[amsat-bb] Re: Double leo satellites
bruninga at usna.edu
Mon Sep 15 12:25:03 PDT 2008
Here is the link to our new Psat (dual APRS satellite
> -----Original Message-----
> > Should it be possible to launch two Leo
> > satellites...(satellite A) retransmitts
> > what it hears to the other Leo satellite
> > (Satellite B)... I think in that way i
> > could work NA every day?
> That is the intent of the APRS constellation
> of satellites. All operating packet on 145.825.
> We want to get as many of these satellties in
> orbit as we can to not only provide continuity
> of coveratge, but also dual-hop capabilities as
> you suggest.
> APRS can inherently, auomatically, work via
> dual hops, since it uses a generic path which
> does not need to be configured for each
> satellite callsign.
> That is also why the ISS moved to 145.825
> a year or so ago, to be on the same channel,
> with PCSAT-1,PCSAT2,ANDE, RAFT, and others.
> There have been several instances of dual hop
> packets. The longest one recorded was from
> Africa over the Atlantic to Maryland. See:
> Unfortunately, only ISS and PCSAT-1 remain
> in orbit and PCSAT-1 only works under some
> conditions, and ISS only works under others.
> But if you can find them both working at the
> same time, then dual hops are possible.
> You can watch the downlinks from these two
> birds and look for activity and dual hops
> just by looking through the on-line real-time
> downlink logs:
> www.ariss.net for the ISS
> http://pcsat.aprs.org for the others
> You can see that ISS has been off the air
> for 79 days except for a brief period 2
> weeks ago. And PCSAT-1 (W3ADO-1) continues
> to limp along with some lucky packets during
> northern hemisphere mid-day passes.
> Ideally, if we can get 6 to 10 small APRS
> satellites on 145.825, we can provide near
> continuous message/email/status capabiliy
> from anywhere on Earth at any time. That
> is why I encourage all Universities making
> CUBESATS or other small satellites to
> include a 145.825 1200 baud packet link so
> their satellites can be used in this
> constellation after their primary mission is over..
> Our next Satellite from the Naval Academy
> will actually be two-cubesats-at-once.
> Both on 145.825 with APRS transponders.
> Please, if anyone is working with other
> universities, see if they would consider
> this global constellation mission for
> their transponder...
> Bob, Wb4APR
> Sent via AMSAT-BB at amsat.org.
More information about the AMSAT-BB