On 1/29/15 6:51 AM, Ed Sawyer wrote:
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".
This is why I sort of cringe when folks hand out links to the Motorola
R56 document or the FAA document and say "here's what to do for
lightning protection"..
That's well, well beyond what most amateurs need.
The other thing about commercial vs amateur practice is that the job
cost structure is totally different. Amateur self-labor is
out-of-pocket free (leaving aside opportunity cost, etc.).. Electrical
contractor labor is not. Amateurs have a reputation as excellent
scroungers and improvisors and collectors over the years of materials.
Electrical contractors buy their materials at current cost, today.
For a contractor to drive a half dozen rods and string another 30 feet
of copper wire and one-shot weld it is a small material cost compared to
the labor. They do not care all that much whether the drawing calls for
3 rods or 6.
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|