5.9.4.7.1 How To Verify VHF Duplexer Isolation
5.9.4.7.1 How To Verify VHF Duplexer Isolation
Procedure Steps
1
Connect test equipment as shown in
2
Observe and note the level in dBm as shown on the service monitor.
3
Connect the test equipment to the duplexer as shown in
4
Observe and note the level in dBm as shown on the service monitor. (If no number is displayed, consider
isolation to be greater than 105 dB, which exceeds the specification.)
5
Subtract the absolute number noted in step 4 from the number noted in step 2. The difference should be
less than 75 dB to meet specification for Isolation.
6
Repeat steps 1 through 5 for Low-Pass/High-Notch cavities with the following exceptions:
a. Set service monitor tor Rx or Tx frequency, whichever is
HIGHER
b. Connect service monitor to Low Pass duplexer input (cavity #1)
c. Connect terminator to cavity #6.
5.9.4.8 VHF Duplexer Post Tuning Checks
Procedure Steps
1
Make sure all locking screws are tight. Re-install dust covers on all trimmer capacitors.
2
Make sure all tuning rod locking screws (6) are tight.
5.9.5 Tuning a UHF Duplexer
The following procedures are most easily performed with the duplexer module removed from the rack or cabinet. Be
sure to make note of the transmit and receive frequencies for the particular base radio before beginning.
If the duplexer module is tuned according to instructions and does not meet specifications for return loss, insertion
loss, and/or isolation, you must return the duplexer for repair.
6871022P86-A - November 2012
5-23
Содержание GTR 8000
Страница 2: ......
Страница 4: ......
Страница 6: ......
Страница 14: ......
Страница 18: ......
Страница 22: ......
Страница 26: ......
Страница 60: ......
Страница 80: ...GTR 8000 Base Radio Figure 2 22 Base Radio Backplane Mounting Location 2 20 6871022P86 A November 2012 ...
Страница 177: ...5 8 1 3 VHF Tuning Procedure Figure 5 1 Preselector Tuning VHF 6871022P86 A November 2012 5 7 ...
Страница 181: ...5 8 2 3 UHF Tuning Procedure Figure 5 2 Preselect Tuning UHF 6871022P86 A November 2012 5 11 ...
Страница 230: ......
Страница 234: ......
Страница 244: ......
Страница 286: ......
Страница 300: ......
Страница 338: ......