RE: RF grounding (fwd)

["Tesla list" <tesla@xxxxxxxxxx>]

---------- Forwarded message ----------
Date: Mon, 18 Jun 2007 09:37:11 -0400
From: "Lau, Gary" <Gary.Lau@xxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: RE: RF grounding (fwd)

> Date: Sun, 17 Jun 2007 20:59:21 -0400
> From: Scott Bogard <teslas-intern@xxxxxxxxxxx>
> To: tesla@xxxxxxxxxx
> Subject: RF grounding
> 
> Hey folks,
>      I have a question regarding RF grounding.  What gage cable would
be
> necessary for a 6-in coil.

The necessary gage probably depends on how long the cable is.  For
instance, if the ground rod was 6 inches away from the secondary base,
I'm sure there would be no problem in using the same narrow gage that
the secondary was wound with.  Longer cables would require
correspondingly heavier gage.  But I say this with my hands waving, as
there is virtually no hard data showing what is needed, or even what the
consequences of under-gaging (?) might be.  We don't even have a way to
quantify or measure the quality of an RF ground.  We simply do the best
that we can and hope for the best.

>  Can one use coper pipe instead of grounding rods
> (how many feet, how many rods, how deep).  

Copper pipe is just as good, electrically, but being so soft, you'd have
a hard time driving it through the earth.

> Can one use copper plated steel
> rods, or is pure copper necessary.  

Copper-plated steel ground rods are sold for this very purpose.  Thanks
to the skin effect, a copper exterior is all that's necessary.

> What does one do, if he has a
> particularly rocky yard, and pounding stuff in deep becomes a problem.

Typically one writes to the Tesla List to seek advice ;-)  

I have seen advice for your situation, advising one to use a copper pipe
coupled to a garden hose, with the water jet "blasting" a path through
the earth as the pipe is pushed downward.  Of course this won't help if
you have rocks.  I also wonder if this method results in the more
conductive silt being rinsed away, leaving just less-conductive rock and
gravel in contact with the rod.  It's unclear to me if the RF grounding
occurs by virtue of capacitive coupling to the surrounding earth, or by
resistive conduction.

I'd say try to use a copper-clad steel rod with a sledge hammer, and
give it your best - probably several attempts are needed.  A pair of
vice-grips and a hammer may be needed to back out of dead-ends.  Also,
it may be a prudent to call dig-safe, or at least be mindful of where
your utility connections run!

Regards, Gary Lau
MA, USA


> Thanks a heap.
> Scott Bogard.