Re: Off-axis primary tuning

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

Original poster: "J. B. Weazle McCreath by way of Terry Fritz <twftesla-at-qwest-dot-net>" <weazle-at-hurontel.on.ca>


At 10:46 AM 27/11/02 -0700, you wrote:
 >
 >Original poster: "S & J Young by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<youngs-at-konnections-dot-net>
 >
 >
 >Has anyone experimented with an off-axis variable inductor to fine tune the
 >primary while the TC is operating at full power?  If so, please share your
 >design and results.
 >
 >I am especially interested in a design with no moving contacts, such as a
 >pair of spiral coils with remotely controlled variable spacing to change
 >the mutual inductance.
 >
 >Thanks,
 >--Steve Young
 >

Hello Steve, Coilers,

You might try a variometer arrangement where one coil is placed inside of
another, connected in series, and with an arrangement for rotating the
inside coil.  In one position their inductances add, and then with a 180
degree rotation of the inner coil, their inductances cancel.  The "Old
Timers" will remember this as a common means of tuning used in the early
days of "Wireless".  For TC application, you would connect it into the
primary circuit, tapping in slightly from your normal tap position to
compensate for the added inductance.

73, Weazle, VE3EAR/VE3WZL
G-1#1214

Listening: 147.030+ and 442.075+
E-mail:    weazle-at-hurontel.on.ca
            or ve3ear-at-rac.ca
Web site:  http://www.hurontel.on.ca/~weazle