Re: Help with calculating secondary self resonant freq?

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

Original poster: "Ed Phillips by way of Terry Fritz <teslalist-at-qwest-dot-net>" <evp-at-pacbell-dot-net>

Tesla list wrote:
 >
 > Original poster: "Mercurus2000 by way of Terry Fritz 
<teslalist-at-qwest-dot-net>" <mercurus2000-at-cox-dot-net>
 >
 > Hello, I was curious, I wound a medium size coil for experimenting and I
 > was wondering if someone could help me calculate the frequency for the
 > coil, the coil winding is 11.625 inches high 1662.375 turns of 34 gauge
 > enamel wire and the diameter of the coil 2 3/8 wide on standard PVC, if
 > anyone could give me just a estimate withouth having a topload I would
 > greatly appreciate it and can verify my calculations.
 > Mercurus

	I just ran a calculation using a simple Basic program I wrote a number
of years ago.  (I think I entered your values correctly.)  Here's what I
get:

fr = 426.4 kHz
cd = 4.54 uufd
L = 30686 uh

This is a simple program using one of Wheeler's approximations for
inductance and a curve fit to Medhurst's data.  I have found that, at
least for the coils I've tested, it gives results within a couple of
percent, better than I expected when I wrote it.

	Be interesting to see what others get.

Ed