Nautel XR6, Operation And Maintenance Manual

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XR6/XR3 Operations and Maintenance Manual Test and adjustment
Page 5-2 Issue 3.1 2013-03-14
3. Connect the XR6/XR3's RF output to a precision 50
Ω
dummy load that is able to
accurately display the RF power being applied to it.
4. Simulate the closing of all external interlocks. This requires a short circuit between TB1-1
and TB1-2 of the remote interface PWB. Ensure all networks connected to the transmitter’s
RF output are properly covered.
5. Switch on the ac power at the service entrance to turn on the transmitter.
6. Select
Control - Local
control.
7. Disable the RF power stage by pressing
Control - RF Off
.
Standard adjustments
Complete the following standard adjustments when the XR6/XR3 transmitter’s operation has been
established:
• Modulation checks
Modulation checks
Verify that the RF output is appropriately modulated when audio is applied:
1. Connect an appropriate modulation monitor to the remote interface PWB
RF MONITOR
connector (J8). The modulation monitor should have an impedance of 50
Ω
to obtain
accurate readings. If the remote interface PWB’s
BYPASS/GAIN
switch (S2) is set to
BYPASS
,
the
RF MONITOR
output is a nominal 1 V rms. If the remote interface PWB’s
BYPASS/GAIN
switch (S2) is set to
GAIN
, the
RF MONITOR
output can be up to a nominal 5 V rms.
2. Verify that forward power is selected for display on the
RF KILOWATTS
meter.
WARNING:
If a jumper is placed between interlock inputs TB1-1/TB1-2 on the
remote interface board, safety features controlled by the external
interlocks will be disabled. A fail safe method of alerting personnel to
this fact should be implemented. Voltages which are dangerous to life
will be present on the RF output stages and the antenna system if the
transmitter is turned on.