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Re. Great sparks! Then....
>Original Poster: Travis Tabbal <bigboss-at-xmission-dot-com>
>
><snip>
>
>One question, durring my higher powered runs I noticed something I had not
>seen before. I kept getting a small arc from my secondary ground wire to
>the inner turn of the primary. This happened at the higher power levels. I
>tried putting some poly in the way, but that didn't help.
>
>Do I need a larger inner turn on the primary? Or am I missing something
>here? I'm a few turns in from the outside on the tap, so I could loose a
>turn or two from the center and retune still. It's a 6" secondary with a
>flat spiral primary, inner diamater on the primary is 8".
>
>Travis
Do you have air core chokes?
I once had a problem were any part of my tank circuit wanted to arc to
ground. The problem was my use of large air-core chokes (~8mH, 2"Dx7"L)
in a classic LCR low-pass filter NST protection circuit, between the main
gap and the NST terminals. Despite my using 3K ohm de-Qing resistors,
the chokes insisted upon ringing, elevating my entire tank circuit to
some incredible potential above ground. Changing to heavily insulated
ferrite-core chokes eliminated the problem, though I now believe that
chokes do more harm than good.
Regards, Gary Lau
Waltham, MA USA