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[aprssig] Re:All APRS Digipeaters In The World (Almost!) MappedOn UIview

Robert Bruninga bruninga at usna.edu
Fri Mar 2 21:27:00 UTC 2007


> > The problem is that there is no Multi Task symbol for the 
> > station that does all 3 things Gateway / Node / Digi etc 
> > Maybe a Multi Task symbol could be produced :-)

Igates send out an Igate status packet.  Most clients including
Uiview, APRSdos and others use this to draw a special color
circile around those stations so you can tell the Igates no
matter what symbol they are using.  

TO resolve WX stations that have a high PHG range and also serve
as digipeaters, APRSdos had color attributes for all symbols..
Any symbol that was a DIGI was painted GREEN, and a WX station
was painted blue.  SO a GREEN WX symbol is a combined DIGI at a
WX station.  Or a DIGI symbol surrounded by a BLUE circle was a
DIGI that happened to send out a WX packet.  Problem is, many
APRS clones left out symbol COLOR attributes completely.

>> This is one place where a standalone KPC3+  or 
>> UIdigi-equipped TNC2 has a real advantage over most 
>> programs on a PC,  since you can set three 
>> different beacon texts, each with it's own repetition 
>> rate, path and symbol.into these devices.

APRS discourages oscillating POSIT packets such as that.  All of
the LTexts have always been receommended t be the same.  The
reason is that many clients are set up to LOG all "new" or
"changed" posits, but to not log every copy of an unchanging
posit.  This GREATLY reduces log HISTORY files.  But if a TNC is
beaconing two different position packets (even if it is only
becasuse the TEXT or symbol changes,), these are still changes
and result in exhorbitantly long LOG files due to these
oscillating posits.

Therefore, having oscillating position rpeorts from the same
station-SSID are discouraged.

>> If a station at a single location sends several different 
>> symbols alternately, they will wind up directly 
>> on top of each other.  Only the most recently sent 
>> one will be visible.

Which is another reason why it is discouraged.

I recommend that CLIENT software that wants to resolve multi-use
symbols, should use the originally intended color atributes.  Or
at least draw a different color circle around the symbol if
multiple meanings are intended.  Such as the WHITE (or green)
circle that both APRSdos and Uiview use around any station
symbol that sends out an Igate status packet.  I wish Uiview had
used WHITE, so that it could use a GREEN circle around any
symbol that digipeats.

This does not need an APRS protocol change, but a local
client-display fix to resolve..

Bob





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