Hello AMSATs,
I agree that APRS can have a higher power transmittter, because of its small
amount of time to get the data broadcasted. However the workability with the HT
and whipe antenna is only an advantage for the downlink. For the uplink there
will be no advantage.
Personally I believe that making a satellite easier accessable will also
decrease its functional efficiency. This is especially the case for satellites
with limited user access, like single channel FM satellites. This also includes
APRS. The same issue is valide for a geostationary satellite, with the addition
that a geostationary satellite would be overloaded in short time by more and
more stronger stations as fixed antennas can be used. Only the uplink power
level would be the parameter of "competition". Resulting in a privat chat
satellite for only few (high power) users.
Satellites for emergency communication sounds very interresting, and personally
I believe it can give a great advantage when doing it well. The question is
only what will work well in an emergency situation. It will depend on the needs
and the availability of equipment in the effected area. I believe that digital
communication will be of limited use as you need also a computer, modem,
keyboard, screen, software etc besides your radio. Only one thing missing and
you will not be "heared". I don't say it is impossible, but to make the
system work the ground stations need to be made more easier somehow. Maybe HT
APRS in combination with voice to text conversion (and opposite) would be an
idea ?
Besides the technical difficulty there is also the (human) organising factor. I
heared some ideas about an easy to access geostationary satellite with high
power downlink. That would be great, but without any communication control it
would be like the FM LEOs where everyone talks at the same time and nobody is
able to get there message through.
It might be solved with a central control centre on a safe place (maybe by
the Amateur Radio Emergency Service ?) that has control over the satellite
radio and uses it as a remote radio "ear" in space. In this way it is also
possible to use one frequency simplex system.
Just some ideas,
73 de PE1RAH,
William Leijenaar
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