Still mystified by odd TC behavior, what gives?

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

Original poster: "Jonathan Peakall by way of Terry Fritz <twftesla-at-qwest-dot-net>" <jpeakall-at-mcn-dot-org>

Howdy All,

I have been struggling for over a week to figure out what the heck is
going on here. If anyone can help me, I'd be soooo happy. Here is the
situation:

Basic coil specs:

Small secondary, 450 wraps of 22 AWG on a 3.5" form.
Primary: Either a 12 turns 12 AWG auto wire on a 6.5" form, or 15 wraps
10 AWG auto wire on a 8" form.
PSU: Either a 12kv/120ma or 15kv/60ma.
Vacuum single gap
RF filter ALA Terry

I recently got a Resonant Research Inc. .025 (actually tests to .023)
tank cap. When I try to use it, with either transformer or even with
both ganged up in parallel, I get no output from the secondary,
regardless of how I tune the primary or set the SG. I can draw a wimpy
spark to a ground rod, but that's it. The gap fires fine over a range of
settings. As soon as I add another cap in series to the .023 and lower
the capacitance, it fires up. Yet the gap isn't acting as I have seen in
the past with too large a tank cap, which has always resulted in erratic
SG performance.

The only thing I can think of is that the "sweet spot" is really small,
and as I only have taps on each turn on the large primary I haven't hit
it right. Is it possible for the tuning to be so sensitive that one gets
no output unless really close? The gap sounds mean and hot, but is it
possible that the .025 cap is damaged? It seems unlikely considering the
fury of the gap.

If you can help, you're my Hero!

TIA,

Jonathan Peakall (The other OTHER Jonathan)