Let's say for sake of discussion that you have a shack position close enough
to physical earth (and your array of ground rods and buried wire) that you
can have an excellent, much less than 1/4 wave ground, made of broad strap,
at all frequencies except 10 meters. So, for 10 meters, you use a tuned
ground strap centered where you normally operate. It seems to me that this
"longer" ground strap will not become a radiator at the lower frequencies
because it is in parallel with the real short strap, and thus is effectively
"shorted out" RF-wise by that short strap. Not so ? If one has several
impedances in parallel with a short circuit, is not the whole thing then a
short circuit ? And hence a zero (well, close to zero) impedance ground ?
73 de Gary, AA2IZ
----- Original Message -----
From: "Martin AA6E" <aa6e@ewing.homedns.org>
To: "Discussion of Ten-Tec Equipment" <tentec@contesting.com>
Sent: Tuesday, January 09, 2007 9:52 PM
Subject: Re: [TenTec] grounding
> M. Todd Miskel wrote:
> > Doesn't a good earth ground help remove stray RF from the shack? along
with
> > ferrtie cores etc...
>
> Ferrites can help, but if you really want a "good" RF ground, it should
> be less than about 1/10 wavelength long at the shortest wavelength you
> want to use. So about 3 feet in the 10 meter band!
>
> If it's not that short, it can be "tuned" to be an integral number of
> half wavelengths at any one particular operating frequency... but then
> your "ground" lead becomes part of your antenna system. It will radiate
> and receive.
>
> So it is good advice (as someone said) to be sure your antenna is well
> balanced and as far away from the shack as possible. In that case, the
> RF ground is usually not needed. But a good AC & lightning single point
> ground system is still important.
>
> 73 Martin AA6E
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>
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