I completed my first coil this last weekend and did a
few unusual things in the construction. The helical
primary is much larger diameter than required for such
a small primary. I used a secondary coil that I wound
in High School 25+ years ago, and intend to replace it
later with a large coil. To help comphensate for the
loose coupling I moved the primary up a couple of
inches. As I understand it, the maximum coupling
would be with the primary centered half way up the
seconday, but this location would result in
overcoupling the coil. I chose a height that I
beleive was a good compromise.
A friend with a lot of tesla experience what I had
done and objected. He insisted that I needed to "drive
the coil from the bottom". While tuning the coil we
ended up removing several inches of turns from the
bottom of the secondary coil due to his insistence.
Now that the coil is working, I'm considering moving
the secondary down to it's original elevation. Who is
right here? Is there a reason (other than over
coupling and increased possibility of arc over) that
this should not be done?
Thanks,
Curt.