Terry, post this for me

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

Original poster: "Patrick Leonard by way of Terry Fritz <twftesla-at-qwest-dot-net>" <transactoid-at-rogers-dot-com>

Okay, here is my post for probably the billionth time. I don't know if you
did post it the first time, but here it is again:

Patrick is not able to post to the list (Chip working on it) so I'll post
for him - Terry

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After all the troubles I had...breaking the wire while winding, my mangled
primary, and the discovery that my primary won't give enough inductance, I
fired my large coil (in comparision to my small coils, that is :) up.

Anyway, I wasn't exactly shocked (pun intended) by its performance. I'm
using a 12/30 NST (tho will be using a 15/30 later, and have plenty of NSTs
to add). I can draw about 7" - 9" sparks, and I get no breakout from my
toroid which is 4" x 22". I SHOULD be able to get at least 36" out of this,
right?

The secondary is 28" of 28-guage wire wound on 4" pvc. I realize this is
considerably over the optimal ratio; could this alone be the reason? I read
about someone's bipolar coil that was using 48" of 4" PVC pipe wound with
#28 guage, so that is almost twice as big as mine, and he was getting
something like 40" discharges.

My primary is about 16 turns of 1/4" copper pipe spaced 1/4" apart.
According QuickTC, My tap point won't be until around turn 20 or so. This is
what I'm thinking is probably the key reason for my small discharges.

My capacitors are 8 SW caps....I realize MMCs would be better, but as an
unemployed student, I can't really afford that right now.

So, what can I do to get nice BIG sparks? First of all, I'm going to add
another 4 SW caps. I tried winding 15 turns of coax to make a "tuning coil"
and that improved spark lenght a bit (just random guess on the 15 turns). I
also tried using this coil as a cylindrical primary coil, and I got racing
sparks so it's very much overcoupled.....perhaps if I decreased the number
of turns I could just use a cylindrical primary instead?? Someone on this
list suggested I cut my secondary in half, to fit it within in the standard
ratios. I really don't want to do this. After all the time I put into it
just to cut it in half? I'd rather make everything else work with my
secondary.  BUT If cutting it in half will _guarantee_ me considerably
better results, I'll look into doing that. Also, it's just grounded to mains
ground. I'm sure this impacts performance, but I'm also sure this alone
isn't the reason for my minimal sparks (I can't work outside right now, so I
have no other choice).

After all the work, I was quite diappointed.  My small coil wound on a paper
towel roll makes sparks almost this big, and I whipped that one together in
about 30 minutes!

Thanks,
Patrick.
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BTW, if you can provide any suggestions for the above problem, I'd
appreciate it :)