[amsat-bb] APRS satellite dual hop

[Robert Bruninga]

My bad.  I misread it as a dual hop.  The dual *s put in by some TNC's
confused me.

Here is how a 2 hop packet transmitted as ARISS,ARISS would look on the
downlink in a normal TNC:

PSAT,ARISS,RS0ISS* going one way or   (least likely)
RS0ISS,PSAT,ARISS* going the other      (more possible)

And remember, no one will find these on the ARISS or PSAT downlink pages
because most likely only the first hop will be captured and the second hop
will be rejected as a dupe.

That is why everyone should always watch the downlink live if they want to
capture one of those rare 2-hop APRS packets.

HERE IS HOW TO DO IT:

Challenges: Since PSAT has only a 0.2W transmitter, the ISS is simply
never going to hear it.  But the chance of PSAT hearing the ISS is 20
times better.  SO the best chance of success is via ISS first then PSAT.
But if they both hear the uplink packet, then PSAT will be transmitting at
the same time ISS is and so a dual hop is blocked.

So here is the best scenario for dual hop success:

1) Transmit stations via ARISS,ARISS on one continent hitting only ISS and
NOT hitting PSAT at same time
2) PSAT in footprint of ISS but also over mostly ocean so it might hear
ISS without lots of user QRM
4) Receiving station on a distant continent looking out over water towards
PSAT.

Then chances could be good.  Notice, the transmitting stations can be any
users as long as they are using the ARISS,ARISS path.  So the only person
that has to do any planning is simply coastal receiving stations.

With both ISS and PSAT now operational, this would be a good time for all
users to be using the transmit dual hop path of ARISS,ARISS to maximize
someone else on some other continent receiving them!

-----Original Message-----

> Fm N0AN-10 To CQ Via PSAT*,ARISS* <UI pid=F0 Len=43 >[14:50:57]
> =4206.15N/09402.30W`73 v. ISS de Hasan N0AN
>
> Fm WD9EWK To APK002 Via PSAT*,ARISS* <UI pid=F0 Len=21 >[14:51:11]
> :N0AN-10  :hi dm43{N