RE: Redesigning/tuning a coil

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

Original poster: "Lau, Gary" <gary.lau-at-hp-dot-com> 

Off-axis coils are occasionally used in series with the main primary,
mostly for fine-tuning.  The thing to remember is that the overall
pri-sec coupling will be reduced when using an off-axis coil.  If the
inductance of the off-axis coil is small compared with the main primary,
the reduction in coupling will also be small.  But is much of your
inductance is in the off-axis coil, your coupling may be too small.

If you can't get enough tubing right away, just use #14 or #12 solid
copper wire until you can get more tubing?

Regards, Gary Lau
MA, USA

Original poster: pepperman-at-SoftHome-dot-net

Just another thought about my limited primary--if having a high
enough primary inductance is the reason for wanting the coil to
tune at 10-15 turns, what about just adding an off-axis inductor?
Would this do the same thing?  If I did it, what would be the
minimum acceptable wire/tubing diameter?  Since I very well may
not be able to get more of the 1/4" copper fast enough, I'll probably
need to try something else.

Michael Johnson