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From: Rem%IMSSS@sri-unix.UUCP
Newsgroups: net.space
Subject: SATCOM polarization
Message-ID: <13249@sri-arpa.UUCP>
Date: Fri, 7-Sep-84 14:14:00 EDT
Article-I.D.: sri-arpa.13249
Posted: Fri Sep  7 14:14:00 1984
Date-Received: Thu, 13-Sep-84 19:53:11 EDT
Lines: 21

It would seem to me that horizontal polarization is ambiguous, is it
N-S or E-W, while vertical polarization is bad design, because the
Earth is nearly exactly under the satellite (point on equator is exactly
under satellite, while anywhere else on Earth such as North American
ground station is at most 4000 miles deviation from exactly-under at
a distance of 24,000 miles) and electromagnetic signals propagate only
at right angles to their electric field change (and at right angles to
their magnetic field change; the three vectors form an orthogonal set
in 3-space), thus using cosine rule conversion from antenna beam field
and transmission direction you'd get very little signal at Earth.

I suspect by "horizontal" they mean "horizontal at ground station that
is due North of beam point" which would mean east-west, while "vertical"
would mean north-south. This still leaves the question of whether they
are talking about the electric or the magnetic field vector. Can I
assume they are talking about the electric field vector??

Or are they really using some strange kind of circular polarization that
appears horizontal from all points on Earth (except directly under satellite
where it can't be received at all)?
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