[Elecraft] Re:Ufer Ground question

[David F. Reed]

Glenn Maclean wrote:

(much snipped by Dave)

> This leads me to my question. Is anyone out there using a Ufer ground 
> as a counterpoise or to ground their tower and station?

I have been for the last 12 years or so; I highly recommend them.  In my 
installation, it approximates a commercial station I toured prior to 
starting construction.  Some notes:

   1. in setting all the rebar for the foundation, as it was tied, and
      before the concrete was poured, all the points at which the rebars
      touched each other  were cad welded (I think this is the term but
      it has been a while); the process uses little molds that are
      filled and then fired, resulting in a corrosion free weld (no
      oxide in between) huge "cage" that is in the concrete, similar to
      your normal rebar structure as far as structural strength, but,
      electrically bonded.  This is apparently capacitively coupled to
      ground (fairly low inductance as well).

   2. the advantage for lightning strikes seems to be that the whole
      ground system floats and then drops back down, so there is little
      differential (ground loop currents) so most stuff in the house is
      better protected.

   3. My tower (its base is part of the Ufer ground) has an excellent
      counterpoise from it; I have 70' tower, with a 8 element LP for 20
      - 17 - 15 - 12 - 10, and a 6 el. Yagi on 6 M.;  a full wave loop
      on 60 M, and an inverted L on 80 and 40, and a 160 - 10 M. B&W
      wide band dipole set for NVIS.  They all appreciate the better
      ground it offers.

   4. the cable entry to the shack (feed lines, coax switch, rotor
      control, etc.) all come in at a common entry point with all
      shields grounded prior to entering the shack, common ground, etc.

   5. I have taken several direct strikes (on top of a hill; all the
      trees in my yard have evidence of having been hit sometime); the
      first one was sufficiently strong that it took out a cable TV
      distribution amp 50 yards away that was buried - it took out the
      AC compressors, (lightning jumped to them as a supplemental path
      to ground?), the telephones, and the burglar alarm, but almost
      everything else in the house survived it by floating with the
      changing ground.  It even blew a chunk of concrete out of the
      tower base, where the rebar was too close to the outside of the
      concrete, and some water had gotten in, becoming superheated
      steam.  That chunk weighed over 20 lbs, and it went over 50 yards
      away (unhappy neighbors).

      I am convinced (and more importantly, so is the xyl) that without
      it, the house would have burned for sure.

We are building another home, but it is in an area with the dreaded C&R 
stuff, so no tower; we chose not to do Ufer grounds there, but I wish I 
had; I now figure I will have to run a ground wire under the long wire 
antenna to help it out...

(and, yes, the search is on for about 10 acres so I can get a 
competitive 160 and 80 meter array with a good ground going.)

> This seems way better than the old ground rod pounded in the dirt.

Definitely way more expensive too, but seriously better in terms of both 
an RF ground, and lightning protection.

> Any comments would be appreciated.
>
> Glenn WA7SPY
> Sacramento, CA 

73 de W5SV, Dave

-- 
David F. Reed  - W5SV -     cell: 512 585-1057