[TowerTalk] Re: Take off angles

[Jim Lux]

----- Original Message -----
From: <zl1aih at ihug.co.nz>
To: <towertalk at contesting.com>
Sent: Monday, October 18, 2004 12:51 AM
Subject: [TowerTalk] Re: Take off angles


>
> >The problem with the experiment is that which mode is open, or how
> MANY modes are open and which one(s) being used, may not be
> determinable or selectable unless both ends have an antenna with a
> very narrow vertical aperture.
> Guy.<
>
> I wonder if Guy's observation begs the question, if both ends have
antennas
> with different vertical apertures (or horizontal patterns) which is more
often
> the case, then different take off angles versus arrival angles might go
some
> way to explaining the apparent paradox of 'one-way-skip'.

It's also well known that the ionosphere isn't a symmetric channel.  The
index of refraction is polarization and direction dependent.  (For instance,
think about Faraday rotation, a bane of linear pol links at VHF through the
ionosphere, which requires an anisotropic medium)