Always an interesting topic. I wanted to offer my opinions on this subject
for consideration:
The system has four purposes - 1) Static discharge to avoid a build up 2) an
efficient leader to attract the strike if its going to hit in that area 3)
Current dissipation of a direct hit 4) minimizing ground loop voltage
potential when nearby strikes turn what should be ground into a damaging
voltage carrier vs other assumed grounds on your equipment.
Personally for #3 - I take the strategy that on a ham's budget, we are never
going to do a good job at a major strike. I am just going for not exploding
the tower base. So I put 3 ground rods in the hole itself with direct
connects at the bottom of the buried base section. So that at least there
is no concrete path of choice to ground on a direct hit. Beyond that I
assume the ground itself will dissipate the energy just like any other
forest strike.
Number 1 and 2 are really executed the same way which is accomplished by a
rod at the top of the mast and a direct connection of the mast to the tower,
rather than "through the rotor". This is meaningless for a hit which will
for sure fry the rotor but helps discharge and leader efficiency.
Number 4 is really where all the payoff is and it's a system of ground
points both in the tower area for tower hanging electrical items, at the
entrance to the house, and a grounding system in the shack. Number 4 is
actually the most utilized need in my experience. At this QTH, I have had 6
strikes of note in 10 years. 1 was a direct hit on my shortest tower
(proving other points), 1 was an energetic leader that did not result in a
direct hit but blew out coax on the 30 ft EU 10M antennas that decided it
wanted to be the leader that day, and 4 (or more actually) have been close
ground strikes that have seriously affected ground potential not equaling
zero volts.
I admire the survivability and reliability demonstrated by a nearby cell
tower installation that I hike up to at 2600ft (my QTH is at 1200 ft and yes
it does cut off my Pacific low angle stuff). But when I see the money put
into the hardline, grounding, and equipment shack at that installation, it
quickly becomes apparent that duplicating that "ain't gonna happen".
73
Ed N1UR
(I actually am an antenna engineer but I don't play one on TV nor practice
the profession directly anymore)
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