The goal is availability over 3/4 of the orbit for both SSB users and users of newer modes. 2 satellites in the right orbits could provide availability close to 3/4 of the time. This is good for all amateurs as they can use satellites when it is convenient for them rather than scheduling their activities around the satellite.
NGOs have stated to various ARRL committee members that they want digital communication at as high a speed as possible 24/7 -- this has been known for years and is why the ARRL is encouraging use of HF digital links (even though they are slow) for emergency traffic. The fact that technology has advanced to the point that amateur satellites can do this is a good as it can give us another application for the satellite and another group of hams that can become interested and more potential donors.
The nice thing about digital commnication and digital signal processing is that we can use it to allow voice communication for hams with small stations and then re-use the same hardware for high-speed data for larger earth stations.
73,
John KD6OZH
----- Original Message ----- From: "George Henry" ka3hsw@earthlink.net To: "amsat bb" amsat-bb@amsat.org Sent: Sunday, September 24, 2006 03:15 UTC Subject: [amsat-bb] Re: Eagle and emergency traffic (was Re:Galileointerference on L band)
----- Original Message ----- From: "John B. Stephensen" kd6ozh@comcast.net To: "George Henry" ka3hsw@earthlink.net; "amsat bb" amsat-bb@amsat.org Sent: Saturday, September 23, 2006 5:08 PM Subject: Re: [amsat-bb] Eagle and emergency traffic (was Re: Galileointerference on L band)
Why would it be available for only short periods? Eagle is a HEO.
73,
John KD6OZH
I said RELATIVELY short periods... what is the maximum time that the proposed data transponder will be available to a given ground station, with favorable squint angles, on any given orbit? What is the TOTAL, cumulative access time per day? From the perspective of an emergency manager or disaster team captain, it is certain to seem small when 24/7 service is available from other sources, particularly sources that they have already invested in. And since the design team is looking into their crystal ball at what the state of things will be 5 years down the road at launch, surely they have seen that the entire internet access landscape is sure to have undergone a sea change by then? (Bill Gates sure seems certain of that...)
I repeat: if the design team has anything from the NGOs to bolster the claim that they (NGOs) "need it for emergency data communications", then let's see it.
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