[Elecraft] Station grounding question

[W3FPR - Don Wilhelm]

Glenn, Bob and all,

What constitutes a good utility ground or a protective lightning ground will
not always (you can substitute usually) provide an effective RF ground.  See
Vic Rosenthal's posting today on this same subject.

For example: Consider that a good RF ground can be provided by a properly
tuned counterpoise wire - an electrical 1/4 wavelength long and open at the
free end (just like half of a balanced dipole) and separated from earth
along its entire length.  The near end will present a low impedance at the
frequency the wire is tuned to and thus presents a good RF Ground.  This
near end can be (should be) attached to the tuner (or transceiver) grounding
point to provide the RF ground - THE CHASSIS SHOULD ALSO BE CONNECTED TO THE
AC MAINS AND LIGHTNING PROTECTIVE GROUND at the same point.

The point here is twofold: 1) Each type of ground will have different
characteristics, and 2) An RF ground need not have any relationship with
what we normally conceive as 'ground' - the British commonly use a separate
word - 'earthing' which I believe helps keep the distinctions separate and a
bit closer to correctness - earthing is good for AC, DC and lightning
grounds, but may or may not have any relationship to an RF ground.  I doubt
that a Ufer ground would serve as a good RF ground, although it may do so at
some particular frequencies - I would want to test it before depending on
it.

73,
Don W3FPR

> -----Original Message-----
>
> Hi Glenn
> Seems a lot of work for a relatively simple rf ground.
> Why not just take a piece of copper tubing and lay it in a shallow trench
> and bond your ground wire to it?
> RF doesn't penetrate the ground very far, so a deep trench wouldn't be
> needed.
>
> Glad to see you're still around.  Haven't heard you on in a while.
> 73, Bob N6WG
>
> -----Original Message-----
>
> I recently up graded my house electrical panel from 100 to 200 amp
> service. In order to do the up grade I had to install a Ufer ground
> which was 20 feet of bare #4 copper wire in cement. Our local code
> allowed a 10 foot run of wire in a U shape in a 9 inch wide trench. The
> wire had to be 3 inches above the dirt 3 inches from the side of the
> dirt 3 inches between the wires and three inches away from the dirt on
> the other side of the trench. That allows for 3 inches of cement all
> around the bare copper wire. The more I found out about Ufer grounds the
> better they seem to be to me. The PH factor in the cement and the fact
> that the cement never completely dries out and retains moisture make it
> an excellent ground.
>
> This leads me to my question. Is anyone out there using a Ufer ground as
> a counterpoise or to ground their tower and station? This seems way
> better than the old ground rod pounded in the dirt. Any comments would
> be appreciated.
>
>
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