[TowerTalk] Clamp on ground resistance meter

[Grant Saviers]

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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