Topband: ground characteristics

[Guy Olinger K2AV]

Figure out how to do that for a small lot backyard in an old European
village with 900 year old homes.

73,  Guy.


On Wed, Oct 3, 2012 at 3:59 AM, Jim Brown <jim at audiosystemsgroup.com> wrote:

> On 10/3/2012 12:35 AM, Bob Kupps wrote:
>
>> "It is impossible to make a direct measurement of ground characteristics".
>>
>
> Horsepucky.  Now, what IS difficult is to make a direct measurement to
> great depth!  But N6LF has shown a simple method to measure to the depth of
> whatever length of rod you are willing (and able) to drive.
>
> The "slope of the decay of field strength" method is a very good method
> for frequencies for which good data is published,  but to get good data
> you've got to take a lot of data points along a radial from the test
> transmitter site.  More than fifty years ago, I worked for a broadcast
> consultant who did that as part of his applications for new licenses in a
> band that had been full for 30 years. )  My job was to plot his data and
> extract the conductivity data.
>
> You could, for example, use this method with a local broadcaster operating
> near the high end of the AM broadcast band. BUT -- you need calibrated
> instrumentation to get accurate field strength measurements, and you need
> to make a LOT of measurements at a chosen azimuth that covers the area of
> interest along a line drawn from the transmitter to and past the area of
> interest.  You must then plot that data of field strength vs. distance,
> then compare it to FCC curves for that operating frequency, matching the
> SLOPE of your data to one of the several families of curves in the FCC data.
>
> This is NOT a trivial exercise!
>
> 73, Jim K9YC
>
> ______________________________**_________________
> UR RST IS ... ... ..9 QSB QSB - hw? BK
>