[aprssig] APRS symbols

Robert Bruninga bruninga at usna.edu
Thu Oct 4 11:11:50 CDT 2007

> ... just that the APRS spec is a moving target 
> rather than something that was robust right 
> from the time it was released. 

I would say that it evolves and keeps current with the needs of
the community as best it can...

> it sure didn't take very long for the UI-View 
> symbol set too be updated to add the TRACTOR
> symbol... which to me was really a waste of 
> a symbol...

Farming is very interesting these days.  Every big tractor has a
GPS.  Crops are plowed, planted, fertilized, watered and
whatever by GPS.  Once a ham farmer pointed that out to me, it
made sense.  Look in the cab of a modern $100,000 tractor and
you will see some of the most sophisticated GPS technology
avaiable.  It seemed to make sense to give him a tractor symbol
rather than for him always having to explain why his $100,000
tractor shows on FINDU as a car...

> If "you" keep adding a few new symbols per 
> year, the symbol set will be changing almost 
> constantly at a trickle rate for years to come.

I have not been in any rush, because except for the very few
remaining symbols in the basic primary table, all future
additions have to be made with the "overlay" byte.  WinAPRS
could not add new symbols except by exception, Uiview cannot add
any overlays unless someone writes it into an add-on, and so
only XASTIR and APRSdos and APRSscs could see them (and they are
the minority).  I did not want to start having some people using
symbols that others cannot see except for where a compelling
need exists.

Now that the Kenwood in the D710 can display at least overlays
on any symbol, the first new addition was the overlay "O" to
mean OPERATOR present.  We can look at other important needs as

> who is it that decides if new symbol(s) will be added 

I'd be happy to take a look at any new proposals for symbols.
But it is important to recognize that most new additions will be
an overlay character on to a secondary table basic symbol, and
until all client software is upgraded, that maybe only the basic
symbol will be seen by most other users.  So that is why we need
to be careful and organized in how we do this.

Here are some initial thoughts. 

S = Skier
R = Runner
H = Hiker

E = Electric 
H = Hybrid
S = Solar powered

B = Backup Battery Power
E = Emergency power
G = Geothermal
O = Operator Present
S = Solar Powered
W = Wind powered

We should  not RUSH to fill all of the 2900 remaining slots on
"speculation", because then we block any future use of those
symbols.  I prefer to add them cautiously and with plenty of
visibility so that if anyone sees any conflict they can speak


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