24. Measuring the receiver-notch in the downlink-part of the filter.

24.1 Connect the signal generator directly to "Ant", or via 50 ohms cable, a 1/2 wave long (68 cm), or 1/1 wave wave long (136 cm).

24.2 Connect a 50 ohms terminator to "Rx".

24.3 Connect the signal detector to "Tx", via a 50 ohms cable, 1/2 wave long (68 cm), or 1/1 wave wave long (136 cm).

24.4 Tune the generator and the detector to the exact uplink- (repeater-receiver-) frequency.

24.5 Turn up generator-output until a good readable value is indicated at the detector.

24.6 NOTICE the signal-level at the detector, and the amount of attennuation at the generator. Do not change the output of the generator at this moment.

24.7 Check that the signal you see is the signal coming from the filter.

24.8 If OK, reduce the signal of the generator fully and connnect the generator-cable directly to the detector-cable.

24.9 Turn up the signal until the same signal level at the detector is obtained then before, when measuring trough the filter.

24.10 NOTICE the amount of attennuation on the generator.

24.11 The difference in attennuation with/without the filter is equal to the notchdeepness in the "Tx"-part of the filter. It must be 90 dB or more.


<< VV