Specifications

Maxiva ULX Series
November 11, 2013
5‐11
888‐2628‐300 WARNING:Disconnectprimarypowerpriortoservicing.
Copyright©2013,HarrisBroadcast
5.8 ALCVoltageAdjustment
ThecabinetALCvoltageisdisplayedontheOutputscreenasshowninFigure5‐7.AtfullTPO(andthoroughly
warmedup)theALCvoltageshould beinthe3.2to3.6Vrange(closerto3.6Vismoredesirable).ALCvoltageis
usedtoadjusttheelectronicattenuatorinthePDUtoraiseorlowerpower.AsthePAmodulesheatuptheirgain
decreasesandwhileinAuto
modetheALCvoltagewillincreaseautomaticallytokeeppoweroutputstable.ALC
voltagehasamaximumvalueof4V.Oncethe4Vlevelisreachedfurtherincreasesinpoweroutputarenotpossible.
Figure 5-7 Output Screen
5.8.1 ALCVoltageAdjustmentProcedure
Note
The following procedure assumes that the transmitter cabinet has been previously calibrated and operat-
ing normally. The cabinet power calibrations are performed during final test at the Harris factory.
STEP 1 T ransmittershouldbeconnectedtoaknowngoodtestloadorantennasystem
capableofhandlingthefulltransmitterpower.
STEP 2 AdjusttransmitteroutputtodesiredoperationalTPOwithpowercontrolsettoAuto.
STEP 3 Allowtransmittertowarmupfor30minutes.
STEP 4 NavigatetotheOutputscreenandcheckALCvoltagelevel.
STEP 5 IfALCvoltagelevelisbelow3.2Vorabove3.6Vproceedwiththefollowingsteps.
STEP 6 TurntransmitterOff.
STEP 7 LowerALCvoltagebydecreasingattenuatorAT8.RaiseALCvoltagebyincreasingAT8.
AT8islocatedattheinputtothePDUsplitterwhichislocatedjustbehindthePDU
modules.ItcanbeaccessedbyopeningthereardoorandlookingbehindthePDU
modules.
STEP 8 ChangeAT8upordownin1dBincrements.
Caution
AVOID MAKING LARGE CHANGES TO AT8 WHICH MAY CAUSE DAMAGING
POWER OVERSHOOTS. MAKE THE CHANGES INCREMENTALLY IN 1 DB
STEPS.
STEP 9 TurntransmitterOnandallowpowertoachievenominallevel.
STEP 10 Repeatsteps6to10untilALCfallsintothe3.2‐3.6Vrange.
STEP 11 SwitchtotheotherPDUandcheckALClevel.Itwilllikelyproduceaslightlyhigheror
lowerALCvalue.Aslongasitfallswithinthe3.2‐3.6Vrangethatisacceptable.Ifitis
slightlyabovethe3.6Vrangethatisacceptableaswell,aslongas
thetransmitterhas
enoughheadroomtoreachfulloperatingpowerunderhotconditions.
STEP 12 EndofProcedure.
ALC
Voltage