Re: coupling

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

Original poster: "Barton B. Anderson by way of Terry Fritz <twftesla-at-qwest-dot-net>" <tesla123-at-pacbell-dot-net>

Hi Ry,

Tesla list wrote:

> Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<rblaisdell-at-juno-dot-com>
>
> I think I have poor coupling.
>
> I have 1/4 inch copper tubing primary.  3/4" inside to inside spacing so
> 1" center to center.
> and 2" between innermost turn and primary.
> What do some of yall run?

3/4" spacing between turns is large, but it's not a real problem unless you
can't move
your secondary up or down. I run 0.375 inch primary spacing with the same wire
diameter. On coils ~8" and below, I'll keep the sec to pri spacing around 1
inch, but
ultimately determined by the ballpark cap voltage. You need to either be
able to move
the primary or secondary vertically to adjust coupling. Lowering the
secondary will
increase coupling. Because of this, the primary really doesn't need to be
modified.
Yes, reducing the proximity by changing the primary will increase coupling,
but it
shouldn't be necessary.

Take care,
Bart