Specifications

Section-5 Maintenance
November 11, 2013
5‐24
Copyright©2013,HarrisBroadcast
WARNING:Disconnectprimarypowerpriortoservicing. 888‐2628‐300
Figure 5-15 Cabinet Coupler
5.10.2 ReflectedPowerCalibration
ThisprocedureestablishesthevaluesusedtocalculatetheVSWRprotectionthresholdsforfoldbackandfault
events.Thesevaluesarebasedonthe"FwdPwrOut(W)"valueenteredintotheSystemSetupscreenin
Figure3‐25
onpage3‐22.
• Thefoldbackpowerlevel(basedonsystempower)canbesetbynavigatingtoSystem>SystemService>Sys‐
temSetup>SystemThresholdtodisplaytheThresholdSettingscreen.TheFoldbackPwrlevelinWcanbe
enteredthere.Themaximumvalueallowedis2.78%oftheSystemPwrOut(W)valueonthe
SystemSetup
screen.The2.78%reflectedpowerlevelisequivalenttoa1.4:1VSWR.
• Thesystemfaultthresholdlevel(basedonsystemreflectedpowerlevel)canbesetbytheuser.Settingthe
faultthresholdlev elisdonebyenteringatripvoltagelevelintheRfldPwrwindowontheSystemThreshold
screen.Thevoltageenteredhereshouldcorrespondto100mVlessthanthe
detectedvoltagelevelindicated
whencalibratingsystemreflectedpowerasdescribedinSection5.10.2.1,CalibrateSystemReflectedPower,
onpage5‐24
• ThecabinetfaultthresholdissettoaVSWR=1.9:1atthefactoryandisnotadjustablebytheuser.A 1.9:1
VSWRcorrespondsto9.63% reflectedpower.
5.10.2.1 CalibrateSystemReflectedPower
Note
Before attempting reflected calibration forward calibration must be confirmed.
STEP 1 Turnonandadjusttransmitteroutputtolicensedaveragepowerasmeasuredwith
anaveragingpowermeter.
STEP 2 PressSystem>SystemService>SystemSetup>SystemPowerCalibratetoviewthe
SystemGUIscreenshownin
Figure5‐14onpage5‐23.
STEP 3 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awa yfromthe
calibrationscreenwillalsoreactivateVSWRprotection.
STEP 4 Removethesamplecablefromthesystemreflecteddirectionalcoupler.Ifthereare
attenuatorsonthereflectedcouplerport,keepthemwiththereflectedsample
cable.
Forward
Coupler
Coupler
Reflected