Dear Mal, LF Group,
At 19:59 10/06/2002 +0100, you wrote:
. Two taps on the coil permits freq adjustment from 135.7 - 137.8 khz...
Something is wrong if you need to adjust the tuning within this range - the
output should be flat within a fraction of a dB over the whole band
without re-tuning.
Incidentally, an inductor that works OK for a low pass filter won't
necessarily be suitable in this type of tank circuit - in the low pass, the
loaded Q of the circuit is usually 1 or less, depending on design, while in
the tank circuit it is about 6. This means the tank circuit inductor has
to cope with reactive power several times greater than the low-pass
inductor for the same power throughput - so beware!
Cheers, Jim Moritz
73 de M0BMU
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