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[aprssig] Taking over a dead APRS station (not an object)

Robert Bruninga bruninga at usna.edu
Mon Oct 1 16:00:25 UTC 2012


> regarding having some other station take over beaconing
> for a dead or incommunicado station.

Station A is an old station who's GPS died... (or anything else on the
APRS display)

Station B is an active station that wants to update the position for
Station A so that the tactical APRS picture remains current.

> Did you mean that station A would become object A transmitted
> by station B, or would station B actually be forging station
> A position and status reports (rather than sending object reports
> about A) along with sending its own station B position reports?

Station B simply sends an OBJECT with the new position and with the object
name that matches exactly the old Station A's callsign.  To every other
station on the air, the new OBJECT position for that same-named-thing will
replace the previous last position for the same-named-station A.

That is what many clients ignored when they treat STATIONS and OBJECTS
differently.  In the original APRS, all positions go onto the station list
simply by NAME, not separate STATION and OBJECT lists.  This is why they
become the same if they have the same name and an object can overwrite a
station or a station can overwrite an object.

The "Object" format in APRS was never supposed to be treated differently
than any other position format.  It is just another way to transmit a
"thing" "name" that is more than the 6 character callsign of the TNC
hardware.  Again, the UNIQUENESS of a Name in APRS was the single
identifying element of anything on the APRS tactical display.  It did not
matter what position format was in the original packet (though OBECT ones
were flagged so we could retain who sent them (by callsign) and whether
they are OURS or someone elses.  Remembering that anytime anything of the
same name comes in from anyone else, it immediately cancels our ownership)
Thought of course, we will not overwrite our OWN STATION call.  We always
remain in charge of that..

Notice that if station A resumes transmitting, then station B will see
this new same-named-name and it will overwrite station B's own object of
the same name which will result in station B no longer having an object of
the same name top transmit, so in effect, Station A takes back over his
position.

> I just want to make I'm implementing this properly.

This is exciting news as you fine-tune your YAAP client for APRS.  Let us
know when everyone can start playing with your next BETA version.

Bob, WB4aPR



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