John Brosnahan wrote:
>At 10:37 AM 4/16/97 CDT, you wrote:
>>A short time ago someone indicated they had measured the resistance
>>on their ground rods. How does one do this? Can it be done with
>>something as simple as a digital volt meter? What two points do
>>you measure between? I don't live in a particularly sandy area but
>>have no idea if my ground rods (6) will actually help if lightning
>page 27-35 of the current editon of the ARRL Antenna Book
>shows how to build a very simple system to make the measurement.
The important thing is to make the measurement using AC, becasue
electrolytic polarization effects make DC measurements impossible.
(Re another posting, meggers come in two flavors: you need the low-
resistance type made specially for ground resistance measurements, not
the high-voltage type made for insulation testing.)
The system in the ARRL Antenna Book is based on the power utility and
telco method for measuring ground rod performance, but it has been
adapted for measuring ground conductivity, which isn't quite the same
thing. The NEC may give more details on the standard method and the
precautions necessary to obtain accurate results.
73 from Ian G3SEK Editor, 'The VHF/UHF DX Book'
'In Practice' columnist for RadCom (RSGB)
FAQ on WWW: http://www.contesting.com/towertalkfaq.html
Administrative requests: towertalk-REQUEST@contesting.com