RE: RF grounding (fwd)

["Tesla list" <tesla@xxxxxxxxxx>]

---------- Forwarded message ----------
Date: Tue, 19 Jun 2007 14:47:45 -0400
From: "Lau, Gary" <Gary.Lau@xxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: RE: RF grounding (fwd)

Yes I agree that a coil's performance is largely (maybe completely)
unaffected by the quality of the RF ground.  I have heard reports on
this list where someone completely forgot to connect the secondary base,
and no difference in performance was noted.

But the reason that we use an RF ground is actually to prevent RF from
traveling through the AC mains, where damage to other appliances may
result.  Without a good RF ground connection to the secondary base, the
secondary base current will capacitively couple through the primary,
through the NST, and through the power cord to the best approximation to
a ground that the RF can find.

Regards, Gary Lau
MA, USA

> From: Tesla list [mailto:tesla@xxxxxxxxxx]
> Sent: Monday, June 18, 2007 10:00 PM
> To: tesla@xxxxxxxxxx
> Subject: Re: RF grounding (fwd)
> 
> 
> ---------- Forwarded message ----------
> Date: Mon, 18 Jun 2007 22:27:12 -0400
> From: Jonathon Reinhart <jonathon.reinhart@xxxxxxxxx>
> To: Tesla list <tesla@xxxxxxxxxx>
> Subject: Re: RF grounding (fwd)
> 
> RF Grounding.. hmm in my experience it is quite overrated.  Now don't
get me
> wrong, it definitely is necessary for optimal performance and safety.
But
> in my work with tesla coils it hasn't been an overwhelming difference.
I
> actually won my 8th grade science fair by comparing the operation of
tesla
> coils with and without RF grounds (connected at the base of the
secondary
> coil).  I will have to dig up the data, but in my results the
difference was
> relatively small.
> 
> When showing tesla coils, and running them in locations that you're
not used
> to, Grounding can be an issue.  No matter how tempting, don't connect
your
> RF ground to the third wire ground.  That can damage other connected
> electronics.
> 
> One time I had to run my coil inside a large room in the middle of a
house.
> To get a decent ground, I ran some #2 Aluminum service wire outside.
I used
> a simple hoseclamp to my standard ground cable on the inside, and
outside I
> just stuck the #2 into the end of a Cu pipe that I pounded only about
2'
> into the ground.
> 
> Good luck
> 
> Jonathon
> On 6/18/07, Tesla list <tesla@xxxxxxxxxx> wrote:
> >
> >
> > ---------- 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.
> >
> >
> >
> >
>