AN-ARC-5_T-23_test_unit_1965.pdf

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1、 A TestUnit ForThe BY BYRON E. FORTNER*.W9FYM F ORthe past several years.articles have been writtenabout the T-23/ARC-S v.h.I. trans- mitterand presentarticlesattest to the popularityofthis finetransmitteronthetwoand sixmeterbands. Atthepresent time. nothing has beensaidor nothingisknownofthe test u

2、nitthatwasorigi- nally designedtotuneup the T23/ARCj trans- miller.Theauthoris thefortunatepossessorof the testunitanditis thepurpose of this article todescribeitand showthatitcanbeduplicated very easily. The test unit is knownasthe U.S. Army Signal CorpsTest Unit 1-155-A and was buillbyWest- ern-El

3、ectric.Itconsists of an 0-1rna meter with a functionswitch and appropriate resistors to bringthemeterin theproperrangeforthe cir- cuitbeing tested. A tuning stick isincludedin a compartmentwith a slidingcoveron oneendof the case. Thecasemeasures7long.4wide, and2deep. Onthebottomofthe unit will be fo

4、unda set ofreadings for the BC-950Atransmitterand theyareas follows: R.F.D. 10. Box4116Indianapolis 19,Indiana. Nothingis knownoftheBC-950Atransmitter andsince the testunitwas designed tobeused with theT-23/ARC-5also. it is assumedthat the same readings canalsobeused.Theauthortuned formaximuminposit

5、ionsI.2.3.and-toPosition 5wasusedtotunethe final.tuning foradipin readingwiththeR.F.AMP. TUNINGonthe trans- mitterandforincrease inreadings withthe ANTENNACOUPLING.Later a setofreadings will begiven asusedwith atransmitterinthis locality. Figure Ishows the schematic of the test unit. Thecolor coJing

6、 of the catlle is shown. However, SI1itc!t Position I 2 3 4 5 6 7 Function Osc. G rid Current Ist.H-GGridCurrent Znd.HG G rid Current R-FAmp.Grid Current R-F Amp.Cath.Current Heater Voltage PlateVoltage Operating Ranl:l 4-70 25-90 25-90 20-80 40-55 54 53-55 in ahomebrewunit thecolorcoding need notbe

7、 followed.The connections tothe femaleplug PL-152areshown with the outside ofthe plug facing the viewer. Figure 2 gives the locationofthe test unit in eachpositionofthe test switch. Switch position I finds themeterlocatedin the grid circuitofthe 1625 oscillatorandshunted acrossR:lll:!. In switch pos

8、ition2the meteris in thegrid circuit ofthe 1625.the first harmonic generator, shuntedacrossR:m:,.Inposition3the meteris in the grid circuitofthe832secondharmonic generator. shuntedacrossR:n u.Forposition4 the meter is nowin the grid circuit of the 832 finalamplifier. shuntedacrossR 311.However, inpo

9、sition5 the polarity ofthe meter isre- versed and is now in the cathodeofthe 832 final amplifier.Itis shuntedacrossR:lI:, .andC:I:!I. Forswitch position6themeterisreadingfila- mentvoltage.TheT23 1ARC5 used here hasthe negative sideofthe filament voltage grounded. If.in someinstallations. thepositive

10、 side is grounded.the meterwill notread. Reversing the leads withinthetestunit forposition6should correctthe problem. Position7the meier reads the plate voltage. This takescareofthe Test UnitI-I55-A and a studyofthediagrams willshow thatthe unit u.S. Army SignalCorp, TestUnit 1-155-A withtuning ,tic

11、k. 42CQJanuary, 1965 7 r., .,. -., e! , , - 832 -,I rl-.,o.- R 1625 ,- t-,.-, R.)OI-,1 , .- l625 oee, fig. 2-Test points on the T.23/AR C-5. Numberscorrespond totestswilchpositions. is quite simple. Forthose who plan to build a hornebrew unit: it is fell that precision resistors are not neededalthou

12、gh.if available. should be used. The main thing to remember is that the readings arerelative and will vary according to the transmitter and activity of the crystal used. Tune the grid circuits for maximum readings and use the cathode current position(5)for tuning and loading the final. The following

13、 setofreadings are those that werefoundon theT-23/ARC5transmitter tuned10145.3 me. at theQTHof KN9WEI. SUoPas,Rdg.Sw. Pos.Rdg. I 155 59 2 566 46 3 477 40 4 16 The inside ofthetest unit. fig. 1-eircuil ofIhe lesl unil showingccnnecticnsto PL152plug.The 1 megresistor consish of four 250K .rwott units.

14、Allother resistors are 1 walt 1% .The meier has aninternal resislance of150ohmsandis equivalent10a Weston 301 . C-JJJlCJ . po-!52 - A)30t -. .,. , - . ,. t , s, -(-0 . -. . Test unit in conjunction with theY-231ARC-5. Plate voltageonthe lsI. 1625.400V Platevoltageon the2nd. 1625400V Platevoltageonth

15、e 1st.832390V Plate voltageonthe Final 832.4IOV A newSurplus Conversion Handbookis now available fromCowan Pub- lishing Corp. This new book is50pages larger than the old Command Sets and includes most of the popular Command Set articles in addition toother conversion features. Order your copy soon. January,1965CO43