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[aprssig] Police-9/10 station

Robert Bruninga bruninga at usna.edu
Thu Jun 19 18:13:00 UTC 2008


> Correct me if I am wrong, but I would have 
> expected an "object" type of  message to look like:
> 
>    WB4APR>[routing info]:;POLICE-9 *[time][position]

In the original APRS concept, there is no real distinction
between "stations", "objects" or anything you want to call
"something placed on the map" in APRS.  Lets call them "things".

Now, "things" in APRS can be transmitted in many formats.  The
most commmon were often called "stations" because they simply
used the CALLSIGN of their TNC to be the name of their "thing".
But since CALLSIGNS can only have 6 letters, we added a special
format that we called "objects" that allow "things" with up to 9
letters to be transmitted.

In the original APRS, these "things" no matter what their
format, or how they are received, are all treated equally.  They
are all "things" to display on the map and stored the same way.
It was a big error in the writing of the APRS spec that it made
a distinction between stations and objects instead of realizing
that they are 100% interchangeable (except for the 6 or 9 letter
naming issue).  And this is why many programs cannot display an
OBJECT with a weather station in it, or a moving DF object, or
an object mobving with DF info, or any other combination of the
two.

In this case, to transmit a "thing" in the Mic-E format used by
the kenwoods, one has to place the "thing's" name into the
callsign field, and then add one's ownership info in the text
part of the packet.  People with mobile ARPS radios are usually
the first to see an incident or thing that needs reporting to
everyone else.

That is why mobile operators need to be familiar with how to
send such "things" from their radio while mobile.

APRS, its all about the INFO you transmit.

Hope that helps.
Bob, WB4APR







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