Re: anyone? shortform and inner primary?

Tesla List wrote:

> Original Poster: arrie <solva-at-xs4all.nl>
> Want to build my primary inside the secondary. Believe that with a tight
> coupling much less input power is needed and a much higher q is achieved!
> Tuning the primary will be more hassle but lifting will be easier on the
> other hand.
> and: who has experience with very large diameter and short forms?
> who?

    Arwin, the inductance of a coil depends on diameter. Wide secondary coil
would mean greater inductance, lower frequency of oscillation. And narrow
primary coil would mean lessened inductance, higher frequency of
oscillation. So to tune such a Tesla coil you'd have to tap the primary at a
much higher number of turns, resulting in less voltage gain per turn of
secondary coil.
    Then there's the internal arcing problem. And the waste of your
painstaking work and half-a-mile of wire on a huge secondary coil-- unless
the short form you're talking about is really short, in which case there's
not much voltage gain going on.
    These are some of the reasons nobody does this. Cool image, though-- a
self-contained Tesla coil: just a squat black cylinder --like a lady's
hatbox-- with a cord coming out the bottom.
    Or a whoopee cushion!