[TowerTalk] Mot R36 related to NUMBER of installed ground rods

[john at kk9a.com]

I see how this works now, thanks.  Since it takes specialized equipment, I
wonder how many hams actually test their ground rods.

John KK9A

To:	towertalk at contesting.com
Subject:	Re: [TowerTalk] Mot R36 related to NUMBER of installed
ground rods
From:	jimlux <jimlux at earthlink.net>
Date:	Fri, 3 Nov 2017 08:05:34 -0700

On 11/3/17 7:15 AM, john at kk9a.com wrote:
How is ground resistance measured?


With an AC ohmmeter specifically designed for this application. Mostly, it's
a matter of standard probes, standard measuring voltages and currents, etc.
so that everyone's measurements are the same.

googling "grounding system resistance testing" turns up lots of links:

http://www.esgroundingsolutions.com/how-to-do-electrical-grounding-system-te
sting/
http://www.weschler.com/_upload/sitepdfs/techref/gettingdowntoearth.pdf
http://www.aemc.com/techinfo/techworkbooks/ground_resistance_testers/950-WKB
K-GROUND-WEB.pdf

there's a difference between measuring soil resistivity and grounding system
resistance, but the same kinds of measurement tools are used.

I'm sure you could use standard ham DMM and a variac + isolation transformer
to do something that is functionally similar.

The tricky parts are the standardized electrodes (that's just a matter of
getting the right length and diameter) and not having your measurement
perturbed by ground currents from other sources and interference. Kind of
like the problems with measuring an 160m antenna when there's strong AM
stations nearby.