Re: Still mystified by odd TC behavior, what gives?

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

Original poster: "Malcolm Watts by way of Terry Fritz <twftesla-at-qwest-dot-net>" <m.j.watts-at-massey.ac.nz>

Hi Jonathon,

On 19 May 01, at 10:26, Tesla list wrote:

> 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.

What kind of earthing arrangements do you have for the secondary?

Malcolm