Great stuff...thanks Richard!

Ive got a homemade tuner going at present that is doing a good job of
taming all the signals that my 70ft. wire is getting....so things are
really getting fun! (even the hour putting up the wire early Sun day
morning, about -35 degrees.. ;-)

Thanks again

Mike



Richard Harrison wrote:
Mike wrote:
"I was mainly concerned with signal loss due to load mismatch if I use
coax to get the signal into the basement for the wire."

A versatile tuner allows a match between antenna and radio under most
conditions. It does not prevent an unshielded and imbalanced line from
picking up noise on the path to the radio. Coax may avoid noise pickup.

Autotransformers at each end of the coax can give high-impedance match
at the antenna and at the radio. Such transformers are used to match
Beverage Antennas to coax.. See the "ARRL Antenna Book" or ON4UN`s
"Low-Band DXing" for ferrite-winding details.

An air-core transformer at each end of the coax can step up / down the
impedance too. Suppose you want to match 450 ohms to 50 ohms. The
impedance ratio is 9 to 1. The turns ratio is 3 to 1.

The reactance of the primary may ne chosen as about 10 times the 450
ohms or 550 ohms of the antenna. About 500 microhenries (0.5 mhy) would
work. My ARRL L/C/F Calculator shows the number of turns per inch, wire
size, coil diameter, and coil length needed to make the coil.. There`s
nothing critical about it. Its inductance was an arbitrary choice.

The coils are tapped up about 1/3 of the turns from the cold (grounded)
end of the coil, for the coax connection. The full coil is used across
the antenna and across the receiver input.

If you have no noise, a single wire connecting your receiver to the
antenna will likely grab more signal and lose less of it on its way to
the receiver.

I`ve used the transformers on each end of the low-impedance line
(twisted pair)) to the receiver. This system was part of a 1938 GE
"V-Doublet" antenna kit. It was a quiet all-band signal grabber.

Best regards, Richarrd Harrison, KB5WZI