secondary/primary distance

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

Original poster: "Matt Skidmore by way of Terry Fritz <twftesla-at-qwest-dot-net>" <fox-at-woozle-dot-org>

im in the process of creating a new coil with a secondary with a diameter
of 8.5 inches. what is a good diameter for the first turn of the primary?
10, 12 inches? what effect will this have on the coil?

ive also been wondering about using 1/4 copper tubing vs 3/8 and then the
spacing between turns.

ive been playing with the java TC designer, and the TCcad program (all
which are simply wonderful help). thr TCcad program doesnt like
calculating for more then 15 turns. starts to calculate for me when i give
it a primary diameter of about 24 inches (7.7 spacing between secondary
and primary). any help on this would be greatly appreciated. thanks

-matt