[TowerTalk] copper or galvanized ground rods in red SC clay

[Grant Saviers]

Agree that RF design is the key AND low resistance is good.  Of course 
there are exceptions, but perhaps not common among ham installations.  I 
climbed several mountains in ME, noting the lightning "ground" on the 
top of one with a mostly bare granite summit.  There were no ground rods 
I could find, but there were a lot of cables in a mesh configuration 
over a half acre or so of granite.  I doubt there was a DC ground 
resistance anywhere near to ten ohms.  The mesh was the best they could 
do for lightning strike dissipation.  Probably would have a great corona 
show in a strike, but who would want to be there to see it?

Google earth shows a new tower on that summit, Boundary Bald Mt, ME.  It 
would be interesting to know the grounding system design. What is there 
had to arrive by helicopter.  One group climb I did on that summit had 
some folks arrive by JetRanger so I know there is a flat enough spot to 
very carefully land a 206.

Grant KZ1W

On 1/10/2016 10:48 AM, Jim Brown wrote:
> On Sun,1/10/2016 10:26 AM, Grant Saviers wrote:
>> "The resistance of the grounding electrode system is only a general 
>> measure of
>> merit. Proper design and installation of the grounding electrode 
>> system, installation of ground rings, ground rods, radial grounding 
>> conductors, and the bonding of systems and equipment, is as important 
>> as the resistance to earth." 
>
> This the most relevant statement in the several you have quoted. Think 
> about it -- many (most?) VHF/UHF communications facilities are located 
> on mountaintops, where the "soil" is largely rocky/sandy. Heroic 
> efforts are required to attain even a modestly low resistance to earth.
>
> At the height of the telecom bust, a colleague bought two 
> decommissioned AT&T Long Lines sites on mountaintops, and I had a 
> station in one of them for a while. I had the opportunity to study 
> AT&T's drawings for the building and for the grounding. Every detail 
> was noted; there are many earth electrodes, and there is extensive 
> bonding both inside and outside the building. This particular site is 
> on a 3,000 ft peak in NorCal, with a 2-story building that is 120 ft x 
> 60 ft and a 150 ft tower that is 32 ft x 32 ft at the base and 24 ft 
> square at the top. There's a photo on the W6BX qrz.com page, which I 
> shot from a wooden fire observation tower about one hundred feet 
> higher at the actual peak.
>
> 73, Jim K9YC
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