Re: frozen ground ground

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

Original poster: "Jim Lux by way of Terry Fritz <twftesla-at-qwest-dot-net>" <jimlux-at-earthlink-dot-net>

Rather than fooling with plywood, get some chicken wire and lay it out on
the ground.

a) the chicken wire itself will make a fairly good RF counterpoise for the
coil, if the diameter is, say, twice the height of the top of the coil above
it. (3 foot high coil on a 3 foot high table, means highest point is 6 feet
above ground=> chicken wire should be on the order of 12 feet in diameter
(or, 6 feet in diameter on the table..)

b) The capacitance between the chicken wire and the "ground" will provide
sufficient RF path (do a quick calculation... 3 meter circle (about 10 ft)
is 7 square meters. Figure that the spacing is roughly 1 cm. C = 111 *
7/0.01 = 77700 pF= 7.77E-7F.  At 200 kHz, X = 1/(2 * pi * f * C) =
1/(6.28*2E5*7.77E-7) = 1/(.976) = 1.02 .... 1 ohm...  pretty low compared to
the resistance of the secondary itself, the ground resistance, etc.

I wouldn't obsess about making a perfect circle, connecting the wire to
itself, etc.  Just roll out a bunch of sections overlapping like a star.

For a real nifty storage/packaging approach, you could get a big piece of
scrap carpet and attach the chicken wire to the bottom.  That way, you'd
have a way to roll it up, to give a good visual cue where it is (i.e. where
not to stand..), etc.

----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Saturday, December 07, 2002 9:41 AM
Subject: frozen ground ground


 > Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<yinzara-at-mit.edu>
 >
 > I'm wanting to ground my tesla coil but because of the time of year, there
is
 > no way of driving a stake into the ground or even turning some earth to
put a
 > piece of flashing in. Also I don't know if the frozen ground would act too
 > well
 > of a ground anyway. How would you guys suggest I ground my coil? I was
 > thinking
 > about driving 20 or 30 really long nails into a piece of plywood then
 > connecting them all on the top of the board. I would then place that on
the
 > ground and jump on it or something to push into into the earth at least
some.
 > Does anyone think that might work? If not, do any of you have a suggestion
of
 > how I might ground the coil?
 >
 > Matt Morrissette
 >
 >