20. Final adjusting the Rx-part of the filter.
20.1 Connect a 50 ohms terminator to the "Tx"-port.
20.2 Connect a powermeter and dummyload directly to the "Ant"-port. The dummyload must handle full power. (4W for a 10W transmitter).
20.3 Connect a VSWR meter DIRECTLY to the RX-port.
The VSWR-meter must be designed for measuring low powerlevels (max 10W).
20.3.1 Connect a transmitter to the VSWR-meter. The transmitter should be best of the synthesizer-type, have tuningsteps of 2.5 kHz and an output power of several watts, and must be able to withstand bad VSWR. A more powerfull transmitter can be connected via an attennuator. Connec the attennuator via a 1/2 wave cable to the VVSWR meter.
20.4 Adjust the transmitter exactly to the uplink-frequency (Rx-frequency of the repeater).
20.5 Tune the "Rx"-finetune-bolts at first for about maximum output, at the same time observing the VSWR. Begin at the "Ant"-side and work backwards to the "Rx"-side of the filter.
20.6 Then finish and finetune for minimum VSWR, at the same time observing the output.
Begin at the "Rx"-side, working towards the "Ant"-side of the filter.
20.7 Repeat the finetuning to minimum total VSRW.
20.8 VSWR should be lower then 1:1.5 (1:1.2), and insertion loss should be abt. 4 dB.