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[aprssig] Get ready to receive RAFT and ANDE telemetry!

Robert Bruninga bruninga at usna.edu
Tue Dec 19 19:07:50 UTC 2006


> We are in need of stations around the world to receive 
> this telemetry and gate it to the APRS-IS...
> 
> An easier option: If you have a TM-D700 radio,... set
> [it] to work as a SatGate to help capture these packets.
> [by digipeating over to the national network...]

Although that is a very clever approach, unfortunately, there
are 3 reasons why we do not recommend that except in extremely
remote continents where there is no other way to get the
packets.  

1) The danger of someone missconfiguring their mobile and then
digipeating BACK on 145.825, though small, is bad enough to
reduce the satellite effectiveness by 50% for each mobile that
forgets to properly set their TX frequency.  These stations then
would be jamming the uplink 50% of the time after each packet
heard.  This risk, though small, is not the kind of risk we like
to take in space stuff where such a problem can block an entire
continent.

2) We do not want packets from 145.825 digipeated over to
national APRS networks, because once there, the packets cannot
be determined to be from the Satellites and do not show up on
the PCSAT web pages on FINDU.  This causes frustration and
confusion and takes time of key players to constantly
troubleshoot and comment on.

3) Since anyone that can receive APRS on 144.39 or whatever
national frequency can receive the satelltie just as easily
themselves, there is little advantage to this process.

Now #2 might not be as big a problem as I fear, because
presumably if a -real- satgate gets the packet first, then that
copy may be the one that FINDU see's and then it will ignore all
others [which are delayed by the digipeat (but unmarked as being
via the satellite)].  But it seems not worth the risk.

But thanks for your enthusiasm!  I suggest a parked vehicle with
a D700 would be a great candidate for an RS-232 cable from the
driveway through a window to a PC running as an Igate would also
work when parked at home if one has a clear horizon.  The mobile
antenna will possibly do better than the base station because it
has a shorter less lossy coax run.

De WB4APR, Bob


> You do not need an Internet connection at all for this setup.
> See details here:
> 
> http://aj3u.com/aprs/aj3u-10.php
> 
> Here is the operations website for ANDE and RAFT:
> 
> http://eng.usna.navy.mil/~bruninga/ande-raft-ops.html
> 
> Access for digipeating is not granted until their primary
mission is
> complete.  Look for an e-mail from Bob (WB4APR) for a go-ahead
to
> start digipeating.
> 
> -- 
> A.J. Farmer, AJ3U
> http://www.aj3u.com
> 
> _______________________________________________
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> aprssig at lists.tapr.org
> https://lists.tapr.org/cgi-bin/mailman/listinfo/aprssig
> 





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