[amsat-bb] Re: ARISS Antenna Specifics

[Clare Fowler]

Thanks for the info Frank.

While the spiral dual L/S band ant may nominially be Left Hand Circular
it must be highly eliptical otherwise I would not be getting into it at all
with 10 watts into my Right Hand Helix antenna array. I have Right Hand
and Left Hand helix antennas for 70 cm and on AO-51 when I switch
to the wrong polarity an over S9 signal drops by more than 20 db into the
noise.

So whatever the polarity it is possible to get into ISS on L band
with Right Hand uplink although Left Hand should be better.

Clare VE3NPC

----- Original Message ----- 
From: "Frank H. Bauer" <ka3hdo at comcast.net>
To: <amsat-bb at amsat.org>
Sent: Tuesday, December 30, 2008 12:52 PM
Subject: [amsat-bb] ARISS Antenna Specifics


> All,
>
> The ARISS L-band/S-band antenna systems are Left Hand Circularly
> Polarized.
> There are some good details of the antenna systems in this paper:
>
> http://www.amsat.org/amsat/ariss/Papers/Phase%202%20AGM03Final.pdf
>
> And this presentation:
>
> http://www.amsat.org/amsat/ariss/Presentations/AMSAT%20Symposiums/AMSAT03.pd
> f
>
> Chart 25 of the above presentation shows the antenna locations looking
> down
> the axis of the Service Module.  In this picture, the ISS velocity vector
> is
> either in or out of the page and Earth is towards the bottom of the page.
> This assumes they are in the normal Earth pointing mode (which is not
> always
> a given).
>
> We have some good on-orbit views of the antennas in this set of charts
> too.
> Enjoy!
>
> I hope this helps.  And thanks for all the interest in ARISS.
>
> 73,  Frank, KA3HDO
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