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Re: Polarization of HAMSAT downlink



Hi William, PE1RAH

           That information from ISRO is very interesting, as the 
last QSOs that I made on (VO-52) HAMSAT was using RHCP
polarization on downlink.  I did notice that I seemed to be able
to work it better each time when HAMSAT passed over me,
and was descending away from me.  Perhaps I should have
switched to LHCP early in the passes to check.  For some 
odd reason, I thought RHCP was just "standard."

          However, both of my satellite antenna systems are
switchable on CP polarization, except for the Mode-L,
which uses two linear 24-element Yagis phased together.
I am very interested in what you find out about the uplink. 

73,
Charlie, N5TD
  

          ----- Original Message ----- 
From: "William Leijenaar" <pe1rah@yahoo.com>
To: <amsat-bb@AMSAT.Org>
Sent: Thursday, June 30, 2005 12:28 PM
Subject: [amsat-bb] Polarization of HAMSAT downlink


> Hi AMSATs,
> 
> I was away for a few days and arrived back home
> yesterday. When I checked my email I see an answer
> from ISRO on my question to confirm the polarization.
> 
> I think I remembered that it was said to be RHCP, but
> this is wrong... 
> 
> ISRO confirmed in the email to me that the downlink of
> HAMSAT is LHCP. They advise to use linear antennas to
> avoid fluctiations in downlink signal level due to
> polarization changes. The downlink is strong enough to
> overcome the 3dB losses you have with a linear antenna
> to an circular antenna.
> 
> About the uplink they didn't mention. I request them
> also to confirm about the downlink polarization.
> When I get the answer I will post it...
> 
> 73 
> William
> PE1RAH
> ---
> ----
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