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Group
For RF ground behind equipment in shack I am fortunate to
have a stick of copper buss bar salvaged from an overhead crane electrification
system. This bar is about 1.5" x .375" and allows me to connect short 14
gauge wires to equipment ground lugs. That bar is connected to earth rod right
outside shack thru a length of 4ga copper wire. If I didn't have the buss bar I
would use copper pipe or 4" flashing material, both reasonable cost for what is
involved.
The outside rod isn't really a rod but a length of 3/4"
copper pipe which I capped the end and drilled small holes around the cap.
Connect the top end to the garden hose and drill it right down in the earth.
More than one would be better but one is better than none. This rod is far
superior rod to those copper plated steel rods that are half deteriorated before
they get in the ground. Also, I thought it interesting that in all the
discussion on ground rods (electrical or rf) did anyone mention that they
are to be installed outside of the drip line of the overhang of the building?
The Utility will call you on that here if it isn't.
This summer I am going to attempt to bury a
counterpoise system under the antenna(s) and tie that to the rf ground rod. I am
going to try something different here. Instead of copper wire I will be using
aluminum locating tape that is typically buried with plastic pipe so it
can be located later. About $25 will get you 1000 ft of 5 mil thick tape with a
mylar(?) covering. This will last a lifetime, it is fairly rugged for
installation and provides 48 sq inches per foot of surface area (total of both
sides of 2" wide tape). I've never heard anybody try it for that but it makes
sense to me.
Now, all that talk about improving grounds and antennas
for optimum performance of the Collins equipment brings me to ask for help
locating, dead or alive, a probe for my HP 4815A rf vector impedance meter. I
sure would like to add the instrument I have to my arsenal but for lack of
a probe, or even the connector for same, the battle is lost. Anyone able to help
me on that?
Regard
Paul K0UYA
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