[amsat-bb] Re: BBsat Call for ideas

cathrynham cathrynm at junglevision.com
Wed Nov 26 09:52:19 PST 2008

How about this.

1.  On the satellite there's a 9600 FSK regenerating repeater.
If it hears a bit, it sends a bit without any other smarts.
2m up, 440 down. 

2.  Also there's a clock.  It puts out a tick 8 times
per second.

3.  For the ground stations, we design a simple
TDMA system.  Each user gets a time slot for
transmitting into the satellite. Let me see, 9600
baud is 960 characters a second, so we break
that into 8 blocks of 100  character or so every second and
for up to 16 users for a 2 second time block. Enough
bytes to do a small ax25 packet, or maybe we just
stew up something new. Callsign + checksum + data.

3.  Then we just make it a big chat room in the sky. The
thing flies over, you type on your computer and then
your software uses an unused time slot for
sending the data.  Everyone can read your message,
and can chat back to you.

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