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RE: [TCML] Counterpoise Insulation from Ground



Gary 
I can see your thinking behind that. When I last used one on a wooden floor
at a teslathon (with the RF earth connected to it), my thinking was that
there would be a clearly defined capacitance between the top load and the
counterpoise underneath, rather than an uncertain one with the wooden floor
and the earth somewhere beneath that.
However I also ran a wire outside and connected an external ground earth to
the counterpoise as well.  [Strictly speaking I suppose it is not a
counterpoise in that situation?]  The addition of an external earth I
thought, would help to simulate normal conditions and encourage ground
strikes as well as air streamers. 
I tuned the coil with a scope as well and there was a slight change in the
resonant freq of the secondary as a result (toroid is about 6 feet above
ground)

There is a picture of the 'counterpoise' being constructed  (around half way
down the page) at this site
http://www.extremeelectronics.co.uk/gaussfest2010/index.php  
Regards
Phil

www.hvtesla.com

-----Original Message-----
From: tesla-bounces@xxxxxxxxxx [mailto:tesla-bounces@xxxxxxxxxx] On Behalf
Of Gary Lau
Sent: 28 November 2010 00:35
To: Tesla Coil Mailing List
Subject: Re: [TCML] Counterpoise Insulation from Ground

Hmmm.  RF grounding is one of those things that I don't have a firm grip on
in my mind, but if I might think out loud...

Intuitively it seems like a good ohmic connection to the Earth is important
and would indicate the relative quality of an RF ground system.  But
consider for a moment the use of a counterpoise, which has no ohmic
connection to Earth.  Once again, intuition suggests that a counterpoise
sitting directly upon a moist concrete floor might be a better ground than a
counterpoise two stories up in a wooden structure, but I really don't know
(nor do I know how to find out).  It could be that it doesn't really matter?

Regards, Gary Lau
MA, USA

On Fri, Nov 26, 2010 at 12:07 PM, dave pierson <dave_p@xxxxxxxxxxx> wrote:

> A different aspect, as we head into that time of year when some of us 
> get Cold...
>
> If the ground around the ground FREEZES, the ground becomes less
> good:  Ice is a bad conductor.  If the ground rod goes deep enough, 
> effect is minimal.  If ground around rod(s) freezes all the way down 
> the 'ground' becomes isolated.  Once current is forced in, localized 
> melting may ease the effect...
>
> best
> New dwp:     dave_p@xxxxxxxxxxx
> _______________________________________________
> Tesla mailing list
> Tesla@xxxxxxxxxx
> http://www.pupman.com/mailman/listinfo/tesla
>
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