Re: Tesla Software

> "I was planning to use the Medhurst and Wheeler's formulae as most seem to
> agree they are accurate enough. I will include a list of all formulae used
> so that people don't think the results are derived from sucking on my
> pencil. Do you think more accurate inductance formulae are necessary and if
> so which would be best to use."
	The answer is that M & W are plenty good enough, in my
opinion.  They get you in the ball park and you have to do your
final tuning anyway.  The problem comes when trying to estimate
the added effective capacitance when you put a terminal on top of
your coil.  There are no simple formulae to estimate that, and
it's sort of "guess and by gosh".
	By the way, right now I have a small 3" coil running with
a roller coil in the primary to permit continuous tuning.  When
excited by about 600 watts and running 24" streamers a change in
primary inductance of 10% (resonant frequency change of 5%) is
noticeable but not dramatic.  This is with a 14" by 3" toroid
terminal on top.  I am sure that "single shot" measurements, with
the power input adjusted to just cause breakdown, would show a much
sharper resonance, as the measured secondary Q of this thing is
around 300 at its resonant frequency of about 280 kHz.  However,
once the discharge starts and the ionized air cloud develops the
shunt resistance due to the discharge is low enough to drop the
apparent Q way down, and there are detuning effects due both to
the ion cloud and the lowered shunt resistance.  For a double-tuned
circuit like this both require you to increase the primary inductance
or capacitance (lower the resonant frequency) to effect maximum
power transfer.