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1 HP Archive This vintage Hewlett Packard document was preserved and distributed by www. Please visit us on the web ! On-line curator: Daniel Sheen }l~"-",.:"""'. #jJSTANDINGWAVEINUICATOR(1-lr9 OPERATINGANDSERVICINGMANUALFORMODEL415 BSTANDINGWAVEINDICATORSERIAL4183 ANDABOVE(I,;..~'.tCopyrightHEwLETT-PACKA RDCOMPANY1955275 PAGEMILLROAD,PALOALTO,CALIFORNIA, FREQUENCY:SENSITIVITY:NOISELEVEL:AMPLIFI ERQ:CALIBRATION:RANGE:SCALESELECTOR:.MET ERSCALES:GAINCONTROL:INPUT:RECORDEROUTPU T:lNPUTCONNECTOR:POWER:DIMENSDNS:WEIGHT: ACCESSORIESFURNISHED:i\.CCESSORIESAVAILA BLE:SPECIFICATIONS1000cps 2%. } ~ , db."Normal"~"Expand"~and"-5db".SWR1-4~SW R3-10, ,db0-10, "Bolo"(200ohms).))

2 ; "Crystal".200ohmsforcrystalrectifier."20 0,000ohms". rnafullscaledeflec-tion~ 10%~60cps, :7-1/2"wide~11-1/2"high,12-1/4" :19"Wide,7"high,11-3/4" :Net13 Ibs.~ :Net18 Ibs., ,44inchesofRG-58/U50ohmcoaxialcabletermi natedatoneendonlywithaUG-88 ,4feetofRG-58/U50ohmcoaxialcableterminat edateachendwithUG-88 1-1 INTRODUCTORYI nhighfrequencyapplications,standing-wave mea-surementsarethecustomarymeansofinves tigatingtheimpedancematchoftransmissions ystems,varioustypesofterminationssuchasa ntennasandloads,andoth21'high-frequencyd evicessuchasconnectors,transitions, ,fixed-frequencyelectronicmetercalibrate dtoindicatedirectlybothvoltageandpowerst anding-waveratioswhenusedwithsquarelawde tectorssuchascrystaldiode!

3 " , ,abarret-tel' ,thecorrectbiascurrentisautomaticallysup pliedthroughtheinputjack, , , , 3 ELECTRICALCHARACTERISTICSTheModel415 BStandingWaveIndicatorisdesignedandcalib ratedtomeasureasignal-obtainedfromsquare -lawdevicessuchascrystaldiodes(atlowsign allevels)andbarretters;however, (whensetforCRYSTALorBOLO operation) dbsothatreadingsnormallyreadfroma ,or200,000ohmsasselectedbytheBOLO-CRYSTA L-200, , 2% 1milliampererecorder(orotherindicatingde vice) , 1ampere"Slo-Blo" 4 APPLICATIONSThe<tiJModel415 BStandingWaveIndicatorhasbeenspecificall ydesignedforusewiththe!5f; wsthevariousHewlett-Packardinstrumentsfo rtheseservicesarrangedbyfrequencycoverag e.

4 ~-SLon~tINE--. @1@+tTI@ @ @U .,. <t) \+--CRYSTALDETECTORP421 ,TYPE'N'SYSTEM\..)IIl<J440 ADETECTORMOUNT,422 BBROADBANDPROBE., <JFORWAVEGUIDESLOnED~ <tiJMicrowaveEquipmentforSlottedLineMeas urementarrangedbyfrequencyrange 2-1 INTRODUCTIONT hissectioncontainscompleteoperatinginstr uctionsfortheModel415 BStandingWaveIndicator,testset-upinstruc tions, ,considerableattentionshouldbegiventothe variousmeasurementdiscussions,LowVSWR,Hi ghVSWR,PrecautionswithDetectors, :2-2 Installation2-3 RequiredSignalSource2-4 Measurements2-5 HowtoOperatetheModel415B2-6 PrecautionswhenusingCrystalDetectors2-7 DetectorProbePenetration2-8 PrecautionswithSignalSources2-9 HighVSWR's2-10 LowVSWR's2-11 ImpedanceMeasurementRules2-12 ImpedanceMeasurementProcedure2-13 ImpedanceMeasurementandtheSmithChart2-14 ProcedureforSmithChartCalculations2-2 INSTALLATIONThe415 BStandingWaveIndicatorhasbeenrigidlytest edandinspectedbeforebeings~ , found,followtheprocedureoutlinedinthe"Cl aimforDamageinShipment" ,orintherack-mountingmodel.

5 , (whichareincapableofsinusoidalampli-tude modulationwithoutseriousfrequencymodulat ion)itiscommonpracticetokeythemodulating electrodeoftheklystronfromasquare-wavege neratortoob-tain100% (tothefrequencyofthe415B). ,caremustbetakenthatthe415 Bisnotoverloaded,,.,em" ,thedutycycleshouldbenotlessthanapproxim ately40%.Sincethe415 Binputinthe200nCRYSTAL positionisthroughatransformer, , , , ,undercertaincondition:;;, ,alongwithtechniquesforminimizingthem, ~ ,particularlyindesignanddevelopment,wher eagreaterknowledgeoftheloadisrequired,an dthiscanbeobtainedbymeasuringtheposition oftheminimuminthestanding-wavepattern(pr obecar-riagesareusuallyequippedwithanacc uratescaleandindicatorforthispurpose).

6 Theminimumisusuallynotuseddirectly,butis comparedtothepositionoftheminimumwhensom eknownload(for :NIR,1db,1 VSWR expandedand1 )(tl(" :::~Jii(tl~ "~:~'",',-4'-:.'..,'.:".'-M:1:..\"',:.~. GAINRECORDER ({Q)~ ~edscales,normalscales,orshiftmeterdown- scaleby5decibels.,".j':-,,'.."::~'.,;'.: :~:~;' !200n200n-200 Knr::;\ "~j:.,:"r:;.~'.. , , ) , , , , , ) (solidpointerlineinFigure2-3), )Ifthereadingattheminimumislowerthan3ont heuppermostscale(dashedpointerlineAinFig ure2-3),settheSWR-DBRANGE switchtothenextrangeandreadtheindication onthesecondvswr(3to10) (dashedpointerlineB). (B);, )IftheSWR-DBRANGE switchhastobechangedbytworangesthescales hiftstwice,backtothetopscaleagain;howeve r, ) XPAND,themeterpointerwill"pin"downscalea ndmustberesettofull-scalebyincreasingthe metersensitivityusingtheGAINcon- ) ' "tip-ringsleeve" ; , , , ,theshiftinthemaximaandminimawillnotbeeq ual, 7 DETECTORPROBEPENETRATIONA generalruleinslottedlineworkisthatthepen e-trationofasamplingprobeintothelineshou ldbeheldtoa , ,ifnecessary,toagainobtainafull-scalerea dingW' , (smallpenetration) , ,omthatontheattenuataI'ofthesignalgenera tor, ,adjustthedetectortoobtainafull-scalerea dingonthe30db-rangeofthestandingwaveindi cator(GAIN controlsettomaximum).}

7 'Themeteronthestanding-waveindi-catorsho uldagainreadfull-scale, (SWR)4!/Ii/I11/IJ/II/!/-~.I/I/-J!I/IiiV! % , , ~sa fewmicro-watts,orwhenareadingoffullscale onthe30-dbrangeofthestandingwaveindicato rwiththeGAIN controlsettomaximumisobtained. ' , , , , ,say,15%secondharmoniccontent, , , (seeparagraph2-9,"HighVSWR's",forexample ofthisformofmeasurement). ,theminimumshouldbedefinitelysmall(highv swr) ,locationoftheminimumina , , ,frequencymodulation, ,for,unlessveryslight, ~ ~owCDo0 ~I,k-A,,III,'I" ,. (A)FreeofFM(B)WithModerateFM=-========== =======-,-----, , 'mea-suringnominalvswr's uptotherangeof10-12,butathighervswr' , , ,thereisdangeroftheerrorcausedbya changeindetectorcharacteristicsasther-fe nergyincreasestoa muchhigherleveLThereisavailableformeasur inghighvswr's amethodthatisaccuratewithinapproximately 1% (SeeFigure2-7) (d1- d2)WhereAListheguidewavelengthinemandd1a ndd2arethelocationsofthetwotwice-minimum points, ,orifalinearreceiverisused, , , ,theminimumshouldbedefin-itelysmall(high vswr).

8 ,..IZEml"aloa::A.!; ~E_~ "ETE~SPROBEPOSITIONhVSWR=."( IX)2 10 LOWVSWR' , ,thesereflectionsareagainreflected, ,thephaseofthereflectionsischanged, ,itonlybecomesimportantwhenmea-suringlow vswr'sintheorderof2orless, ,ofcourse, ,whenthevswrislow, , , :Theshiftintheminimumwhentheloadisshorte disnevermorethan , , , ,theloadiscom-pletelyresistiveandhasaval ueofZox , '.GENERATORIFMINIMUMSHIFTS>"'/4, VSWRLOADMINIMUM:/MINIMUMWILLSHIFTTO~VMIN IMUMWILLSHIFTTO~THISREGIONIFLOADTHISREGI ONIFLOADISINDUCTIVE\SCAPACITIVEILOAD+~4 IFMINIMUMDOESNOTSHIFT, ! ( +-SHORT04-LOADAnd: Ad==Shiftincentimetersoftheminimump:> zLWhere:XA"21 -j(VSWR)TanX(VSWH)-iTanX~dtakesapositive (+)signwhentheminimumshiftstowardtheload .)

9 ~dtakesanegative(-) ,oneofthemostindispensabletoolsandcer-ta inlythesimplesttouse, * , , , *Smith, "Transmission-lineCalculator"Electronics , , , , ,1948, + ,- jX .~Forexample,theimpedancepointofalineter minatedbyitscharacteristicimpedancewould bethecenterofthechart( ).Inanotherexampleofactualimpedancecalcu lation:ZL=5+j25ohmsNormalizedfora50ohmli newouldbe:zN= + , (. \).. (eithertowardtheloadortowardthegenerator )whentheloadwasreplacedbyashorttothequan tity. \ ,theSmithChartwouldbeenteredwithA.\ , ,thewavelengthofthelineis30em(AL) (towardgenerator).(. ld=22-19= (.\L). \3 ld(theshiftincentimetersoftheminimumpoin twiththeshortapplied). + '''' , (.))

10 ,0?.;,;~..~~ ~0?..0.;i::f';:>.. ,A(l~I,~~II1\IINPUTIlVSWR\INPUT-115 DBMETERTRANSFORMERSELECTIVECbAMPLIFIER(3 00 BGAIN)AMPLIFIERVIV2V3 POWERSUPPLYPOWER115/230 VACTRANSFORMERRECTIFIERSERIESTUBE+240 VDC-TIV 4V 6 REFERENCETUBEV7 CHASSISGROUNDF igure3-1,Mode1415 BBlockDiagram(J) 'dPJaq11lo;',~.~~= 1 CIRCUITDESCRIPTIONTheModel415 BStandingWaveIndicatorconsistsofahigh-ga inamplifier,a 1000cycleresonantcir-cuit, , , , + :1step-upinputtransformerT2, , ,barretterorarelativelyhigh-impedancedev ice(bridgecircuit,etc.). ;exceptthattheprimarywindingisnowreturne dtoacur-rentsource,R2andR3,providingd-co peratingbiasthroughthetransformerwinding toany200ohmdetectorelementconnectedtothe inputjack~TheHIGH-LOWtoggleswitchshuntst hecurrentsourcewithRIsothattwodifferentv aluesofbias( ) ,S5, ,toobtainsquarelawmetercalibration, ,VIA, , , (GAIN controlR22 AandB) ,oneprovidingapproximately25db( dbonthemeterscale)ofcontrolforcoarseadju stments, db( ))