Specifications

Section-5 Maintenance
October 17, 2013
5‐2
Copyright©2013,HarrisBroadcast
WARNING:Disconnectprimarypower priortoservicing. 888‐2693‐004
SHEET OR RE-MEASURE THE COUPLER WITH A NETWORK ANALYZER TO
DETERMINE THE COUPLING VALUE AT A NEW FREQUENCY.
Note
The caution above does not apply to internal LPU power measurements, which are frequency compen-
sated.
STEP 1
SwitchofftransmitterviaOFFbuttononTCU,LPU,orwebbrowserscreen.
STEP 2 GototheHomescreenandselectBYPASSforLinearandNon‐Linear.
STEP 3 Adjustoutputfiltertonewfrequency.Consultfiltertestdata,specification
sheet,orothermanufacturer‐suppliedinformationfortuningdetails.Donot
attempttoretunefiltersbeforeconsultingwiththefiltermanufacturer.
Note
Some output filters are band limited and may not be adjustable across the VHF band. In cases where the
filters are band limited, a replacement filter will be required.
Warning
HARRIS DOES NOT RECOMMEND FIELD TUNING OF FILTERS. CONSULT THE
MANUFACTURER OF THE FILTER BEFORE ATTEMPTING ANY FREQUENCY TUN
-
ING OF FILTERS. HARRIS RECOMMENDS ACQUIRING A FILTER TUNED TO THE
FREQUENCY
OF CHANGE BEFORE PROCEEDING WITH A FREQUENCY CHANGE.
STEP 4
AdjustLPUtonewfrequencyinSETUP>PFRU>CENTERFREQUENCY
submenuofLCDscreen(changewholenumberandthenuseoffsetto
changedecimal)oruseEXCITERHOME>SETUP>PRFU>CHANNELSETUP
webbrowserscreen.Example:ifthedesiredfrequencyis500.75,MHzenter
’500.75’.(wholenu
mberwithoffsetchangeisnotrequired)
STEP 5 OndualLPUmodels,holdtheTCUPowerLowerbuttondownfor20‐25
secondstoreduceoutputpoweratturnon.IfaTCUisnotpresentthepower
canbeloweredinthesamewayusingtheLPUPowerLowerbuttonor
anotheralternativeisuseoftheLPULC
DSETUP>XMTRPOWERSETTINGS>
FWDPWRREFandsetthevaluetoapproximately10%ofdesirednominal
TPO.
STEP 6 OndualLPUmodels,navigatetotheTCUHome>Service>Configscreenand
setthenewpowerwarningvalues(ifdifferentthanprevioussetting).For
singleLPUsystemsusetheLCDtonavigatetoSetup>XMTRPOWER
SETTINGSscreen,andenternewpowerwarningandfaultvalues(ifd
ifferent
thanprevioussetting).Or,ifusingtheLPUwebbrowserinterfacescreens
navigatetoUAXHome>Service>Configscreenandenterdesiredwarning
andfaultlevelsasneeded.
STEP 7 Switchtransmitterbackon.OndualLPUmodels,thisisdonebypressingthe
TCUONbutton.OnsingleLPUmodels,thetransmitterisswitchedonby
pressingtheLPUONbutton.
STEP 8 Useacalibrated,averagingpowerwattmeterandadirectionalcoupler(with
knowncouplingfactor)tomeasureandmonitorthetransmitteroutput
power.
STEP 9 Ifthisisafrequencythathasnotbeenusedpreviously,performasystem
powercalibrationasoutlinedin"5.4Dig
italPowerCalibrations"onpage5‐5
or"5.6AnalogPo
werCalibrations"onpage5‐19.Ifthefrequencyhasbeen
usedpr
eviouslyreferto5.3.1.1StoredCalibrationSets.Calibrationisnot
requiredfo
rpreviouslyusedfrequenciesaslongastheoperationalpower
levelremainsthesame.