----- Original Message -----
From: John E. Cleeve <g3jvc@jcleeve.idps.co.uk>
To: 'Stone, Gary R . ' <Gary.Stone@va.gov>
Sent: Thu Jun 8 14:34
Subject: Fwd: Re: [TowerTalk] Ground resistance
Hello Gary,
I asked the same question. The answer was that the measurement device
cost around 1400 pounds sterling, so I decided to ask a company that
specialised in installing lightning protection for church towerers
etc. They came to my house and measured the ground resistance by means
of a bridge type meter, putting out test leads around the site etc.
They came up with a reading of 19 ohms, between my own "earth rod",
and the site boundarys, and said that figure could be improved on. I
agreed that they should continue the work, and they proceeded to drive
three copper ground rods into the soil, using a Kango hammer, at the
corners of an 8ft triangle, where my tower base is in the centre of
the triangle. They measured the ground resistance as each length of
copper went down, and once the three ground rods were driven to a
depth of 4 metres, the measured ground resistance was just 2.1 ohms, I
saw the meter reading, and I have a certificate to prove it. The
surface ends of the copper rods were then tied together, using 1 inch
wide, thick copper strap, and the top of my crank up tower, connected
to this ground system by means of a flexible copper conductor of an
equal cross section. The entire job took about 1 hour, and the cost,
about one third the price of the test equipment required to do the
measurement......I hope this may be of some interest to you and the
group....sincerely,
John. G3JVC.
On Wed Jun 7 19:09 , 'Stone, Gary R.' Gary.Stone@va.gov> sent:
>Greetings,
>
>
>
>I imagine I have missed the obvious but my question is how do you
>measure ground resistance? Does it take a special meter (I suspect it
>does). I am writing this in reference to ground rods and grounding of
>towers.
>
>
>
>Thanks,
>
>
>
>Gary, N5PHT
>
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