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Topband: W1WCR Beverage book

To: <topband@contesting.com>
Subject: Topband: W1WCR Beverage book
From: W8JI@contesting.com (Tom Rauch)
Date: Sun, 14 Jul 2002 12:46:36 -0400
> Why would a Beverage respond to vertically polarized signals anyway?
> With a Beverage over perfect ground and a zero degree arrival angle,
> there would theoretically be no induced signal in the antenna.

The Beverage actually responds to the voltage gradient caused by 
attenuation along the ground, which is just another way of saying the 
wave tilt.

That tilt or voltage drop along the lossy earth is the same for 
groundwave signals as it is skywave signals.

It doesn't matter how we look at it, the result is any vertically 
polarized signal will excite the entire antenna, including the short 
vertical ends or the long horizontal middle. If vertically polarized 
signals didn't excite the horizontal section, the antenna would not 
be useful at a few feet height!

The reason you don't see the low or zero elevation angle sensitivity 
in a model is because most programs we use calculate the field at a 
very very large distance and that prevents the plot from having any 
response along the earth, unless you put in perfect ground. (But if  
you do that, the Beverage will quit working in the model because 
attenuation along the ground will be zero, so there will be no 
"tilt".)73, Tom W8JI
W8JI@contesting.com 


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