Tom,
"Take-off angle" is a highly flawed concept for trying to understand how
antennas work. Take a look at the links I posted. You won't see the
words "take off angle" anywhere in the discussion. Rather, I've modeled
the vertical and horizontal field strength performance as these soil and
height parameters are changed and plotted the results on the same axes.
When you do that, you learn what really happens.
73, Jim K9YC
On Mon,12/12/2016 7:03 PM, Tom Thompson wrote:
Jim,
/Lousy soil does NOT vary the vertical angle, it simply attenuates the
signal. In the near field, it burns transmitter power by warming the
worms. In the far field, it degrades ground wave and weakens the first
reflection that creates the vertical pattern./
Lousy ground does raise the take off angle of the maximum point on the
lobe of a vertical. EZNEC shows the maximum point on the take off
lobe going from 18 degrees with very good ground to 26 degrees for
rocky mountain ground.
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