ORIGINAL MESSAGE: (may be snipped)
n 1/18/2014 9:52 AM, Jim Garland wrote:
I agree that one shouldn't leave the unused segments of of a tank coil
completely floating, and I don't do that. As you suggest, I connect the
wiper on the bandswitch to the cold (antenna) end of the inductor so that
the switch shorts the unused segments. For esample, if operating 10m, the
15m tap is shorted by the wiper to the 160m tap at the far end of the
coil.
REPLY:
This method works and is commonly used, but there is another way, which I
think has some advantages.
I have separate coils for each band. They are NOT magnetically coupled to
each other even though they are in series. Each coil is oriented 90
degrees to it's neighbor and they alternate vertical and horizontal with
each band so the coils do not "see" their neighbor.
The tradeoff is this requires larger coils, since even though they are in
series, they have almost no magnetic coupling between them. The advantage
is that none of the coils need to be shorted out by the bandswitch and
therefore no current flows through the "short". I know this approach will
not appeal everybody but it works for me.
73, Bill W6WRT
Brute force survivability, whatever floats your boat is fine by me.
There are many ways to design and build an amp, from neolithic to elegant; I
fall somewhere between those extremes as do the majority of ham and
commercial amps.
Carl
KM1H
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