My second coil attempt, advice?

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Scott Bogard" <teslas-intern@xxxxxxxxxxx>

Hello all,
    I am a relative newbie to the list, and I have recently finished 
my second Tesla coil (60Hz AC system), and the output is Ok (strikes 
38 in, and streamers about 5 ft tops) but I have seen very similar 
coils put out as much as 8 ft or more.
    Here are the specs,
    Power supply:  6 MOT stack, center tapped ground (~12kV out 120V 
in ?? amps, I don't have the tools to actually measure this) no 
variac, full power or nothing.

    Ballast: 1 MOT (shorted of course).

    Tank capacitor:  75nf Maxwell, tested at 81nf (so the label says anyway).

    RF filter:  ohmite resister 50 ohm "chokes" filled with 4 
welding rods for "inductance" and some ceramic capacitors about 600pf 
(I don't know if it works or not, but there isn't much interferance 
on our TV unlike my old (smaller) coil) and safty gaps to ground (I 
don't use a mains ground at all, I use a seperate peg in the ground 
from the RF ground for the MOTs and safety gaps).

    Secondary: 6in PVC 22AWG wound 31 in (+-1160 turns) three super 
thick (uneven) coats of polyurethane.

    RF ground: copper pipe pounded in about 1.5 ft (the ground may 
still be frozen down there).

    Top load:  2 aluminum flex duct toroids covered in foil tape, 
3in*15 and 7in*21 (I tried a large 11.75*42, but got no streamers 
breakout with it connected).

    Primary:  1/4in copper (refridgerator) tubing, spaced .75in 
apart with an 8in hole in the middle for the secondary.  Tapped 
between turns 7 and 8, and sits just a hair below the first secondary 
winding (no racing arcs yet, moving it downward  lowers the 
performance, moving it up changes nothing).

    Wiring: tank circuit-14AWG rated at 15kV, other wire-whatever I 
had lying around (18AWG 20kV, some house wire, and some 22AWG magnet 
wire, run through polyethylene tubing for insulation).

    Spark gap: (probably my performance killer) single blower static 
gap, two brass bolts filed roughly to points (I use pointed contacts, 
because smooth rounded contacts on my first smaler coil, instantly 
gave me terrible (really really bad) racing sparks, and the pointed 
ones gave fairly smooth nice operation,) currantly .75cm or just 
between 1/4 and 1/2 in. seems to give best results.  My saftey gaps 
are set much narrower than this, but they have rounded contacts and never fire.

    I am building a synch rotary, but it will be some time until it 
is ready, I do however have a much stronger blower on the way (the 
currant one is lousey compared to the one that is coming).  The 
output is Ok but somwhat inconsistant (I am running it outside, and 
it is very moist here right now with snow melt and rain) sometimes it 
will strike the strike rail 38in away while two additional long 
streamers fly out in the air, and then a second later all you will 
see is one tiny streamer 2.5 feet long or so, and it does everything 
in between totally randomly.  Aside from building my rotary gap, is 
there anything I can do to tweak just a little more output out of the 
thing (a breakout point reduces the output, but makes it easier to 
see as it doesn't move around the toroids).  Thank you much
Scott Bogard.

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