[amsat-bb] Re: Circular polarization

i8cvs domenico.i8cvs at tin.it
Sun May 13 17:03:32 PDT 2012

---- Original Message -----
From: "David 4X1DG" <4x1dg at iarc.org>
To: <amsat-bb at amsat.org>
Sent: Sunday, May 13, 2012 6:30 PM
Subject: [amsat-bb] Circular polarization
> >
> >Is a UHF circular polarization antenna needed for the current operational
> >satellites?
> >I am planning some work on my antenna system and wonder if the CP
> >is needed, or actually, deteriorate the signal by 3dB if the satellites
> >are
> > using linear antennae??
> >

> The best option would probably be a rotatable antenna, a sat will never be
> fully horizontal vertical or circular, sometimes it even makes a
> difference when you flip 180 degrees.
> --
>73 Andre PE1RDW

Hi Andre, PE1RDW

I agree.

A rotatable boom by 90 degrees is a very good option for a linear antenna
because in a certain moment a sat can send to you a polarization between
linear or through circular i.e. an elliptical polarization that can be
matched by turning the antenna over the boom.

BTW since the polarization changes very rapidly the speed of rotation of the
boom must be very fast, let say maximum 10 seconds or less to rotate from
0° to 90°

73" de

i8CVS Domenico

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