First change for longer sparks (fwd)
---------- Forwarded message ----------
Date: Tue, 07 Jul 1998 08:48:38 +0300
From: Marco Denicolai <marco-at-vistacom.fi>
Subject: First change for longer sparks
Thanks to everybody who answered my previous email. Among many suggestions a
bigger toroid seemed to be common.
So I replaced my toroid 3.15" diameter tube, 11.4" outer diameter, 12.7 pF,
with a toroid 3.93" diameter tube, 15.7" outer diameter, about 17 pF. The
resonance frequency dropped from 240KHz to about 195KHz and I tuned the
primary tap again.
I got less streamers breaking into air (about 5-6 at the same time, compared
to maybe 10-15 with smaller toroid). These streamers where max. 31" long
(before where max. 20" long).
Still (without using any sharp nail fixed on the toroid) I couldn't manage
to get discharges to a grounded point longer than 24" (compared to 20" before).
Please, recall that my tank supplies only about 6.5 KV (NOT a 14KV NST!).
Because my spark gap is a RQ static gap with blower and two series of 2 of
0.0275" gaps connected in parallel, I think my next step will be to go for
a RQ static gap with 7 mils gaps, to get better quenching and easier
tunability of the gap number.
Any comments or suggestions?
P.S. Yes, my sparks gap gaps are really 0.0275", not 0.275" as from my
previous email. Sorry, I lost one zero :)
Marco Denicolai Vista Communication Instruments, Inc.
Hardware Development Manager www.vistacom.fi
marco-at-vistacom.fi Kaisaniemenkatu 13 A
fax: +358-9-622-5610 SF-00100 HELSINKI
phone: +358-9-622-623-15 Finland
Remember, Murphy was an optimist! I am not...