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HARRIS
888-9058-001
WARNING: Disconnect and lockout AC primary power prior to servicing
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STEP 14:
Switch AGC back ON when done and RAISE power to 100%.
NOTE:
Refer to AGC adjustments if needed.
2.17 Power Calibration
2.17.1 Basics of Power Calibration.
Power calibration is based on the use of a RF average power meter such as those
manufactured by Agilent. Study the power meter manual for calibration and the use of
offsets. The Analog to Digital conversion input is limited to about four volts. The system
and other metering in the control cabinet requires an RF level at the board input of about 40
to 60 mW for 3 volts of metering. This allows for some over-range and still have sufficient
level or resolution of smaller voltages.
The RF metering input to the PA Cabinet slave controller has more latitude as there is a
range adjustment control for each of the RF detectors. This allows the full scale RF level
range to be set to three volts at the peak detector test point. Further calibration will be done
through the GUI service screen.
2.17.2 Visual Power Calibration
2.17.2.1 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.
2.17.2.2 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.
