Specifications

Section-5 Maintenance
October 17, 2013
5‐28
Copyright©2013,HarrisBroadcast
WARNING:Disconnectprimarypower priortoservicing. 888‐2693‐004
5.6.3.1 AnalogSystemReflectedCalProcedure
Priortosystemreflectedpowercalibration,forwardpowercalibrationmustbeperformedorconfirmed.
STEP 1
ZeroandcalibratetheRMSpowermeter,followingthemanufacturer’s
proceduresforspecificmodelbeingused.
Note
The power meter reads average power. Conversion to peak visual power is required. See Section 5.6.1 on
page 5-21 for methodology.
STEP 2
Locatethesystemforwardcalibrationsample,whichshouldhavebeen
measuredandlabeledatthefactorywiththecouplingfactorforyour
frequencyofoperation.Thiswilleitherbeaforwardportonthepre‐filter
directionalcouplerwhichisleftavailableforthispurposeinastandalone
(i.e.non‐ra
cked)configuration,orthefrontbulkheadPREFILTERforward
powersampleinarackedconfiguration.Ifthecouplingfactorisinquestion,
orifthefrequencyhaschanged,theapplicableforwardcouplerportshould
besweptwithanetworkanalyzertodeterminethenewcouplingvalue.
Pleaseremembertoincludethesampl
ecableswhencharacterizingthe
bulkheadmeasurementpoint.
STEP 3 Oncethecouplingvalueisdetermined,enterthisvalueasanoffsetinyour
powermeter,setthemeter’sdisplaytoreadindBm(3digitsissufficient,i.e.
xx.xdBm),andconnectthemeter’ssensortothisport.
Note
Be certain that the sample level present at this point (max system output, in dBm, minus the coupling fac-
tor) does not exceed the maximum input range of your particular
power sensor.
STEP 4
Connectthevideosourcetothevideoinputofthetransmitter.Setvideo
sourcetoblackpicturewithzerosetup.
STEP 5 IfdualLPUsareinusesettheTCUDriverControltoManual.SelecttheLPU
tobecalibratedastheactiveLPU.
STEP 6 PressandholdtheLowerbuttonfor30secondstoreducetransmitterRF
outputatturn‐on.UsetheTCULowerbuttonfordualsystems.UsetheLPU
LowerbuttonifasingleLPUispresent.
STEP 7 TurntransmitteronbypressingtheOnbutton.UsetheTCUOnbuttonfor
dualsystems.UsetheLPUOnbuttonifasingleLPUisinuse.
STEP 8 SetbothlinearandnonlinearRTACtoBypass.ThisisdoneviatheLPUfront
panelLCDorviatheLPUGUIscreenshowninFigure5‐14onpage5‐23.
STEP 9 Switchoffthesoundcarrier.ThisisdoneonAnalogSetupscreen3shownin
Figure5‐15onpage5‐24.
STEP 10 RaisetransmitterpoweroutputtoratedforwardpowerbypressingtheRaise
buttonwhilemonitoringthepowerlevelonthepowermeter.
STEP 11 Setsynclevelto100%whileatratedoutputpower.Thisisdonebyincreasing
ordecreasingtheSyncLevelOffsetonAnalogSetupscreen1shownin
Figure5‐15onpage5‐24.Thepow
eroutputwillneedtoberesetto100%
afterthesy
nclevelisadjusted.Thismaytakemultiplestepstogetproper
synclevelatfullpowerlevel.
STEP 12 Enterthereflectedpowercalibrationmenu,eitherfromthefrontpanel
(Setup>XMTRPOWERSETTINGS>POWERCAL>REFLECTED)orfromthe
WebGUI.See’SystemCali bration’(leftside)Figure5‐13onpa
ge5‐23
STEP 13 Lowpointcali bration:RemovetheFWDandRFLDsamplecablesfromthe
activeLPU(thecablesarelabeledFWDandRFLDontheirrespectiveheat
shrink,forreferencewhenreconnectingthem.)Ifdesired,youmayusea
powermetertomeasurethelevelpresentontheFWDsamplecableand
verifytha
titisapproximately0dBm.ConnecttheFWDsamplecable,
througha20dBattenuatorpad,totheREFPwrinput.PressSavetostorethe
valueandproceedtothehighpointcalibration.RefertoFigure5‐17onpage
5‐29.