Re: Terry's remote tuning idea
Terry Fritz wrote:
One of my new projects (one of a zillion I have planned for the cold
months ;-)) is to make a remote primary tuning device.
I will have an "extra" MMC with four stings. They will have a
value of 0.5, 1.0, 2.0, and 4.0nF (could be other values too). This
will be parallel with the regular primary cap. By selecting the strings
a binary fashion, I can select from 0nF to 7.5nF of additional
in 0.5nF steps.
Any help, ideas, etc. are welcome. It would really be cool to adjust
gap and primary tuning remotely from simple switches.
I used a 'Litz Wire' primary tuner on my 30kVA coil,
which works quite well. It does not require sliding
or moving electrical contacts. The final half-turn
of the primary winding consists of a link of heavy
Litz cable, made up by weaving eighteen #8AWG wires
connected in parallel. This cable is slung directly
under the primary coilform, and effectively adds or
subtracts up to one-half of a turn, depending how it
is positioned. A motorized linear screw travel allows
the Litz cable to be adjusted remotely.
I did a writeup on it in TCBA Vol 10 #2, if you have
a copy of that one.