Specifications

Section-5 Maintenance
November 11, 2013
5‐22
Copyright©2013,HarrisBroadcast
WARNING:Disconnectprimarypowerpriortoservicing. 888‐2628‐300
Figure 5-13 System Coupler
5.10.1.1 CalibrateForwardTotalPower
STEP 1 Calibratetheaveragingpowermeterfollowingmanufacturersinstructions.
STEP 2 Setthemeteroffsettothevalueprintedonthecoupler,orassuppliedwithadata
sheetincludedwiththefactorytestdata.
STEP 3 Removethesamplecablefromthesystemforwarddirectionalcoupler(afterfilter)to
becalibrated(seeFigure5‐13).
STEP 4 Connectthepowermeterprobetothesystemforwarddirectionalcouplerport.
Couplerdesignsliketheoneshownin
Figure5‐13musthave50ohmterminationson
theportoppositethemeasurementport.Thepowermeterprobemustbesupported
topreventdamagetoconnectors.
STEP 5 PressandholdthepowerLOWERbuttonfor40secondsornavigatetoOutputscreen
andsetCab.Ref .Pwr.tozero.Eitherofthesestepswi llinsurethatthetransmitter
doesnotproducelargeamountsofRFpoweratturnon.
STEP 6 Turnontransmitterandwhilemonitoringcabinetreflectedpower,slowlyadjustthe
Maxivadigitaltransmitteroutputuptolicensednominalpower(asprogrammedin
theSystemSetupscreen).Ifhighlevelsofcabinetreflectedpowerarenoted,stop
raisingpower,abadload,transmissionlineconnection,orantennaisindicated.
STEP 7 Allowthetransmittertorunforseveralminutesatnominalpowertogivethe
amplifierstimetowarmupandstabilize.
STEP 8 PressthemanualbuttonontheTCUandholditinfor5seconds.
STEP 9 Re‐adjustthetransmitterpoweroutputasrequiredtoreachlicensednominalpower.
Besureitisstable.
STEP 10 Disconnectthepowermeterprobefromtheforwardcouplerportthenreconnect
forwardsamplecable.
Note
The detector voltage values are provided on the Sys Pwr Calibrate screen shown in Figure 5-14. They are
listed in the column to the right labelled Detector. The Sys Fwd (kW) detector voltage level should be
between 3.0 and 3.2V at full rated power. Operating in this range insures accuracy (detector’s linear
region). If the detected levels are too high, attenuation must be added at the coupler port to reduce the
detected voltage level.
STEP 11 AccesstheCalibrationscreenbynavigatingtoSystem>SystemService>System
Setup>SystemPowerCalibrateasshownin
Figure5‐14.
Coupler
Reflected
Forward
Coupler