The loop you want to measure is the single rod through the earth to
multiple rods or a very low R ground such as a building Ufer.
Start with two rods connected with a wire, put the meter on that wire,
measure R. The assumption is that each rod has a resistance of R/2.
When you install the 10th rod the assumption is that the nine already
placed, connected together, and connected by a single wire to rod #10
have a much lower parallel resistance than the new rod. Of course there
is some residual error, but if you go back and measure them one at a
time, one against nine, you will get close approximate resistances of
each rod. Then these values can be computed as parallel resistances for
a close approximation of the net ground field resistance.
This is why a star layout of rods and connecting wires that looks like a
vertical antenna radial field is easy to measure, one rod at a time.
OTOH, if you have a perimeter wire, the meter will measure the wire
resistance of that loop.
Plus such a layout is the way to minimize the paralleled inductance.
Grant KZ1W
On 10/2/2019 11:59 AM, Wes wrote:
Hmmm.. Every other reference I see about using one of these says that a
loop is required.
On 10/2/2019 11:00 AM, Bryan Fields wrote:
On 9/29/19 2:51 PM, Julio Peralta via TowerTalk wrote:
Does anyone have any experience using a clamp on ground resistance
meter?
Yes, they work well.
I bought one to use to help with my grounding project but don't have any
experience using this type of meter. Any advice would be appreciated.
Ensure it's calibrated every time you use it.?? You should ensure it's not
measuring a loop, that will give errors.?? Single point or off a master
ground
bar feed is the right place to measure it.
I have this model:https://www.amazon.com/gp/product/B01N7FSF6N
Was a steal for 300 dollars.?? I've used it at my home and numerous
sites to
ensure the building ground is sufficient.
73's
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