Sailor RE2100, Technical Manual

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3 SERVICE RE2100
3.6.2.2 CHECK OF FRONT END GAIN
In this test the available power gain of the Front End Unit is controlled. The gain is determined by an
indirect measurement and it is therefore necessary to correct the measured data afterwards.
In the test procedure given below, the input and output levels of the Front End Unit are measured by
means of the diode probe. To avoid mistuning of the 70 MHz output filter, because of the capacitive
loading introduced by the diode probe, it is necessary to measure the output level through a voltage
divider. The Front End Unit must then be terminated as shown in the figures below, where the wanted
loading impedance of 800 ohm is realized with a voltage divider consisting of a resistor of 750 ohm in
series connection with a resistor of 50 ohm.
Termination of the Front End Unit for measurement of the available power gain. The termination is
realized at the Receiver Unit (module 1).
The resistor R185-1 must be disconnected as shown above, before the termination of the Front End Unit
can be implemented.
1. Terminate the Front End Unit as shown in the figures above.
2. Turn the RE2100 on.
3. Choose generator frequency f
G
, generator output level V
G
, and receiver frequency f
RX
as specified
in point 10.
4. Connect the diode probe across the 50 ohm resistor in the Front End terminating network (see
figure above).
5. Notice the diode probe voltage.
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