Phillip zl2tze at yahoo.com.au
Tue Nov 25 11:48:39 EST 2008

Hi Ian
              Congratulations and welcome to Amatuer radio

To answer your questions there are standard SSIDs for most applications

attached is the standard SSID recommendations 

73 Phillip



Since there are many APRS users on the air, the APRS maps and data can
get very cluttered.  Also, most operators have multiple stations on the
air, such as their HOME, CAR, BOAT, and HT.  It is very convenient to be
able to recognize these typical applications at a glance.

  Here are those common defaults:

-0 Home Station, Home Station running IGate.
-1 Digipeater, Home Station running a Relay Digi, Wx Digipeater
-2 Digipeater [#2 or] on 70CM
-3 Digipeater [#3]
-4 HF to VHF Gateway
-5 IGate (Not home station) 
-6 is for Operations via Satellite

-7 Kenwood D7 HH
-8 is for boats, sailboats and ships (maybe 802.11 in the future)
-9 is for Mobiles
-10 is for operation via The internet only
-11 is for APRStouch-tone users  (and the occasional Balloons) 
-12 Portable Units such as Laptops, Camp Sites etc.
-13 Un-asigned
-14 is for Truckers
-15 is for HF

Originally, in 1992, the first APRS GPS mobiles just transmitted raw
NMEA-0183 GPS stings and so there was no way to insert a SYMBOL byte in 
the pre-formatted NMEA 183 packet.  Hence we defined 14 common SYMBOLs as
defaults to the 14 available SSID's that a mobile could use.  These 
included BIKES, HELICOPTERS, AIRCRAFT, VANS and many others in addition
to the ones above.  This is now OBSOLETE.

In the late 1990's we came up with a better solution and defined the
AX.25 TOCALL of GPSxyz for such use.  In this case, the "xyz" characters
can be used to define any of the hundreds of APRS symbols including
Overlays.   Just look up the xyz in the SYMBOLS.TXT file included in all 
copies of APRSdos (or these days, on the WEB).

Since this GPSxyz concept was so powerful, it completely replaced the
original SSID assignments and so those original NMEA defaults have been
removed from the Documentation.

However the convention for the 6 most useful ones remains and should be
used in the absesnce of any other overriding conditions.  Except for the
TH-D7 and Truckers, the other SSID conventions mark APRS "TYPES" of users
that are independent of the many SYMBOLS they can use.  Thus it is nice
to know HOW someone is getting into the system, whether via satellite,
HF, the internet, or touchtone.  For example, using the -6 only for Space 
applications is so that the global APRS WEB data bases will keep 
statistics and data for when you are operating through the satellites 
separate from when you are working normally.

So stick to the standards above for the obvious applications...  Of course
these are not rigid.  If you have more than 4 digipeaters, use any SSID
you want.  
These are only guidelines...

de WB4APR, Bob

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