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Old October 2nd 07, 06:26 PM posted to rec.radio.amateur.antenna
Mike Kaliski Mike Kaliski is offline
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First recorded activity by RadioBanter: May 2007
Posts: 182
Default Ground rod lengths vs number


"Kenneth Grimm, K4XL" wrote in message
...
I'm installing a new tower and bought, as part of the package, the
grounding kit. This consists of four 10 ft copper clad ground rods,
plus all the accessories needed to connect them to the tower.

My problem is that after about 5 feet of good old red clay I hit solid
rock. I'm tempted to cut the 10 ft rods in half and simply have eight
5 ft rods. Since this is the only practical alternative that I can
see.

Will the eight 5 ft rods give me the same "ground" as the four 10 ft
rods? Or, do I need to add even more 5 ft rods to achieve the same
ground? ( I knew I should have bought that Megger at the hamfest. )

Opinions welcomed. Empirically derived evidence treasured! 8*)


Ken K4XL


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Ken

This very subject was covered at some length not so long ago. The consensus
was that solid rock does not make a very good earth. Driving the rods in at
an angle to get the full 10 feet under the soil is probably going to be
adequate. If you are concerned that the earth is not good enough, add some
lengths of thick, bare copper wire buried in the soil and conected back to a
common earth point. The rods are mainly there to provide a dissipation path
for lightning if it should hit the tower.

Mike G0ULI