[Lowfer] Beverage ground question

[Stan]

Hello John,

Yes, quite interesting. Reasonably small variation. I also suspect the 
water content.

The only way, I can immediately think of, to qualify this effect, is to 
continuously monitor the
earth to electrode system resistance, before, during, and after a rain 
storm.
Would be nice to monitor rate of rain fall or total rainfall.

Can you vary the frequency of the test ? Some testers like a hand crank 
Biddle
can vary the freq according to the speed of cranking.  If there is 
inductance in the system
the impedance will vary. If only resistive, the resistance (impedance)
will be the same for any test freq, or cranking speed.
Less inductance the better, for a lightning protection system and an RF 
ground.

Other ground testers like the Associated Research  Vibroground unit uses 
a mechanical multivibrator
and batteries to set the test freq. More modern solid state units are 
probably much more freq stable.
Just saw a Vibroground on ebay, for 1$, with no bidders, was a 3 wire 
tester.
Really obscure test equipment, Who does ground testing today ???
Vendors: Biddle, AEMC, AR...

Is your earth electrode system in a triangle configuration or in line ?
Probably would not matter because of the very decent separation.

Stan, W1LE   FN41sr   Cape Cod




John RABSON wrote:
> On 26/12/2007 at 17:05 Stan wrote:
>
> [ ... ]
>
>   
>> As an exercise measure your ground rod system resistance in the summer
>> and then compare to winter conditions.
>> A good system will have the same resistance in all seasons.
>>     
> You might find the following of interest.
>
> The ground rod system here consists of three 4 foot rods 20 feet apart in at least 10 feet of sandy soil, underneath which is limestone/granite.  Over the past 2 1/2 years their combined resistance has varied a little (measurements at 980Hz):
>
> Q2: 22 to 27 ohms
> Q3: 20 to 23 ohms
> Q4: 23 to 31 ohms
>
> No figures for Q1.
>
> I suspect the variation is related to rainfall, but I have no firm information on this.  Would anyone like to comment, please?
>
> 73
> John F5VLF
>
>
>
>
>
>
>
> _______________________________________________
> >From the Lowfer mailing list
> Send messages to: Lowfer at mailman.qth.net
> To sub/unsub visit: http://mailman.qth.net/mailman/listinfo/lowfer
>
>