On Fri, 16 Jul 2010 02:37:18 -0400, Roger
wrote:

On Tue, 13 Jul 2010 10:52:14 -0400, John Ferrell
wrote:

I don't remember the sources but I have concluded that the Grounding
wire should be no smaller than #6.

#6 is a minimum required by code here in the Midland MI area. As it's
a minimum, I would not use anything less than #2 Copper.

More than 8 feet of ground rod is of little consequence.

That depends on your soil conditions. Here I'd probably agree as the
soil is usually quite moist and just a couple feet down is just plain
wet.

However a string of ground rods tied together can be quite effective.

All ground rods should be tied together. Don't put your house between
two electrodes!

I'd put a circle of them around the house, all tied together every
16', but due to the garage and driveway, that is not possible.

The ground rods are better directly under the structure that they are
protecting.

I have a 100' 45G 10' from the NW corner of the garage. Tied into it
is a grounding system consisting of 32 or 33 8' ground rods connected
together with over 600 feet of bare #2.

This system consists of a ground rod about a foot outside the concrete
bare in like with each tower leg. The cable is clamped to each tower
leg and comes off in a curve to the ground rod and is extended out in
a straight line at least 80' with additional ground rods every 16'
(give or take a tad) This system also ties into the house electrical
ground. There is an additional run that goes directly from the ground
rod at the base of the 45G to the 25G on the West end of the shop.
From there it goes on around the shop to the mast holding the 144/440
vertical and around the south side to enter the shop to provide
grounding for the station and computers. This also ties the shop
ground (which is on a different electrical feed) to the house ground.


The system does not absorb massive high energy strikes. It starts
bleeding off the energy before the strike builds and thus minmiizes
the effect.

Mine has taken at least 17 direct hits that have been visually
verified. All that energy had to go some where.

The bleeding off theory has been pretty well discussed and discarded
on the tower talk reflector. Read up on the Polyphaser site. They have
some good information. Those lightning balls or porcupines have
proven ineffective. The major work for lightning rods and ground
systems is to divert the lightning away from the interior of buildings
and process control systems in Industry.


Home improvement stores sell #6 wire, ground rods and connectors.

Read the new NEC code for tower and antenna grounding. There is a
reason I went with #2.


On Mon, 12 Jul 2010 21:21:24 -0700 (PDT), Tom Horne
wrote:

Can anyone make a recommendation, based on actual training and
experience, as to what width and thickness of copper strap would be
needed as the down conductor from the antenna mounts at the peak of my
house roof, some twenty five feet above local terrain.

I agree with the #2 recommendation. OTOH there is nothing that will
protect an installation from the big atypical Positive lightning, or
super strikes. That's the stuff that blows holes in airplanes.

I have a a
mount for an antenna at one gable end and a mount for a weather
station sensor array at the other. What thickness and width should I
use in the earth between the two Grounding Electrode Systems. I will
drive five eighths inch copper rods, each eight feet long as far out
from the foundation as I can get them or eight feet were possible. On
one end that will be only six feet due to the proximity of the
property line. At all of the other rod locations I will be able to
keep them at least eight feet from any underground obstructions. To
compensate for the proximity to the foundation wall to the first rod
I will use rod couplers and drive it to hard rock or sixteen feet
whichever comes first. I'm guessing that in keeping the remaining
rods at least eight feet out from the foundation and sixteen feet
apart that I will only have four rods total in a ring around the back
side of the house. What is the best way to attach the copper strap to
the support masts and eve brackets themselves? Do you know of
anything that will make a good connection to the one inch galvanized
iron pipes that I'm using for support masts?

Can you recommend a technique for bonding the interior grounding buss
at the operating position to the exterior vertical copper strap. I
have no idea how that is usually done.

The Polyphaser site has a tutorial on grounding tower legs and coax
shields. this would be applicable to connecting to the 1" pipe.
Use lots on NoAlox between the strap and pipe.

73

Roger (K8RI)

John Ferrell W8CCW

Roger, I like your response better than mine.

It sounds to me like you have the ultimate solution. I arrived at my
operating point one step at a time and I quit working on the problem
when I quit having problems!

I have a non-Ham friend that lives a couple of miles down the ridge
from me that continues to have lightning related problems that may
benefit from your advice. I will pass along the Wisdom.

Thank you!
John Ferrell W8CCW