"Uncle Peter" ) writes:

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.

I always thought the concept of an "active antenna" was that you had a
short whip and barely loaded it down. The whip itself is connected
to a very high impedance point, and then the active components are
there to transform that into a lower impedance for the receiver.

You basically see the idea in old car radios, where the whip was
connected across the tuned circuit at the input. If you didn't use
the right cable to connect it to the antenna, and if you didn't use
the trimmer to adjust things to compensate for that cable, you'd
lose a lot of signal.

Then solid state devices came along, and that made it much easier
to do the transformation, since they took up less space and didn't
need filament voltage.

A preamp or even preselector is not the same thing as an "active
antenna".

Michael VE2BVW