> Some tuners won't tune a 1/2 wave wire, since the
impedance is
> 800 to 3000 ohms. There is an easy fix for this; put a
doorknob
> capacitor of 50 to 200 pF from antenna to counterpoise.
Now
> your tuner will probably be happy, because the impedance
is
> now in the 100's of ohms.
Why?
The impedance would increase with the capacitor, not
decrease. The antenna is resonant Rick.
> You can even put the capacitor right at the end of the
wire
> and drop the counterpoise from that point (all outside).
> Then connect the tuner to the door knob with coax.
He needs a counterpoise as Jim suggested. No way around
that.
I'd use the room radiators, the rain gutter, metal window
frames, any metal railings, and maybe even aluminum foil
under the carpet as part of a counterpoise. The more
electrical mass the better. The more spread out and massive
the counterpoise, the less the counterpoise will radiate and
pick up noise. The more massive the counterpoise, the less
RF in the building.
Tie anything large and metallic into the counterpoise and
ground it to the tuner. If you still have problems, then you
might consider a choke balun between the tuner and the rig,
and keeping the tuner need the window.
73 Tom
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