Re: [amsat-bb] Phase 4 satellite(s)?

[tlang@xxxxxxxxxxxxxxxxxxxx (Tony Langdon)]

Hello John!

24 Dec 00 09:23, you wrote to All:

 JO> In looking at all the mail passing through this reflector recently it
 JO> is obvious that the only type of satellite project for the future that
 JO> will satisfy everyone is one that doesn't cost much, allows world-wide
 JO> communication and is usable from a portable station with a fixed
 JO> antenna.

Someone's listening to the users, it seems. :)

 JO> This isn't technically feasible with one satellite. However, it is
 JO> feasible with a network of satellites that are interconnected. The
 JO> number of satellites must be limited in order to fit AMSAT's budget. I
 JO> read through some old AMSAT-NA Proceedings and see one possible
 JO> solution.
 JO>

True, multiple birds are feasible.

 JO> To provide long distance communication, these satellites must be
 JO> linked even if they are not visible to each other. 20 ground stations,
 JO> interconnected via the Internet, can provide this linking. Initially,
 JO> coverage will not be continuous but intercontinental communication is
 JO> provided in long enough intervals to permit a normal QSO.  Each
 JO> satellite must have the capacity to support at least 10 simultaneous
 JO> conversations so we don't have the problems associated with existing
 JO> single-channel LEOs. The capacity and coverage can be improved over
 JO> time as there are more users of the satellite network.

Interesting idea.  The Internet is certainly a potentially useful medium, but I
do have some reservations.  For thos operators like myself, who are used to
timing things, the Internet is likely to introduce some serious delays.  Still,
this is what ham radio is all about, making different systems work, and
tweaking.  Using the Internet may be considered "cheating" by the purists, but
OTOH, it's yet anohter marriage of RADIO and other available technology.

 JO> while relaying. User uplinks and downlinks could support both analog
 JO> FM and digital modes. N8FGV indicates that digital voice requires
 JO> 2.4-13 KBPS or 5-25 kHz of spectrum per conversation so the Intenet
 JO> bandwidth is not that expensive and we have enough spectrum available
 JO> in the V, U, L and S bands for many of these satellites.

Well, V is a bit tight, I wouldn't put any more than one channel in the V band,
but U L and S certainly have space for a few channels each.


 JO> Does this sound like a useful project?

The idea sounds like it has merit.  perhaps someone with more knowledge could
pass comment as to the feasibility.

Tony, VK3JED

.. If it works, rip it apart and find out why!!!
--
|Fidonet:  Tony Langdon 3:633/284.18
|Internet: tlang@freeway.apana.org.au
|
| Standard disclaimer: The views of this user are strictly his own.


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