Nautel XR12 Operation And Maintenance Manual

Also see for XR12: Installation manual Troubleshooting manual Preinstallation manual

XR12 Operations and Maintenance Manual Test and adjustmentPage 5-2 Issue 3.1 2013-03-143. Connect the XR12's RF output to a precision 50 Ω dummy load that is able to accuratelydisplay the RF power being applied to it.4. Simulate the closing of all external interlocks. This requires a short circuit between TB1-1and TB1-2 of the remote interface PWB. Ensure all networks connected to the transmitter’sRF 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 adjustmentsComplete the following standard adjustments when the XR12 transmitter’s operation has beenestablished:• Modulation checksModulation checksVerify that the RF output is appropriately modulated when audio is applied:1. Connect an appropriate modulation monitor to the remote interface PWB RF MONITORconnector (J8). The modulation monitor should have an impedance of 50 Ω to obtainaccurate 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/GAINswitch (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 theremote interface board, safety features controlled by the externalinterlocks will be disabled. A fail safe method of alerting personnel tothis fact should be implemented. Voltages which are dangerous to lifewill be present on the RF output stages and the antenna system if thetransmitter is turned on.