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Re: [VHFcontesting] Attenuation from polarity mismatch (Re: C6AFP SixMet

To: Peter Laws <plaws0@gmail.com>, vhf contesting <vhfcontesting@contesting.com>
Subject: Re: [VHFcontesting] Attenuation from polarity mismatch (Re: C6AFP SixMeter Beacon
From: N1BUG <paul@n1bug.com>
Date: Sun, 29 Jan 2017 13:39:59 -0500
List-post: <vhfcontesting@contesting.com">mailto:vhfcontesting@contesting.com>
In the real world over a free space path with typical amateur antennas I believe it is about 20 dB, perhaps (sometimes) more. That is the figure I used in writing software to calculate polarization mismatch signal loss on the EME path years ago.

Usually there is a great loss on terrestrial paths but I have seen some exceptions where reflections from terrain or large objects was involved. In extreme cases, signals can actually be better with cross polarization! The owner of a 2 meter repeater (before my enlightenment) 70 miles away thought I was crazy when I told him I could hit it with horizontal polarization but not vertical. That situation was consistent. The antennas (yagis) shared a common boom so they were not in different locations.

73,
Paul N1BUG



On 01/29/2017 01:30 PM, w5prchuck@gmail.com wrote:
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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