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[TowerTalk] A Question of GAIN

To: <towertalk@contesting.com>
Subject: [TowerTalk] A Question of GAIN
From: w8ji.tom@MCIONE.com (w8ji.tom)
Date: Wed, 21 Oct 1998 08:48:05 -0400
Hi Guy,

> I am not as ready as Tom to dismiss the rather broad vertical nulls in
> 20-10m yagi patterns at 60+ feet as a large factor in stack behaviour
> during fades. 

Tom me? I didn't mean to imply null filling or movement is not important. I
said (a long time ago) null filling was the advantage of a stack, not gain
improvement.

My point is improved directivity and focusing in the direction of the
signal reduces QSB, not spatial diversity in a fixed phase non-voting
ionospheric circuit. What we are really doing is creating an antenna with a
better pattern, no matter how we care to look at it. That's why it has no
special name.

> I hear two kinds of stories. One where signals are coming in at a
> certain angle, often rather low, and the other where multiple paths
> are active with different time delay, different incoming angles,
> different incoming directions, and different polarizations. 
> As to using the common kinds of BC antennas as a reverse engineering
> inference for what does what in fading... 

I actually stole my data from engineering textbooks that blame fading and
selective fading on multipath in ionospheric paths (like page 33-24 of
Jasik's Ant Eng Handbook, the NAB Handbook in various sections, and so on.
   
73 Tom

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