[Date Prev][Date Next][Thread Prev][Thread Next] - [Date Index][Thread Index][Author Index]

Re: BOB WHAT IS A TRIPLE HOP? ISS/PC SAT 10/30/2002



Arthur asked about a triple hop:

When both ISS and PCsat are within view of each other and with users in
view of each, then it only takes a double hop from one spacecraft to the
other to validate sateellite-to-satellite communications for this
experiment.

But many times the lower ISS is completely out over the ocean with not a
single HAM operator in view.  THus the ISS channel is perfeclty clear,
except for PCsat which at 800 km up, can still see it.  So then it is very
easy to get a packet through PCsat and then through ISS...

But like a tree in the woods, no one will know it happened unless then you
digipeat the packet from ISS back through PCsat a second time.  There the
packet has to contend with all the users on the PCsat uplink too.  So the
probabilities are small...  but remember, ISS has NO QRM at that point.

So on the three passes today, with ISS and PCsat in view of ech other, I
was trying to go via the path of UNPROTO CQ VIA W3ADO-1,RS0ISS,W3ADO-1.
Many others were still trying the path of via W3ADO-1,RS0ISS    but since
ISS was over the horizon and in the middle of the Atlantic, then these
packets even if successful would not have been heard by anyone... thus I
asked people to change at that point to 3 HOP paths or to QRT so that  any
successful 3 hoppers would have less QRM...

So far, no reports have come in of any successful 3 hop packets.

de WB4APR@amsat.org, Bob

PCsat WEB  page     http://www.ew.usna.edu/~bruninga/pcsat.html
ISS-APRS FAQ:       http://www.ew.usna.edu/~bruninga/iss-faq.html
CUBESAT Designs     http://www.ew.usna.edu/~bruninga/cubesat.html
APRS LIVE pages     http://www.ew.usna.edu/~bruninga/aprs.html
APRS SATELLITES     http://www.ew.usna.edu/~bruninga/astars.html
MIM/Mic-E/Mic-Lite  http://www.toad.net/~wclement/bruninga/mic-lite.html


----
Via the sarex mailing list at AMSAT.ORG courtesy of AMSAT-NA.
To unsubscribe, send "unsubscribe sarex" to Majordomo@amsat.org



AMSAT Top AMSAT Home