Jerry Sevick, W2FMI, has an interesting comment about the "120" number in
his book, "The Short Vertical Antenna and Ground Radial." At the end of
the first chapter he notes:
"...it should be mentioned that the world standard for the number of
radials to be used with verticals in the AM broadcast band is 120. This
number was based on the classic paper published in 1937 by Brown, Lewis,
and Epstein. During the course of a business meeting with Dr. Brown, I
asked him how he and his colleagues arrived at the 120 radial
figure--because I was quite sure 100 would work as well. His answer was
interesting.
"He said that he and the others had been thinking in terms of 100 radials,
but the farmer who plowed in 100 radials had wire left over because copper
is soft and stretches easily. When he asked what to do with the extra
wire, the farmer was told to plow it in. The result was a world standard
of 120 radials."
Hmmmm!
Brad, KV5V
On Thu, Feb 13, 2014 at 7:49 PM, Tom W8JI <w8ji@w8ji.com> wrote:
>
>
> I understand that 120 radials is the golden standard. At what point is
> there no significant improvement?>>>
>
> 120 radials never was a gold standard.
>
> The FCC said if a AM BC station uses something like 110 radials, I forget
> the exact number, they can avoid doing a radial system proof of
> performance. I think Hams assumed that somehow meant 110 radials or
> whatever the exact number was were somehow "perfect".
>
> There is no improvement here on 40M at about 20-30 radials. YMMV.
>
> This will be different on different bands at the same location, and
> different on the same bands at different locations, and even different with
> different antennas. So what happens in one cause is probably not true in
> others.
>
> Read carefully, and you will see even Rudy Severns says that, so his gold
> standard isn't gold.
>
> 73 Tom
>
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