Greetings,
Bit of a lurker here, but my day job is at a Satellite Earth station for SES Americom, a satellite owner/operator.
Normally, when a satellite is about to run out of fuel, it is sent into what is called a graveyard orbit, to keep it from drifting and running into other satellites. It is boosted high above the geosynchronous belt where it wont run into anything.
A satellite is usually hard wired for the frequencies in use. Up link in the C band is usually 5.9 to 6.4 Ghz, and there are 24 TWTs, each tuned to a 40 Mhz hunk of spectrum.So, Transponder 1 is the first 40, transponder 2 is the second 40, etc....
At Ku band, it runs from 14 GHZ to 14.5 Ghz. sometimes the transponder width is 40mhz, sometimes it is 54Mhz. again, the individual TWT is tuned for its little slice.
All of this filtering is done pre and post amp by hard filters that can not be changed from the ground.
Without command and control of the satellite, it is for all practical purposes useless.
Chris Hackworth N8PHU
On Thu, Mar 12, 2009 at 12:24 AM, w7lrd@comcast.net wrote:
Hello I believe this subject has been kicked around on this BB before. It did generate some creative thinking. Given all the satellites up there and all the varied uses of them, eventually some of them get compromised for whatever reason. Is there any way any of these old relics can be reprogramed, used or otherwise "adjusted" to suit us? We don't need a real good S/N ratio to make us happy, and we are pretty good at cobbling together whatever we want. We have some very informed and smart people on this BB who know. 73 Bob W7LRD Seattle _______________________________________________ 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