[TowerTalk] single point ground

[Jim Jarvis]

Dave, N7DRK wrote:

I am in the process of building my station at a new QTH and have a question
about the single point ground.
I will initially be installing a Steppir on a Trylon 70' tower which is
about 170 feet from the proposed shack.
The shack will be in a walkout basement room. The entry panel will be
outside of this area.
The house is serviced with underground power and phone. The nearest utility
pole is about 800 feet away. (above ground)
The utility power entry is located about 65 feet away on the opposite end of
the house from the shack. The utility uses a UFER ground.

How should I tie/route the utility ground to my single point ground. Does
the tie wire need to be routed outside and buried or can it be run through
the structure or a combination of the two? (concrete driveway and sidewalks
in the way outside)
-0-

As I see it, Dave, there is no way to have a 'single point ground' in the
system you describe.  But you can significantly improve on the 'distributed
ground' situation, minimizing differences between ground potentials during
a strike.

*  Provide a really good RF ground at the tower base, and again at the RF
service entrance.
*  Tie the power ground to the RF ground, at the RF service entrance.
*  You COULD do this with a perimeter ground, around the house, or by
	using strap to tie electrical ground to the RF service entrance.

My place in Vermont was much like yours, and what I did was tie the power
ground
and RF grounds together at the RF service entrance.  I had 8' ground rods in
both
locations.

Since you're in the basement, you COULD drill through the floor, and sink a
ground rod, right at the back of the station, 3 or 4' from the radios.

It would help minimize the problem, if you were to use a wireless internet
link
to your computer, so it wasn't attached to the phone or cable system.  That
way,
you would only have to worry about differences between the RF and power
grounds,
at the station common point, and with some effort that could be reduced to a
3 or 4'
run.

N2EA/Jim