[TowerTalk] Verticals and well pipe grounding

[Jim Thomson]

Date: Fri, 5 Feb 2016 11:56:22 -0600
From: Kelly Taylor <ve4xt at mymts.net>
To: dw <bw_dw at fastmail.fm>
Cc: TowerTalk <towertalk at 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