Jim,
I looked at your presentation and "take off angle" is not mentioned, but
angle is. Granted the gain of a ground mounted vertical with radials
has more gain as the ground becomes better, but I see the angle of
maximum gain getting lower, also.
Tom W0IVJ
On 12/12/2016 8:34 PM, Jim Brown wrote:
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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