[Lowfer] Interesting finding

Tue, 7 Oct 2003 20:58:43 -0500

How about glass sheet and aluminum sheet and make a sandwich out of it???
3/4" copper water pipe with a 1/2" copper water pipe wrapped in poly and
inserted inside the larger pipe makes a very tough variable cap. Mine took
over 5000v AC & DC without even any ozone created.

Mike>WE0H

-----Original Message-----
From: [email protected] [mailto:[email protected]]
On Behalf Of Bill Ashlock
Sent: Tuesday, October 07, 2003 7:54 PM
To: [email protected]
Subject: [Lowfer] Interesting finding

Jay, and others,

I was checking out some resonant capacitors for the Medfer loop tonight on
the bench and found that my faithful silver mica caps aren't so faithful at
1.7mHz, after all.

Just for the heck of it replaced my reference 810pf, 500v cap with a
paralleled small 470p and a 330p that I found laying on the bench. The Q of
the test loop improved noticeably! Then I made up a combo of four small 180
and 220s micas that totaled about 800pf. The Q was even higher. Now it
really gets good: I replaced the micas with three tiny paralleled 270pf,
50v, COG ceramics and the Q increased by almost 20%!

I could never seem to reach the calculated the Q for the test loop (8T, 1/4"
tubing, 8"diam), or the outside loop, so the capacitor must be a good part
of the reason. Figure I need an ESR of about a 0.02 ohm and I don't think
micas can do that, at this freq.  Suppose I'll have to build my own
capacitors even though the power is only .1w!!  Ideas?

Bill A

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