[amsat-bb] APRS satellite dual hop

[E.Mike McCardel]

Bob,

How close would the two satellites need to be with each other to hear each other?

EMike McCardel, AA8EM
Senior Editor AMSAT News Service
Past AMSAT-NA VP Educational Relations


> On Nov 8, 2018, at 4:25 PM, Robert Bruninga <bruninga at usna.edu> wrote:
> 
> 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
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