Jumping in with both feet?
From: Chuck Curran [SMTP:ccurran-at-execpc-dot-com]
Sent: Wednesday, January 28, 1998 4:51 PM
To: Tesla List
Subject: Re: Jumping in with both feet?
Welcome to the list and Tesla Coiling in general. I see Bert's
given you a complete reply so I'll simply wish you luck on your project!
From: Tesla List <tesla-at-pupman-dot-com>
To: 'Tesla List' <tesla-at-pupman-dot-com>
Date: Wednesday, January 28, 1998 12:00 AM
Subject: Jumping in with both feet?
>From: SBJohnston-at-aol-dot-com [SMTP:SBJohnston-at-aol-dot-com]
>Sent: Tuesday, January 27, 1998 3:48 PM
>Subject: Jumping in with both feet?
>Please allow me to introduce myself: Steve Johnston, in York,
> I'm 34, with 21 years as a ham radio experimenter and 15 years as a
>Broadcast Engineer (so I'm not a newbie to high voltage/current RF
> I've had a passing interest in Tesla coils for years, but never took the
>time to fully study the details and build a system. Over the past week,
>however, my interest has intensified greatly as I was fortunate enough to
>come upon a nicely-crafted TC whose owner had died (hopefully his passing
>not related to TC experiments!).
>This coil stands about 5 feet high not counting a top discharge terminal.
> The primary is made of 11 turns of 3/8" Copper tubing, spread about 12"
>high and 26" in diameter. The tubing is air-wound, held separated by
>(nylon?) spacers. The secondary is wound with about #22 wire around a
>cylinder of 1/2" wide varnished wooden strips spaced about 1/2" apart. It
>consists of two sections in series, each 2' long, about 3 inches between
>two sections, for an overall winding length of 4'. It is 16" in diameter
>with about 13 turns per inch. The secondary sits about 2/3 of the way
>the primary -- perhaps by design to set the coupling between windings?
>There is a dome-shaped metal cover about 8 " tall and 6" in diameter that
>probably intended to be a top discharge terminal. It could connect to the
>center contact bolt on the top of the secondary with a short length of
>The "exciter" (if that is an appropriate term?) is built into a metal
>and consists of a Variac driving a 15 KV 30 ma neon sign xfmr (half the
>winding is used, centertap to one end), a small series inductor, and four
>caps in parallel. The caps are of unusual physical design (to me) but not
>homemade -- the four together measure about 0.02 uF. The spark gap is also
>commercially-made with circular, D-shaped electrodes with cooling fins
> -- the gap is easily adjusted.
>Any opinions as to the capabilities of this rig? Would it be meaningful to
>temporarily short the spark gap and attempt to grid-dip the primary tank
>see where it resonates? Does the secondary self-resonate with distributed
>capacitance? To what spacing should I set the gap when I start testing?
>Am I asking too many questions? I guess I'm way too excited and eager to
>Thanks for any opinions and information!