughHoles 

  1x38KHzCrystalOscillator 

  1x3.5TVariablePrecisionRFCoil 

  1x10uHInductor 

  4x10uF/50VGoldAudioCapacitors 

  4x1nFCeramicCapacitors 

  2x1nFMylarCapacitors 

  1x220pFCeramicCapacitor 

  5x10pFCeramicCapacitors 

  2x47K1%MetalFilmResistors 

  2x27K1%MetalFilmResistors 

  1x150K1%MetalFilmResistor 

  1x5.6K1%MetalFilmResistor 

  1x2701%MetalFilmResistor 

  1xInstructions