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

each other?

Their footprints have to overlap. The footprint of ISS goes out what, maybe 2000 mi? But most people cannot make good contacts until it is say above about 20 degrees, then it is 6 dB closer at about 1000 mi. Although PSAT has a similar footprint and lets say that its usable range is about 1000mi also. Then they could be 2000 to 4000 miles a part and still see each other right on their horizons.

But that is a long haul for a 5W link. AND, No other ham radio users should be in the footprint of the satellite that wants to hear the other satellite or it will hear so much QRM as to not be able to hear the other one. So if I wanted to do it by distance, I might suggest a round number of 1000 miles maybe.

But it is what else is in that footprint (QRM) that will define the chances of a link.

Bob

On Nov 8, 2018, at 4:25 PM, Robert Bruninga bruninga@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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