Suitsat 2/ARISSsat is a linear transponder done with DSP. Its seems perfectly reasonable to me to do transponder signal filtering and command decoding digitally as it makes things smaller and lighter. You could also make a better transponder by forming filters around the uplink signals so downlink power isn't wasted by repeating noise and downlink power could be allocated equally among users.
Putting ARISSsat on the ISS would be nice but NASA and the Russian space agency haven't agreed to that.
73,
John KD6OZH
----- Original Message ----- From: "Rocky Jones" orbitjet@hotmail.com To: k6hx@arrl.net; "Amsat BB" amsat-bb@amsat.org Sent: Sunday, October 18, 2009 15:32 UTC Subject: [amsat-bb] Re: Why do hamsats? (Or anything else...)
That still doesnt answer the question of why on Suitsat 2 they should fly a digital transponder.
In my view better engineering doctrine would imply that we try and put the digital transponder ON ISS and let it "cook" there for a bit. Robert WB5MZO