RAT5 Manual version 1.2.0
RAT5 Information Manual version 1.2.0 © GW4GTE 2010
Page 17 of 29
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With an input signal present, If a signal cannot be heard in the loudspeaker,
double-check the LO frequency. Rotate the tuning control and also try
increasing the signal level applied to the antenna input.
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Assuming an RF signal is being received, check the S-meter reading (multi-
meter). Keep the voltage in the centre portion of the range as you proceed
i.e. about 1V to 2V. Adjust the RF input level as required.
Tune L2 by rotating the ferrite core from its preset position, tuning for a
maximum S-meter reading. The tuning will be quite broad, but it should be
possible to establish a centre position for the core. It’s a good idea to monitor
the LO at the same time, making sure the test carrier is tuned correctly so as
to place the IF signal in the centre of the filter.
4.4.2 RF Alignment.
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Check the S-meter reading (multi-meter). Keep the voltage in the one volt
area of the range for best sensitivity. Adjust the RF input level as required.
Tune the ferrite cores of T1 then T2 for a maximum S-meter reading. Repeat
the procedure until no further improvement can be made. The input signal
level may need to be reduced as the filter is adjusted.
RAT5 alignment is now complete
