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HARRIS
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WARNING: Disconnect and lockout AC primary power prior to servicing
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2.17.3 Aural Power Calibration
2.17.3.1 System Forward Power
Some of the power calibrations are based on forward power, calibrate it first.
STEP 1:
Using the precision coupler in the RF system and the precision power
meter to establish the output power.
STEP 2:
Verify the RF level at the board input, the signal should be between 40 to
60 mW. Connect the cable back to the control board.
STEP 3:
Go to the system service screen and using the pull-down keyboard. enter
in the reading from the power meter.
2.17.3.2 Reflected Power
This would follow forward power calibration.
STEP 1:
Remove the cable from the reflected sample controller input, Rotate the
reflected sample element to couple with forward power.
STEP 2:
Verify the RF level, 40 to 60mW.
STEP 3:
Connect the 20 dB pad to the reflected input, connect the cable to the pad.
STEP 4:
Use the service screen to calibrate the reflected power metering to read
one percent of the forward power.
STEP 5:
Remove the pad and reconnect the cable.
2.17.3.3 PA Cabinet Power Calibration
The sample elements have coupling ratios marked on the element. These can be used as
offset inputs to the power meter. The slave controller calibrate pot is adjusted for 3 volts
at the peak detector test point. Next use the PA service button to access and set the PA
power levels.
2.17.3.4 Two Cabinet Reject Load
The power in the reject load is half of a single cabinet with perfect hybrids. If the level
measured at the top of the control cabinet is in the 40 to 60 mW range, calibrate the
reject load to be 80 percent of the reject load rating.