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Re: Question to Sat ops about ISS

It seems that by far your best chance to make a voice contact with ISS is during Field Day.  Believe it or not, I have made ISS voice contacts two times out of two attempts during Field Day.  The first time was during Field Day 2001.  It was the first time I ever listened for ISS.  I got the frequencies, and heard the astronaut calling "CQ Field Day" when ISS went overhead.  I got through on the second or third call.

I didn't get around to listening for ISS during Field Day 2002, but I read that they also made a lot of voice contacts then as well.  I tried again for Field Day 2003, and made a voice contact on the first ISS pass that I listened to.  The pass was about half over before he showed up.  I think I got through on the third call.

I was using an "Oscar class" station for both of my Field Day ISS contacts (50W to a 7x7 RHCP yagi).  I think your chance of making a Field Day ISS contact with a mobile-type setup is not very good unless you can catch the ISS when there isn't much population in the footprint.

During Field Day 2001 I talked in person to a guy who had made several ISS voice contacts from his truck while driving home from work.  He was evidently using 50W or less to a vertical whip antenna, and he had the ISS downlink frequency programmed in the scan list of his 2m FM mobile.  So he listened for ISS every day on his way home from work.  The key was that he gets off work at 3 PM Central time, shortly before the astronauts go to sleep.  The astronauts are sleeping during the evening hours in North America, so it's useless to listen then.

ISS voice activity varies greatly from one crew to the next.  It really is hit or miss.  There is no reason to call them.  The best you can do is to continuously monitor the downlink and jump in if you hear them.  It's a shame that the same downlink is used for packet.  That makes it more difficult to continuously monitor for voice activity.

Wayne Estes W9AE
Mundelein, IL, USA
Sent via amsat-bb@amsat.org. Opinions expressed are those of the author.
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