All comments have been very interesting, but I think Steve may have already
nailed this thing with the comment about having MULTIPLE antennas to choose
from. One may hear better ( or transmit ) than the other at any given time
due to variables. It pays to have choices. This may or may not be possible
for some. '73 all. Enjoy the Easter Weekend. - Mike
-----Original Message-----
From: towertalk-bounces@contesting.com
[mailto:towertalk-bounces@contesting.com] On Behalf Of jim Jarvis
Sent: Friday, April 10, 2009 11:08 AM
To: towertalk@contesting.com
Subject: Re: [TowerTalk] polarization change
I wasn't going to comment on this, because wiser heads have
prevailed, on this topic,
for the most part.
HOWEVER, I learned something today that may be worth contributing to
the discussion:
I have always assumed that fading was principally a result of changes
in arrival angle,
due to ionospheric dynamics, and accepted the literature which said
that all signals arrived
horizontally polarized. This morning, I learned that it may be
polarization that is the principal
variable.
At k2ttt's place, getting my taxes done, we were playing with his new
K3, and discussing the
impact of having dual receivers. This past season, on 160m, he had
an inverted vee, horizontally
polarized, and a loop, which was fed to be vertically polarized.
By putting one antenna into each receiver, he was able to observe
that the principal variable
seemed to be polarization. Selecting diversity receive, he had dead
solid signals, when either of
the individual channels was fading to the point of no copy.
Although 160 may be different from higher bands, this anecdote does
seem to run counter to
the prevailing wisdom that the ionosphere tends to make all signals
arrive horizontally polarized.
While this strictly speaking belongs on the topband reflector, one
antenna was hung from a tower,
and the other had to avoid coupling to the tower. So the comment is
peripherally relevant to TT.
N2EA
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