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Re: RF Ground, House Ground, Ground....



Original poster: "Justin Hays by way of Terry Fritz <twftesla-at-qwest-dot-net>" <pyrotrons2000-at-yahoo-dot-com>

Hi All.

> I dont think that 6-8" is nearly enough.  Im cutting it short with
> 2 feet with my RF gnd, and i have 4 rods in the ground.  My 
> secondary never arcs to my primary at the base, so that is a good 
> sign. I always thought that people put them in about 5feet or so 
> into the ground.  I hope that you are not running a large coil off 
> of this small RF ground.
>
> Steve Ward.

It doesn't matter. You will notice very little difference in
performance with a single 3 foot ground rod vs. several 5 foot ones
tied together with 3" bar stock.

The exception is if you live in very dry or sandy areas, where
resistance of the Earth is abnormally high. In that case, I can see
putting lots of effort into the grounding system.

My best bud and I ran our 12" coil at 18kVA many times with a single
4 foot ground rod. Then we clipped the ground lead to the fence that
ran around our entire backyard to see what would happen. The fence
was your typical cyclone variety, metal poles every 8 feet. Average
length of the entire structure is about 300 feet long, and the ground
is always wet here in extreme South Texas. So we're talking dang near
a perfect ground.

There was no noticeable difference in coil performance before and
after the ground was clipped onto the fence. Same arcs, 10-11 feet or
so.

I've noticed the same thing with every Tesla Coil that I have
designed and made, over 25 of them. Ground matters very little when
it comes to sparklength.

> My secondary never arcs to my primary at the base, so that is a 
> good sign.

That has everything to do with electrostatic field shape, input
power, coil performance, and other things of more importance than
grounding.

If you're trying to kill radiated interference, grounding is a big
issue. But if your sparks are shorter (or longer!) than you expected,
I would tend to ignore the RF ground as long as it is reasonable. I
mean, a wire laying on the ground probably will not work.

Take care,

Justin Hays
KC5PNP
Email: justin-at-hvguy-dot-com
Website: www.hvguy-dot-com