Date: Fri, 5 Feb 2016 11:56:22 -0600
From: Kelly Taylor <ve4xt@mymts.net>
To: dw <bw_dw@fastmail.fm>
Cc: TowerTalk <towertalk@contesting.com>
Subject: Re: [TowerTalk] Verticals and well pipe grounding
It seems as though their suggestion on using water pipe ignores that even in a
frost-free zone such as Hawaii you would want those pipes buried enough to
avoid incidental damage, which I?m guessing is also enough to be beyond the
skin effect of the earth surrounding them. In an area with a known frost line,
those pipes are probably buried even deeper.
Now, a network of pipes buried like they?re suggesting might be a good safety
ground, since if they?re metal, they?d have lots of contact with earth spread
over a large area.
If they?re suggesting well pipe, that would be about as effective as a single
ground rod. In other words, not very.
It also seems to fall into the trap ?well, if it worked here, it must work
there.? Happening upon a workable antenna does not mean it?s a repeatable
design.
73, kelly, ve4xt,
## at the telco I worked at for 34 years... the normal deal was a series of
10 foot copper grnd rods around the perimeter of the building....all bonded
together with 2 inch wide, thick cu strap...and the entire mess buried below
grnd. On the roof top microwave towers, they would run a single 3 inch
wide, very thick cu strap, from base of tower, to over the side of the
roof..and straight down to the buildings ground system.
## On ground mount towers, free standing or guyed variety, 10 foot ground
rods would be jack hammered into the bottom of the tower hole, and cadwelded.
Then other end of the 00 cu wire would be bonded to the base of the
tower..which sat at the bottom of a very deep hole. The idea here is to get
the rods well into the ground..and below the frost line. At the 54 deg
latitude where I was from 1979-1989....the frost line could be very deep..esp
with low temps like –17 dg C. In other places of BC it was worse..with temps
like -40 deg C.
## On a similar note the spec was for 2 ohms or less. At one of the sites
near a lake, the ground condx were lousy. So they had a 450 ft deep hole
dug...and in went a 450 foot solid cu strap.... completely surrounded by
carbon granules. Think it was aprx 6-8 inch diam hole. You don’t even
wanna know how much that cost ! It was not installed for lightning protection
either, since no towers or any ants at that location, it was just a small
switching office.
## at one of our mountain top microwave sites....up on solid rock, they used
hundreds of 10/8 gauge solid wires, just like radials..laid out on the rock,
several hundred feet long..each. The remote site...helicopter access only....
got hit by lightning real bad one spring...and the entire site burnt to the
ground, diesel tank caught fire, etc. The radials were burnt to a crisp,
just charred remains. Another gong show to fix.... including airlifting
concrete to a remote site, and ditto with buildings, new tower, new ants,
heliax, wave guides, diesel gen sets,etc.
Jim VE7RF
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