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RE: CC Rider Questions



Steve,

The Eagle C-C Rider payload is intended to be a combination of four great ideas in
one project. 

1) W3IWI's original "C-C Rider" 5GHz in-band transponder.
2) N4HY's Software Defined Transponder (SDT) concepts.
3) KA9Q's KarnSat digital backbone (~1Mbps).
4) WA4SIR's "IP in Space" concept.

The concept for this came together in a pair of "Dream Payload" meetings held in my
Lab in February and May of 2004. Each of the four parts builds on the previous parts
and should result in a communications mode that simultaneously allows users to
operate voice, data, video, and other modes while minimizing the need to track
Doppler, even if fielded on a low orbit satellite. The user will only need a small
antenna with single band feed, which could allow users in restricted communities to
disguise the antenna as a TVRO. 

The low level protocols, including multi-user uplink access protocols, have not been
designed yet.  We are still working on the design for the RF and the electronically
steered beam antenna for the satellite.  The modulation will probably be BPSK.  The
downlink will probably be on the order of 500Kbps data rate. Uplinks will probably be
about 10Kbps (effective) per channel. A lot depends on the evaluation of link budgets
(thanks to W3GEY/VK4GEY for the link budget tools).

If we reach goal #4, the lower protocol layers will present an Application
Programming Interface (API) at the IP level so any applications that are available
for the Internet should work on the satellite.  That includes things like EchoLink
(voice), FTP, Web page servers, etc.

The AMSAT community will be able to participate in the development and operation of
this new concept in communications as the design will be "open source" under a GNU or
GNU-like license.  This includes both hardware and software.

We do not expect to achieve all our goals in the first transponder implementation but
we will implement the core elements of this vision.  Ultimately we hope to introduce
a whole new concept in open accessible satellite communications that will
revolutionize the Amateur Satellite Experience.

Rick
W2GPS
AMSAT President
 
-----Original Message-----
From: owner-AMSAT-BB@amsat.org [mailto:owner-AMSAT-BB@amsat.org] On Behalf Of Steve
Meuse
Sent: Wednesday, August 03, 2005 7:43 PM
To: amsat-bb@amsat.org
Subject: [amsat-bb] CC Rider Questions

I've been thinking about CC-Rider lately and I think it's going to be a really neat
experiment, but I have a question about the operation of the transponder. I've read
the whitepaper "C-C Rider Revisited" but I didn't see anything that comes out and
specifically talks about whether the transponder will be digital voice or standard
analog. I see some mention of the KarnSat protocol, but I haven't been able to find
any info about that. I realize we're still in the very early design stage, but I'm
curious as to what the designers are thinking for transponder usage. It would be
interesting if we could support both digital and analog transponders simultaneously.

Is there any public information on the KarnSat protocol? I keep thinking about the
possibilities of having a dynamic data network between groundstations while the sat
is in view. This could be a killer app for multicast :)

-Steve
N1JFU
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