Question for the group...
"Dave" wrote in message
...
I am doing this inside of the active antenna case, using the coils used
for tuning the tank circuit. It's really kind of an unusual setup, I
gather. I am trying to use the resonance of the coil, which is in
parrallel with my tuning capacitor, to set up a sympathetic signal in the
second layer on that same coil, and feed this sympathetic signal to my
first stage of amplification. That's the step-up transformer part. The
whole thing just resonates at a higher frequency than I anticipated. Thus
my original question: has anyone heard of this before, and what is it
called/where can I find more info on the subject. Fortunately it still
allows me to pull in my target shortwave station, but it's at the bottom
of the tuning range rather than the top.
Thanks for your help,
Dave
Hi Dave
Then in effect, you are trying to match a lower impedance to a higher one
since you are trying to increase the voltage gain.
Without knowing the active antenna you're attempting to use, it is kind
of hard to determine what advice to offer. I think you mentioned a 100 foot
long wire... That would have a much lower impedance over the HF range
than a 3 foot whip. If you just want voltage gain, use several turns on
the bottom of the coil for coupling the antenna to the tuned circuit.
The tuned circuit will provide the voltage gain. You will reach a point
where the active antenna will be prone to overload, even with the tuned
preselector input.
Pete
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