[TowerTalk] Ground Rods

Tom Rauch w8ji at contesting.com
Thu Apr 29 11:18:01 EDT 2004


> Someone mentioned that ground rods do not necessarily hv
to be implanted
> vertically. They can be installed horizontally in a
trench. But the depth of such
> placement was never addressed.

I'd never trust a shallow horizontal ground rod as a
lightning ground. Vertical rods in good soil make poor
enough grounds. A horizontal rod is really just a very short
radial, it isn't much for lightning or RF.

Why not look at polyphasors web site and see what they say?

The minimum I'd do is a large grid of reasonable size solid
copper bare wire  like #6 or #8 with multiple short rods.
What I have done is use multiple (I mean a dozen or so)
copper pipes spaced some distance apart with wide copper
flashing laid over the top. I punch holes in the flashing
and fit the pipe through the holes, and drive the pipe down
to the rock and cut the remainder off. Then I silver solder
the pipe to the flashing and have radials leaving the
flashing also. You need a lot of contact area! I've found
that effective where there is rock below a few feet of soil.

The most important thing is a perimeter ground around your
house, and bringing all the cables and station grounds to
the utility company ground with very low impedance
connections. Even if you can't get a good ground, at least
everything will try to come up together. The last thing you
want are ground loops through the house. That's what will
really tear things up.

73 Tom




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