[OZAPRS] VK5EX-4

[Robert Bruninga]

>>> "Tony Hunt" <wavetel at bigpond.com> 5/9/2005 5:23:42 AM 
>... it is a STATUS frame ..
> Many APRS clients dump this info if there is no 
>position information for the station to match it 
>up with..Some clients store it until there is a posit ..

APRS is a communications system, not a vehcile
tracking system.   Every station has two types of 
packets associated with it.   A position packet and 
a Status packet.  It is amazing that some software
ignores stations until they have a position.  This
shows no understanding of what APRS is all about.

If APRSdos hears any packet from any station no
matter what kind it is, it will capture that station and
will even create a "vicinity" plot in the vicinity of the
first digipeater heard in the path.  This way, you can
immediately tell about what area someone is in.

The vicinity plot is not an ICON, but an ambiguity
circle in the vicinity of a digi with a big question mark
so there is no confusion that this is a real position
or not.    But for messaging purposes, it is essential
to know where someone is approximately even
if you have not yet received a position from them.

Its a real violation of the integrity of APRS to not
capture stations into the system until they have
a valid posit.  When I travel, all the time, with my
D7 HT, I often start messaging with the D7 without
any valid posit.   Some software even goes so far
as ignoring message packets at the iGates unless
a valid position is transmtted.  This just really
screws up the intent of APRS..

Of course on HF, there are no digis and so
vicnity plotting doesnt give you any new info...

Bob

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