tweaking

["Richard Barton" <richardbarton-at-caving5.freeserve.co.uk> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

Hi all
	I'm at present perfecting my smallish coil to achieve its best
performance. It's powered by 12/90 NST (3 in parallel), running into
a 6.5 turn copper 1/4" pipe primary, through a 8.5nF beer bottle cap,
with a 5 stage stationary spark gap. One of the gaps can be adjusted
whilst running, through a worm-screw and insulated rod. The Secondary
is around 650 turns of 28 SWG and is about 10.5 inches long. The
Secondary form is white ABS, 4 inches diameter.
The primary is a cylindrical shape, supported on 6 insulated struts.
I'm getting just on 10" of noisy white arc to a grounded ball. The topload
on the coil is a 2" polished steel ball (chromium plated). I've tried bigger
toploads but the power seems to diminish.
The primary and secondary are pretty closely coupled, with the occasional
arc across. (I have safety gaps). I get a fair bit of brush discharge from
the
top few windings of the secondary. (White, with a bluish tinge).
In order to improve the output, should I remove a few windings from the
top of the secondary ? Will this stop the wasted leakage from coming from
top windings and get all the power into the topload ?
If I adjust the tapping from the primary coil, it doesn't seem change the
output,
even with half-a-turn of adjusting ! My RF ground is a 5 ft steel rod
hammered
down to almost ground level in sandy soil, watered with a hosepipe,
connected
to the system with car jumper cable, and clips.
Any ideas for getting that bit more power ?
						Richard Barton.