[amsat-bb] Re: Eagle and emergency traffic (was Re:Galileointerference on L band)

John B. Stephensen kd6ozh at comcast.net
Sun Sep 24 07:36:07 PDT 2006

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 



----- Original Message ----- 
From: "George Henry" <ka3hsw at earthlink.net>
To: "amsat bb" <amsat-bb at 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 at comcast.net>
> To: "George Henry" <ka3hsw at earthlink.net>; "amsat bb" <amsat-bb at 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
> 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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