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RE: Echo Antenna Polarity



Art,

Back in the Nov/Dec 2002 AMSAT Journal I wrote: "AO-E has a UHF Turnstile
Antenna that is fed by a strip line hybrid antenna phasing network that
provides the appropriate quadrature phase and amplitude to each of four
output antenna ports to produce true circular polarization over a wide range
of squint angles." For the full article see
http://www.amsat.org/amsat/sats/echo/article-02-11.html. 

The turnstile antenna and the hybrid combiner have been redesigned since
then.  It would be interesting to see if this is still true with some tests
after the satellite stabilizes a bit.

Rick
W2GPS
AMSAT LM 2232

-----Original Message-----
From: owner-AMSAT-BB@AMSAT.Org [mailto:owner-AMSAT-BB@AMSAT.Org] On Behalf
Of KC6UQH
Sent: Monday, July 05, 2004 1:10 AM
To: Rick Hambly (W2GPS); 'Bill Ress'
Cc: amsat-bb@AMSAT.Org
Subject: Re: [amsat-bb] Echo Antenna Polarity

Rick,
In the past with LEO's, the antenna pointing angle could sometimes  require
both polarity's. This could happen every orbit or may remain stable for
months dependent on the pointing angle of the antennas on the spacecraft.
 As Echo has both polarities for isolation, am I correct in assuming that
both polarities are necessary, will change with pointing angle, and linear
antennas will not work if both transmitters are operating at the same time?

Art, KC6UQH
----- Original Message -----
From: "Rick Hambly (W2GPS)" <w2gps@cnssys.com>
To: "'Bill Ress'" <diskdrives@ieee.org>
Cc: <amsat-bb@AMSAT.Org>
Sent: Sunday, July 04, 2004 2:32 PM
Subject: RE: [amsat-bb] Echo Antenna Polarity


> Bill,
>
>-------------CUT-------------


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