User's Manual

Used gain
Actual momentary gain for the uplink and downlink transmission.
The gain may differ from the setpoint value due to poor antenna isolation.
An antenna isolation test feature regulates the gain as follows:
- After powering up, resetting or updating, the gain is increased to
13dB above the Control to level (see Figure 10-8).
The purpose of this 13dB ’over-gain’ is to test if there is a 13dB
antenna isolation margin. The gain increase can be seen in the
Control to and Used gain fields.
- If no instability due to poor antenna isolation is detected during the
antenna isolation test, the gain is decreased to the Control to level
after 30 sec.
- If instability due to poor antenna isolation is detected during the
antenna isolation test, the gain is decreased to a level 13dB below the
lowest detected poor antenna isolation level (see Figure 10-9).
Warning alarm is activated when instability is detected and Ceasing
when the instability has ceased.
- The decreased gain level is kept for the next 60 minutes. Then, a
new antenna isolation margin test is performed.
93dB
Control to 80dB
Figure 10-8. Antenna isolation margin test
Instability 85dB
Control to 80dB
72dB
60 min.
Figure 10-9. Gain regulation at poor antenna isolation
ALLGON System AB AR Repeaters & OMT32 Software – Repeater Operations
User’s Manual VD202 90/EN Rev. 1A 1999-07 10 - 16