Re: Standards for ground measurement

There are several methods for determining ground constants (conductivity
and permeativity) for use in modeling antenna performance. Among these
are measuring the tilt angle of the propogating ground wave and relating
it to ground constants using the curves on page 697 of Terman's
Radio Engineers Handbook, McGraw Hill 1943. A second method developed by
George Hagn at SRI (Washington Office) uses an open wire transmission line
probe. A third method is to measure field strength vs distance from a
simple monopole radiator and compare the curve to the calculated values
using Norton's equations.

Hope this helps,

Bill Vail
WAVE Associates, Inc.
Fulton Md.
wvail_at_ari.net

 On Fri, 8 Dec 1995 mcduffie_at_hannibal.wncc.cc.ne.us
wrote:

> Please excuse if this has been recently discussed, but I am very new (just
> now) to the list. Someone suggested this might be the place to post this
> question.
>
> In various places, I see maps giving very general ground conductivity
> estimates. In checking with my local power company, I've found out how they
> test grounds. Their desire is to test an existing electrical ground at a
> given location. Therefore, their tests are done between three points. One
> point is the site electrical ground rod(s). The other two points are provided
> by them. Two 4 foot rods are driven into the ground 75 feet either side of
> the site ground being measured. The two 4 foot rods are tied in parallel to
> one side of a megger. The other side of the megger goes to the existing
> ground. The resistance is checked at 500vdc. I understand how to convert
> this to Siemens/meter, but I wonder about the method of testing for MY
> purposes (antenna modeling).
>
> Is there a more standardized method of testing ground conductivity? For my
> own purposes, I would think that driving the two rods into the ground and
> measuring between them would be more useful. If so, how much rod, how far
> apart, and at what voltage should the test be run? I'm also assuming this
> should be done in a couple of places in the desired area, in order to be more
> accurate.
>
> Any help with the above would be appreciated. Thank you!
>
> Gary McDuffie, Sr.
> Scottsbluff, NE
> mcduffie_at_hannibal.wncc.cc.ne.us
>
>
Received on Fri Dec 08 1995 - 17:12:00 EST