Re: Primary Resonant Frequency question . . .

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "S & J Young by way of Terry Fritz <twftesla-at-qwest-dot-net>" <youngs-at-konnections-dot-net>

Possibly a better way than a roller inductor would be to use two off-axis
inductors and vary the spacing between them.  E.g. two flat spirals parallel
to each other in series.  This avoids moving contacts with huge peak current
through them, and you can do real-time tuning easily.
--Steve
----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Sunday, August 18, 2002 12:47 PM
Subject: Re: Primary Resonant Frequency question . . .


> Original poster: "Andy Cobaugh by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<kb3ewy-at-rcn-dot-com>
>
> Dan,
>
>     I would agree with John here and go ahead and buy/make some sort of
> variable inductor.  The one that I have always used since I started this
hobby
> can be seen here:
>
<http://users.rcn-dot-com/tcobaugh/files/hv/rollerinductor.jpg>http://users.rcn.
> com/tcobaugh/files/hv/rollerinductor.jpg  When I use this with my big
coil, I
> had to modify it slightly, and I use a long piece of 3/4 PVC pipe to turn
it.
> It makes tuning a cinch, you can see if you need more or less inductance
by
> simply tuning it, and it makes it really easy to tune off frequency to
> compensate for streamer loading.  The inductor was bought by my dad when
he
> first got his ham license to be used in an antenna matching device.  TTYL
>
> Cheers,
>
> Andy C.