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@comcast.net To: amsat-bb@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 _______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb