Specifications

Section-5 Maintenance
November 11, 2013
5‐18
Copyright©2013,HarrisBroadcast
WARNING:Disconnectprimarypowerpriortoservicing. 888‐2628‐300
5.9.3.1 CalibrateSystemReflectedPower
Note
Before attempting reflected calibration forward (visual and aural) calibration must be confirmed.
STEP 1 Turnonandadjusttransmitterto100%ratedvisualpeakpowerasmeasuredwithan
averagingpowermeter.
STEP 2 .Setvideoinputsignalto50%flatfield(gray)andturnsoundcarrieron.
STEP 3 PressSystem>SystemService>SystemSetup>SystemCalibratetoviewtheGUIscreen
showninFigure5‐9onpage5‐15.
STEP 4 PressdisableVSWR.ThisdisablesVSWRprotectionfor5minutes.Ifreflected
calibrationisnotfinishedwithin5minutesthetransmitterwillfaultoffandwillneedto
berestartedbeforerepeatingthereflectedcalibration.Navigatingawayfromthe
calibrationscreenwillalsoreactivateVSWRprotection.
STEP 5 Removethesamplecablefromthesystemreflecteddirectionalcoupler(seeFigure5‐
8,above).Ifthereareattenuatorsonthereflectedcouplerportkeepthemwiththe
reflectedsamplecable.
STEP 6 Attacha10dBattenuatortothereflectedsamplecable(alongwithexisting
attenuators).
STEP 7 Removethe50ohmterminatorfromtheoppositecouplerportandplaceitonthe
reflectedport.
STEP 8 Placethereflectedcable(with10dBpadontheportwheretheterminatorwas
removed.Thisessentiallyattachesthereflectedcable(with10dBpad)toaforward
sample.
Note
The detector level (at licensed output power) should be between 2-3 V when the reflected cable is attached
to a forward port with a 10 dB pad. If the reflected detector voltage is too high, additional pads must be
added to get the voltage in the 2-3 V range. The added pads will stay with the reflected cable when it is
moved back to the reflected port later in the procedure. The 10 dB pad will be removed when the reflected
cable is placed back on the reflected port.
STEP 9 ClickonthecorrespondingwindowforSysRefldpower,openingan umericentrybox.
STEP 10 Enterthevaluethatis10%oflicensednominaloutputpower.
STEP 11 ClickonDONEtostorethechanges,orCANCELtoignoreallchangesmade.Record
thereflecteddetectorvoltageforlateruseinsettingthereflectedpowerthreshold.
Note
Refer to "3.9.3.1.2 System Thresholds" on page 3-24 to get information on setting the system reflected
threshold level. This level must be set before testing the VSWR protection (reflected power trip point). The
reflected trip level should be set to the voltage level recorded in the previous step minus 100 mV.
STEP 12 VerifytheVSWRprotectionbypressingtheEnableVSWRbuttonontheCALIBRATE
screen.Thetransmittershouldfaultoff.
STEP 13 Removetheterminatorfromthereflectedportandplaceitontheforwardport.
STEP 14 Removethe10dBattenuatorfromthereflectedcable.
STEP 15 Returnthereflectedcabletothereflectedport.
STEP 16 Turnonthetransmitter.Itshouldcomeuptolicensednominaloutputpower.
STEP 17 Endofprocedure.
5.9.3.2 CalibrateCabinetReflectedPower
Cabinetreflectedpowerisnormallycalibratedatthefactoryduringfinaltestanditmaynotneedtobecalibratedin
thefield.ThecabinetreflectedtrippointhasbeensetatthefactoryandisnotaccessibleviatheGUI.Should
recalibrationofcabinetreflectedpowerberequired,anddetector
voltagesaresignificantlychangedforsome
reason,thecabinetreflectedtriplevelcanonlybeadjustedthroughuseofaterminalemulatorprogramlike
Terater m.ContactHarrisserviceifthisisneeded.