Re: what's wrong with my coil?

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

Original poster: "Jason by way of Terry Fritz <twftesla-at-qwest-dot-net>" <jasonp-at-btinternet-dot-com>

Robert,

That's a tricky one... comments below

> Primary - flat spiral with x number of turns where x depends on what
> topload i'm using, 8.5" ID, quarter inch copper tubing spaced a quarter
> inch between turns.
Maybe more spacing would help stop arcing but I cant see why it would
decrease output, assuming its not arcing at all.

> secondary - 4.5" diameter, 23 inches high, 22 gauge wire on a pvc form
> sealed with polyurethane (smooth as glass)
What I use :) Lovely. Got any pics you could send me???

> spark gap. RQ/TCBOR gap hooked up to my shop vac.
> capacitor - LTR geek mmc bank.
That should be fine.... LTR??/ What value is this???

> topload - 4" dryer ducting bent around 2-10" pie pans and covered in
> aluminum tape.
Also what I use

> secondary is grounded in my garage to a large array of aluminum foil
> sheets.
possibly bad - I would switch to a copper rod driven into the ground.

> coupling is pretty good, since the base of the secondary is about 2
> inches underneath the primary with no racing sparks, any farther under
> and i get racing sparks, so it's just about as coupled as it can get.
> input power is 1.35kva (9/150) and the spark length is only about 2.5 to
> 3 feet at most. the arcs aren't even that hot either. i've seen coils
> that get 4 foot arcs using just a 12/60. is there anything i can do to
> improve spark length (besides upgrading to Marc's trigger gap, which I
> am currently working on). thanks a lot,
> Robert

The only thing that I can think of is the tuning. Try changing the tap
point - that may be the problem. The other problem could be your gap firing
erratically - try it with and without the shop vac - it may work better if
not quenched so much.

Good luck,
Jason