[IRCA] field intensity drop-off an inverse function?

[Charles A Taylor <MWDXer@xxxxxxx>]

At 11:25 AM 7/5/2007 -0600, you wrote:
>Joe Miller, AB8YP wrote:
>
> > Question: if the limit is 100 microvolts/meter at a
> > distance of 30 meters, using the inverse square law,
> > would that be roughly the same as 3 watts at the
> > antenna?
>
>
>Field strength measured in V/m vs. distance from the radiator is a
>straight inverse, rather than an inverse square, isn't it?


>I'm probably wrong, so maybe somebody who knows could explain field
>strength measurements....

Mike Los Alamos Almost,

Been downloading Part 73 of FCC R&Rs in PDF format. Lot to download,
and I do a couple/three chapters a day.

I'll get to the field intensity/vs/distance/vs/ground conductivity
someday and make sure I know what I'm talking about.

Anyway, I'm fairly certain that the function is basically an INVERSE
one, and NOT an inverse-squared function, and the FCC charts show an
equation with 4/3 constant for the earth's diameter because ground-
waves are  "pulled" downward by imperfect conductivity. That means
the field intensity at some distant point is actually higher than
one would expect, because of the 4/3 constant.



>Watts per square meter seems more intuitive to me, but that's not what
>the FCC calls for.

That part is right, and that's why a station has to quadruple power to
double coverage.


>--
>Mesa Mike, N6KUY, WDX6O
>Los Alamos, New Mexico (DM65uv)

Perfesser Chuck
Quiz tomorrow at 0800!


   Charles A Taylor, WD4INP
  Greenville, North Carolina 


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