Re: Redesigning/tuning a coil

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

Original poster: pepperman-at-SoftHome-dot-net 

Thanks to everyone who explained the tuning with scrap wire--it
makes a lot more sense now.  Quick confirmation--you guys were
suggesting tuning by watching the spark distance at 30% power,
rather than using a signal generator and an oscilloscope?  Which
do you think would be easier/faster?

I also think I'll just go with the existing toroid for now (thanks for the
advice on this too)--it'll be cheaper than buying new ducting, and
sounds like it should work.  If it doesn't work after all, I might try a
new toroid.

About the primary--the most 1/4" copper tubing we were able to get
on short notice was 42', which works out to about 8.5-9 turns on the
primary (ID of 12", 1/4" between turns, ~20" OD [I think]).  Should I
just use the scrap wire, find the tuning point, and then add
capacitance until it brings the tuning within the 8.5 or so turns on
the primary?  I'd like a primary with more turns, but right now it
looks like I'll probably just have to work with the length I have.  I
don't want to push it too close to the outside of the 8.5-ish turns,
though, since it will only be an approximate measurement; maybe
instead I'll put it somewhere in the 7ish range (on the scrap
primary) to avoid going over the 8.5 or so that I have.  Sound like a
good idea?

Michael Johnson