This is measured from the lowest point on the toroid's minor dia (bottom of
the ball) in a vertical line (note --- not direct line) to the last winding
on the sec coil.
No pancake on the sec. coil.
Example to clarify: If you have a 30 x 6" toroid, then 1.2 x 6" (minor dia)
= 7.2" elevation above last turn of sec coil.
1,2 x minor dia. elevation balances electrostatic protection of sec and
reduces the "shorted turn effect" of the toroid itself, which tends to
reduce output slightly.
There is a rather scientific method you can use (which I used to distill my
equation):
Set up a camera digital or preferably an old film camera with 400 ASA black
and white film (best).
Shoot various 5 sec timed exposure in complete darkness while elevating your
toroid to different levels, ie, 1.2, 1.3, 1.4, 1.5 .... up to 2.5 x minor
dia.
Carefully record the film frame number and also the elevation to match each
frame.
You will see some corona emerging at 45 degrees from the last turn on the
sec. When the elevation is correct this corona is supressed such that a
small amount issues at an angle of nearly 0 degrees (even horizontal level)
or slightly above horizontal. When this angle is at 0 degrees this is
optimum supression and proper balancing of these two effects.
If the angle is below the horizontal plane of the last sec turn, then you
are beginning to enter the zone of shorted turn effect of the toroid itself,
which is undesireable.
A perfect balance can be achieved in all coil setups using the procedure I
have outlined above. If you don't have an old film type camera, digitals
can be
used but it may be somewhat dangerous to your camera to get it close enough
to work properly. I prefer an old film camera for this experiment.
Time permitting, I usually do this on most new coil designs I build.
I've charted my data from many coils and the equation is usually within 5%
by using 1.2 x toroid minor dia for proper elevation.
Dr. Resonance
On Sun, Jan 4, 2009 at 8:59 AM, Karl Thorkildsen <
karl.thorkildsen@xxxxxxxxxxxxx> wrote:
> When you say "base of the toroid" do you mean the lowest point or do you
> mean the pancake?
>
> Yes I understand you can aim the breakout point upward.
>
> If I understand coupling correctly I believe I am at about .125. That is 8
> halfwaves to ring down? Here's my scope reading:
> http://www.thorbass.com/images/Tesla/secondcoil/tuning2.jpg
> - Karl
>