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Re: [Amps] MOSFET amp filtering - was: auto-tune

To: jim@audiosystemsgroup.com, Amps Amps <amps@contesting.com>
Subject: Re: [Amps] MOSFET amp filtering - was: auto-tune
From: Tom Thompson <w0ivj@tomthompson.com>
Date: Mon, 12 Dec 2016 23:23:29 -0700
List-post: <amps@contesting.com">mailto:amps@contesting.com>
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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