User's Manual

MDS 05-6399A01, Rev. D MDS Master Station 83
7.5 Testing and Removing an Internal Duplexer
Testing
If you suspect that the internal duplexer is not functioning properly, perform the following steps to deter-
mine if requires replacement:
127. Measure the RF power out of the antenna jack.
 If the power registers approximately +37 dBm (5 watts), the internal duplexer is probably func-
tioning correctly (see
Table 8-1 dBm–Volts–Watts Conversion Chart for dBm-volts-watts
conversion chart).
 If the power registers significantly less than +37 dBm, proceed with Step 2.
2. Locate the TX SMA connection on the front of the duplexer tray.
3. Using an adapter, connect the RF power meter to the SMA Cable on the front of the unit
• If the power registers +39 dBm, the radio board is functioning correctly.
• If the power registers less than +39 dBm, proceed with Step 4.
4. Use the front panel to switch to the alternate transmitter and again measure the RF power output.
• If the alternate transmitter registers +39 dBm, the internal duplexer probably needs replacing.
5. Before replacing the duplexer, verify that the highest or lowest frequencies marked on the duplexer are
the same as radio’s transmit and receive frequencies or within the nominal operating range: 100 kHz
for 400 MHz radios, and 500 kHz for 900 MHz radios.
Removing the Internal Duplexer
To remove the internal duplexer, follow these steps:
1. Disconnect the antenna cables from the back of the chassis.