Browning-35-rec-sch 电路图 维修手册.pdf

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1、154 SHORTWAVECRAFTforJULY,1935 One of theimportantfeaturesof the Browning35 All-Wavereceiveris thatcontinuousband-spreadis availableon all bands. .FUNDAMENTALLY, the onlyreal excuse fora radioreceiverin kit form is thatit should provide a better set for less money where the builder is willingto do h

2、is own assemblingand wiring. The complete set market is sur- feitedwithcheapandmedium-priced sets builton a largeproductionbasis whichgive fairor indifferentresults. Such receiversare usually worth about what they cost and are cheaper to buy than to try to build.But in the more exclusive field of re

3、ally high-class radio receiversthe marketis far from being overcrowded.The few sets of this type which are availableare expensiveand beyond the reachof the averageradio fanspocketbook. It was to meet the requirementsof the radio experimenterwho wantsthe finest resultsand who is willing to do someof

4、theworkhimselftoobtain them economically thatthe Browning 35 was developed. Low Noise-LevelBoosts DX In designingthisreceiverwe have The. . BROWNINC 35- AII- WaveReceiver hadconstantlybeforeuscertainre- quirementswhich must be met:- In the first place it should be a really fine modern receiver,which

5、 meantan an.wavesuperheterodyneincorporat- ing a stage of efficient radio frequency amplificationon all bands. Secondly,it musthavea satisfac- tory quality-selectivitycompromise.It is a simple matterto designan ultra selectivereceiverwith poor reproduc- tioncharacteristics.Or, good repro- ductionis

6、no problemif broadtuning is allowed.Combiningthesetwo re- quirementsin the same set is a differ- ent .story and requiresthe utmost care in circuitdesign. Next this receiver must be capable of not only good long distancereception butof the veryfinest distancerecep- tionpossiblewithpresenttubesand sta

7、ndardequipment.We have persisted inthisrequirementfromthebegin- ning, as much of the pleasureand fas- cinationin an all-waveset lies in the satisfactoryreceptionof foreignsta- tions.To accomplish this result,(and By Clenn H. Browning The Browning 35 receiver was especially designed to be readily ass

8、embled by the averageshort-waveexperimenterandit provides band-spreadon all bands.The set covers the complete range from 13.2 to 555 meters. we feel that we can safelysay thatit has been accomplishedin the Brown- ing35)one requirementstandsout above all others,namely,a low noise- level! Adequatesens

9、itivityis of course necessarybut if carriedtoo far this is often more of a liability than an asset. What we are afteris good signal vol- ume with the least possible noise. Ingeneral,thesearethefeatures which distinguishthe reallyfine radio receiversfrom the mediocre ones. Our final requirement,which

10、 was the most difficult of all to meet, was thatthis receivershould be so designedthatit could be easily assembled by the aver- age radioexperimenter,withtheas- surancethatwhenthejob wascom- pletedit would retainall of these de- sirablecharacteristics. This last requirement,which we con- fessseemed

11、almostinsurmountableat first,was finallyaccomplishedby the use of a new piece of radio equipment -theTORE,SUPER-TuNER. (Continuedon page 174) . FIELDCOIL 1,800 OHMS -., - eF. (EACH) / 5,000 OHMS SW NOTES 1 .-TUNER.CONSISTS OF FOUR-SETS OF COILS L1,L2.L3,L4.LS,L6WITH TUNINGAND TRIER CONDENSERS AND CH

12、ANGE OYER. SWITCH !DR !DUll. BANDS(MOUNTEOWITHIN ONECAN) 2:-0IOIIITS WHERE COILSARESWITCHEO(DIA- GRAMSHOWSONLYONESETOFCOtLS) 3:-RESISTORSALL /4 WATT UNLESS OTHERWISESPECIFIEO Wiringdiagramfor the Browning35, showingthe simpleand straightforwardarrangementof thevariousstages,includingthe beatoscillat

13、or. RadioFans.CN 收音机爱 好者资料库 174SHORTW AVECRAFTforJULY,1935 600 Short-Wave 4.Stations arelistedinthismagazine! WEAREhappyto presentto thethousandsof shortwavefansthis new magazinewhich enthusiasticreadersof ShortWave Crafthave urged us to publish.Here is a book thatyou will feel proudto possess becau

14、se it reflects your patienceand perseverancein loggingdistantstations.It is a recordyou will be proudof in days to come.It is the finestand most completebook of its kindever published.Thereis nothinglike it on the marketnow, nor was thereever a book publishedlike it before. 4600 SHORTWAVESTATIONS It

15、containsthelargestlistingofshortwavestationsin theworld,a much largerlist in factthanthe list publishedin SHORT WAVE CRAFT, oranyothermagazine.Due to spacelimitations,no regular magazinecanpublishallthe worldstations.Thereareso many shortwave stations,which normallycannotbe includedin anymonthlymaga

16、zinelist,but frequentlyyouhearthesecalls andthenyouwishtoknow fromwheretheyoriginate.The OFFICIALSHORTWAVE LISTENERgives you this infor- mation,besides a lot of other in- formationwhich you mUOltha-e. NEW Short Wave Listener Outof Tunc . ASK YOUR NEWS DEALER FOR A COpy OF THIS NEW SHORT-WAVE MAGAZIN

17、E . 2SctileC81Y Well lllustrat4 . Contents01 theJldfllssue: TalkingAroundthe WorldBy ShortWaves Short- WavesStarsof StationPHI,Holland. Whereto Find the Short-WaveStationson YourTuningDiL How to Get MaximumResultsfrom Your SW Set by George- The LatestStylein DoubletAerials Why Is a Multi-TubeSet Sup

18、eriorto a 1 or 2 Tube Set? Short-WaveUFictionStory Photosof Short-WaveArtistsFromIndia,U.S.S.R.,and Other SilverCup TrophyContestfor the BestListeningPostPh. GrandListof ShortWaveStationsof theWorld-Withea.:.Lee Frequencies.IncludingPoliceand TelevisionStations StarShort-WaveStationList NewestIdeasi

19、n ShortWaveReceivers MusicalSignaturesand ForeignLanguageAlphabets-Ac.- IdentifyingStations TheListenerAsks-ShorbWaveQuestionBox Fromthis you will see thatth(magazinehas been dE a companionmagazineto SHORT WAVE CRAFT. If you arenow a readerof SHORTWAVE CRAFT you will not wish to be withoutTHE OFFICI

20、ALSH E7 LISTENERMAGAZINE.Thenew magazinewill he:;- mendouslyin yourshortwavereceptionatall tim give you priceless and invaluable information, such a,: _ _I . getanywhereelse.Nothinglikeit appearsin priD today.THEOFFICIALSHORTWAVE LISTENER in otherwords, is a necessity. P. S.-Ifyou cannotget the maga

21、zineat your neWSSc_-.- sell-out,send25c in cash,stampsor moneyorder.-.- send the magazineto you direct,prepaid. OFFICIAL SHORT WAVE LISTENER L-.G;.:- I 99 Hudson Street, New York, N.Y. Please mention SHORT WAVE CRAFI -.: The Browning 35-AII- Wave Receiver (.continuedfrom page 154) TheHeartof the35 T

22、histuneristheheartoft!le Browning35aroundwhichthesetis built.It containsin a single unitthe 3- gangvariabletuningcondenser,withits verniercontrol;twelvetuningcoils, three foreachof thefourseparatefrequency ranges,in separateshielded compartments; a trimmingcondenserfor each one of these twelve coils

23、, togetherwith the variableand fixed paddingandtrackingcondensers. The SUPERTUNERalso containsa silver- plated, multipleband, selector switch which passesthroughtheshieldedcompartments withacoil-switchingunitineachcom- partment.By means of the uniquewiring arrangementof thisswitchthecoilsnot in use

24、are isolated and short-circuited.The individualpartsof theunitarecarefully arrangedandspacedfromtheshielding wallsto keepinductivelossesandstray capacitiesat a minimum.Not only is the SUPER-TuNER completelyassembledand wired at the factory,but thecircuitsand trimmingcondensersarealsoalinedand preadj

25、usted;theR.F.detectorandoscil- :a.or circuits are all synchronizedand ready , operate.Thus the complicatedand crit- partof theelectricaland mechanical a;.asauetionis eliminatedand the remain- =:;6S:5embl andwiringworkonthe ,;scanbe doneby anyonefamiliar -.;.e use of solderingiron,pliers,and -.;- .;:

26、ri-er. rlliqaeConstructionPlans E-!ed ;heproblemof how the 20- =oIL _ .onstructsuch an advanced _.;-utilizingtheSUPER-TuNER, _-.- torn was thattheremaining .- .-_-.ringwork should be made _- _-.proof as possible.Accord- _ -2Ie drawingsare furnished inefirstshowsalarge -0M.f the circuit.Drawing _-;Q

27、assembletheparts. -wlall wiring on the -tJae filamentandpower nsitivityandvolume He.DiagramNo.4 . of every fixedresistor Diagram No.5 shows ,nnecteachfixedcon- -.;ng, except the sev- 1:. are made lastof all - _.ageof tuned R.F. ;jon,as it is some- usedaheadof the bandsreallyam- =-the circuitis not _

28、 :. will prove more - _set on the high thesensitivityin- Silver-platedwire IUency tuningcoils rcircuits,and - RadioFans.CN 收音机爱 好者资料库 SHORTWAVECRAFTforJULY,1935 everyprecautionistakentoeliminate resonantcircuitlosses ahead of the mixer tube.It is thispartof the circuitwhich mustbe dependedon to elim

29、inateimage and pseudoimagefrequencieswl1ich are so annoying,even in manyof the higher- pricedreceivers.Moreover,ifareason- ablyhighorderofamplificationcanbe obtainedin thispreamplifier,andthisis View of Tobe Tuner entirelypracticablewiththe help of a 58 supercontroltubeandlow-losscircuits, itpermits

30、theuseoflessintermediate frequencyamplificationwhichhelpstre- mendouslyinreducingthenoise-levelof the entirereceiver. TuningRangefrom13.2 to 555 Meters TheBrowning35coversthewhole shortandlongwavebroadcasttuning rangeupto555meters,ortheentire frequencyspectrumbetween22.6 and.54 megacycles.Itssensiti

31、vitythroughout thiswide rangeis betterthanone micro- voltwhichmeansthattheR.F.gainis greaterthancan be used except under the mostfavorableatmosphericconditionsin a veryquietreceivinglocation.It can be seen fromthe accompanyingsensitivity curvesthatthe responseon anyoneband is almostuniformwhiletheen

32、tirevari- ation over all four bands is unusuallysmall. The uniformityof these curvesis a direct indicationof the high efficiency of the all- wave tuningunitemployed. The receiveris absolutelysingle-control. The twelvetrimmingcondensersandfour trackingorpaddingcondensersinthe SUPER-TuNERunit make it

33、possible to main- tain accuratesynchronismbetween the pre- selector,detectorandoscillatorcircuits over theentirefrequencyrange. Band-SpreadOverEntireRange Tuningisdonewitha40 to1 ratio microvernierdial.Stationsarelogged by referenceto two pointers,one on the main shaftofthetuningcondenserandthe othe

34、ron theverniershaft.The vernier dial has a 21., diameterand covers 3600. Thuscontinuousband-spreadisaccomp- lished over theentiretuningrange.The advantageof suchtuningcontrolcanbe seenby consideringone individualband. Take,forinstance,thehighestfrequency bandwhichtunesfrom22.6 megacycles (13.2 meter

35、s)to 8.8 megacycles(34 me- ters).On thelargecalibrateddialthis band is 81., long.While the long point- er on the maindial is coveringthisdist- ancethevernierpointermakes20 com- plete revolutionson its 21., scale, covering actually15%.The 20-meteramateur phoneband,whichis only100 kilocycles wide, cov

36、ers 720 on the 2%vernierdial! OscillatorIsElectron-Coupled Thebeatfrequencyoscillatoris combined withthefirstdetectorandelectronically coupledtoitinthe2A 7 tube.Thispre- cludesanylocking-ineffectsbetweenthe antennaorR.F.stageandtheoscillator. Anotherfeatureof theoscillatorcircuitis theparallelvoltag

37、efeedtotheanode. Thiscanbeseenbyreferencetothe accompanyingschematiccircuitdiagram, wherethe20,OOO-ohm resistoris shownin serieswiththepowersupplyandin parallel withtheplateinductanceof theoscillator. Thiscircuitarrangementtendsto keepthe R.F.outputoftheoscillatoratacon- stantleveloveritstuningrange

38、andper- mitsmoreefficientoperationofthemixer. DoubleBand-PassFilter Only one stage of intermediatefrequency amplificationis used.This was done delib- eratelyin preferenceto using two or more stages,and not forthesakeof economy. The58 super controltube,whichis used here,hasan amplificationfactorof 12

39、80 and,whenusedwitheffectivehighim- pedancegridandplatecoupling,is cap- ableofdeliveringasmuchintermediate R.F.amplificationascanbe usedunder actualoperatingconditions. Itis commonpracticeto makeuseof twoor moreintermediatestagesof am- plificationoperatingat low efficiency, each slightlyoff resonanc

40、ewiththeother,in ordertoobtainaselectivityandampli- ficationcurvewhichisnottoosharply peaked.While thisis good theory,from a practicalstandpointtheresultsarenot alwayssatisfactory.Tube capacitiesvary, theircharacteristicschangeand tunedcir- cuitsshifttheirpeaks.An oscillator,to- getherwithan oscillo

41、graph,are necessary to properlyreadjustsuch an I.F. amplifier. TheBrowning35makesuseofa double band-passfilterto accomplishthis purpose.Six tunedcircuitsare employed in thisone I.F,stage,two of thesebeing linkcircuitswhichareconductivelycon- nected only to ground, and are consequently not affected b

42、y tube variations,etc.Three ofthesefiltercircuitsarecontainedin eachofthetwoI.F.transformers,the centerone ineachcase beingtheinde- pendentlink circuit.Itis a simplemat- tertoalignthesecircuitsatanytime by merelyadjustingthetwooutsidecir- cuitcondensersineachtransformerso thattheircircuitsarein reso

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