[TenTec] grounding

[Gary Hoffman]

Right....the short wire, the one that is of zero impedance, may carry some
current.  This will NOT be an appreciable current since the station is
properly designed.  (Mainly an issue of balance.)  Thus the second, longer
wire will not carry an appreciable current at its operating point either.
Nor will the longer wire carry ANY current away from its operating
frequency, since it is shorted out by the short wire.

Since the short wire never carries any appreciable current, and since it is
much less than 1/4 wavelength in physical size, and since it is at ground
potential at both ends...it will be a pitiful radiator as well.  I'd not
expect it to do much radiating at all regardless.

This allows me to have RF grounding...and lightning grounding, and safety
grounding...all in one nice package.


----- Original Message ----- 
From: "Martin AA6E" <aa6e at ewing.homedns.org>
To: "Discussion of Ten-Tec Equipment" <tentec at contesting.com>
Sent: Wednesday, January 10, 2007 9:18 AM
Subject: Re: [TenTec] grounding


> The question is whether your "ground" wire carries an appreciable RF
> current.  If it does, and if its length is a significant part of a
> wavelength, it will radiate.  There's no avoiding it.  Your "zero
> impedance" tuned ground will still be carrying current.
>
> If your antenna is balanced so that the ground wire does not carry an
> appreciable current (in Tx), then you may not need it for RF purposes.
> It may still help in a marginal situation, but your AC/lightning
> protection ground may be good enough.
>
> 73 Martin AA6E
>
> Gary Hoffman wrote:
> > 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 at ewing.homedns.org>
> > To: "Discussion of Ten-Tec Equipment" <tentec at 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
> >> _______________________________________________
> >> TenTec mailing list
> >> TenTec at contesting.com
> >> http://lists.contesting.com/mailman/listinfo/tentec
> >>
> >>
> >
> >
> > _______________________________________________
> > TenTec mailing list
> > TenTec at contesting.com
> > http://lists.contesting.com/mailman/listinfo/tentec
>
> _______________________________________________
> TenTec mailing list
> TenTec at contesting.com
> http://lists.contesting.com/mailman/listinfo/tentec
>
>