Hi All: With respect to the question concerning horizontal versus vertical
polarization and the practical effect in amateur radio communication, just
take a look at how commercial satellites make use of vertical and
horizontally polarized channel allocations to get the most use out of
limited transponder bandwidth resources.
"The Electronics Handbook - Page 1659
Jerry C. Whitaker - 1996 - Preview - More editions
Beam and polarization isolation: Frequency reuse allocates the same bands to
several independent satellite transponder channels. The only way these
signals can be kept separate is to isolate the antenna response for one
reuse channel in the direction or polarization ... Isolations of 27-35 dB
are typical for reuse systems."
(Search terms for this reference: ( "satellite transponder" channel
"polarization isolation" dB )
Keep in mind a satellite dish is a high gain antenna, and the polarization
(horizontal, vertical, circular/elliptical) is closely controlled. The
effect with typical amateur antennas is more noticeable with stacked
antennas and properly isolated transmission lines. For example, my 4
stacked halos on 430~450 MHz are "very horizontal" when each is properly
matched with a balun (which tends to limit vertically polarized line
radiation) and properly stacked. I have difficulty getting into local FM
repeaters with the 430~450MHz stacked halos that are up 50 feet and used on
my 432.322 MHz weak signal cw beacon. Yet, I routinely get weak signal
beacon reports from KU8Y near Chicago for my 432MHz beacon near Pittsburgh.
One other thing to remember is that for each antenna side lobe in an antenna
pattern, the polarization switches. You can use this to an advantage if you
have a horizontal yagi antenna and want to communicate more effectively with
a station (stuck with) using vertical polarization---just use a vertically
polarized side lobe of your horizontal yagi. Usually there will be a
vertical side lobe at some angle off the back of the yagi antenna. It takes
a bit of practice to find the vertical lobe, but it works and the technique
can allow you to pull that 10 watter out of the noise in a VHF contest using
his quarter wave vertical on 144, 222, or 432 MHz horiz ssb/cw mode....
73, Mike wa3tts
On Sun, Jan 29, 2017 at 10:38 AM, Buddy Morgan via VHFcontesting
<vhfcontesting@contesting.com> wrote:
Of course, I am horizontally polarized.
Undoubtedly, that makes a difference ... but how much?
Does anyone have a scholarly (or even semi-scholarly, e.g., QEX, QST)
citation for the amount of attenuation? I've heard anywhere from 3 dB
to 30 dB (and WAGs going even higher). 3 to 30 dB doesn't seem like
much to a lot of hams because they don't understand dB, but that's
2x(ish) to 1000x ... so I'm thinking one of them is wrong ... and
since we all routinely hear signals of the other polarity I'm thinking
it's closer to 3 than 30 ...
Someone has surely done actual research on this. So where is it?
--
Peter Laws | N5UWY | plaws plaws net | Travel by Train!
------------------------------
Message: 2
Date: Sun, 29 Jan 2017 12:30:05 -0600
From: <w5prchuck@gmail.com>
To: Peter Laws <plaws0@gmail.com>, vhf contesting
<vhfcontesting@contesting.com>
Subject: Re: [VHFcontesting] Attenuation from polarity mismatch (Re:
C6AFP SixMeter Beacon
Message-ID: <588e34ae.0dabca0a.89eaf.e377@mx.google.com>
Content-Type: text/plain; charset="utf-8"
The answer is: ?It depends.? In a perfect world, no power would be
transferred. The number I see most often for the real world is 20db.
Chuck W5PR
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