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[Towertalk] Re: Comparison!!

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Subject: [Towertalk] Re: Comparison!!
From: (gary b)
Date: Mon, 15 Jul 2002 19:31:24 -0400
On July 14th Sherman boasted.....

> My plans are to put one at the top of my 110 foot rotation tower (see
> .  With the property at over 2000 feet above sea
> level on top of this mountain, it should work gang busters

Just a note to consider...  gain is increased by reducing radiation in
UNwanted directions and radiating some or all of the energy in desired
direction(s).  As we discovered years ago using the StationMaster-series of
antennas, the antennas performed remarkedly when placed at a high-profile
site...  ~ 600' AAT.  Our usable coverage area expanded considerably.
Unfortunately, mobiles within 10 miles of the xmtr site couldn't access the
repeater!  The high gain of the antenna created a null (or loss of signal)
in the area immediately (below)surrounding the site.  The antenna was simply
"overshooting" nearby stations.  The signal was maximized for the horizon.
The textbook solution to this problem was to mount TWO antennas... one
upside down just below the 'top' antenna.  This takes advantage of the
radiation angle of the main lobe.

I mention this as "food for thought".  Perhaps you already thought of this
and have planned accordingly.  Perhaps it doesn't apply.  BTW... we also
used split antennas to compensate for this and other problems, such as
'desense':  xmit antenna low and rx antenna high.


gary b

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