Les,
Don't forget, these issues are all under review as we speak.
The answer is in two parts. First, an L-band ground antenna would be too large to disguise as a TVRO dish. Second, there is fear that over the lifetime of Eagle that L-band could become unavailable, particularly in Europe, if the Galileo system is deployed. Galileo would be a primary service and Ham transmissions would likely interfere with low cost commercial receivers.
I don't wish to debate these points. I'm just telling you the reasoning that went into not choosing L-band. I assure you that every possibility was considered. Lists were created and discussed on each alternative.
Rick W2GPS AMSAT LM2232
-----Original Message----- From: sco@sco-inc.com [mailto:sco@sco-inc.com] Sent: Tuesday, September 19, 2006 11:29 PM To: Rick Hambly (W2GPS) Cc: amsat-bb@amsat.org Subject: Re: [amsat-bb] Re: Why do the amsats get more and more complex?
Maybe someone can explain why Eagle could not use the L Band for its digital uplink instead of S Band? Then you would have a L/C mode and many users already have a L band uplink capability.
Les W4SCO
Eagle will carry a payload that it is hoped will revolutionize Amateur Satellite communications and Ham Radio as a whole. Initially called C-C Rider, I will call it the Advanced Communications Package (ACP) because it no longer uses C-band for both uplink and downlink. This package will be designed to bring satellites and DX to you and to many other Hams who have never been able to use a satellite or operate DX before. This is because the ground station antenna will be small, power levels reasonable, many modes will be supported (from Voice and CW to Video and data communications), the ground station will be affordable and the signal quality will be superior. Much of this is accomplished through the use of digital techniques so it will require all new equipment on the ground.
AMSAT
will design the ground station equipment and publish everything so you can buy it, copy it, sell it, or build it.
The Eagle band plan has been the subject of much discussion, of late.
Eagle
is still in the design phase and the band plan is not finalized, so don't worry just yet. The confusion was the result of the ACP (C-C Rider) team realizing that they had to find another band for the uplink. They chose S-band for some good reasons but that recommendation is under review by the whole Eagle team and is not yet final. There should be a final announcement at the AMSAT Symposium in a few weeks. I encourage everyone to come to the Symposium and meet your AMSAT officials and learn what is really happening in AMSAT.