Nautel XR6, Operation And Maintenance Manual

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XR6/XR3 Operations and Maintenance Manual Test and adjustment
Issue 3.1 2013-03-14 Page 5-3
3. Select the highest preset RF power level and verify that the RF output, displayed on the
RF
KILOWATTS
meter, is the desired forward power level.
4. Verify that an audio signal generator is connected between TB2-1 (+) and TB2-3 (-) on the
remote interface PWB, and that its output is preset to 1,000 Hz at a zero output level (turned
off).
5. Turn on the audio signal generator and increase the output level of the audio signal generator
until a modulation depth of 100% is attained, as indicated on the modulation monitor. The
audio signal generator's output level should be +10 dBm.
6. Verify that the RF output's modulation envelope is acceptable.
7. If the program audio can be set to +10 dBm when 100% modulation is required, it is
recommended the
AUDIO GAIN
potentiometer on the interphase PDM driver PWBs be left
at the factory setting.
8. If the program audio cannot be set to +10 dBm when 100% modulation is required, the
AUDIO GAIN
potentiometer on the remote interface PWB must be reset as follows:
– Determine the program audio level (in dBm) that will be applied when 100% modulation
is expected. (It must be between 0 dBm and +12 dBm.)
– Set the audio signal generator's output to the level that will be applied by the program
audio when 100% modulation is expected.
– Adjust the
AUDIO GAIN
potentiometer on the remote interface PWB for 100%
modulation, as indicated on the modulation monitor.
9. Set the output level of the audio signal generator to zero (turned off).
10. Turn off the RF power stage: press and release the
Control - RF Off
switch. The
Control - RF
Off
lamp will turn on and the
Control - RF On
lamp will turn off.
11. Disconnect the audio signal generator from TB2-1 (+) and TB2-3 (-) on the remote interface
PWB.