--- In softrock40@..., KD5NWA <KD5NWA@c...> wrote:
If you are going to put a pre-amplifier in front of the QSD that I
would suggest a better pre-amplifier than a MMic chip. > >
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I would 'not' use a pre-amplifier stage.
In the QEX article a gain of 6 was obtain from the input transformer
which should be enough to overcome the losses in the BPF. Need to run
the AADE program to verify.
The rule of thumb for the design of an RF stage is give it just enough
gain to overcome the tuned circuit losses. T1-4 does this plus
provides a degree of isolation.
I would use high Q inductors (not the store purchased ones) and high
quality RF capactors in the BPF.
Sometimes less is better. At least in this case this appears to be
true.
Stan AK0B
