[aprssig] A New "Space" Trend ?
Stephen H. Smith
wa8lmf2 at aol.com
Fri Feb 6 19:15:22 EST 2009
KB5ILY - Travis W. Burton wrote:
> Maybe I haven't noticed it in the past, but I have noticed several new stations
> inserting a space between CALL and an SSID. Plus the SSID is one or two
> letters rather than numbers. Only one example of this in my stations list
> would be:
> NT5RN A
> NT5RN B
> NT5RN C
> NT5RN AB
> NT5RN-B
> NT5RN-C
>
> Is space a valid character per the spec ?
>
>
APRS is an application layered on top of the 30+ years old AX-25 packet
radio protocol and standard.
For **RF** operation, the SSID format MUST conform to the underlying
AX-25 standard, and be a hyphen and number between 0 and 15. [The
packet standard only provides a single 4-bit nibble for the SSID field,
meaning only 0000 through 1111 ( binary equivalent of 0 to 15 decimal)
will work.]
APRS **Internet** operation is NOT constrained by the limitations of
AX-25 and the packetizers/de-packetizers in TNCs. (You are just passing
strings of text through a Telnet connection to an Internet server.)
Any arbitrary characters can be placed in the SSID field, -IF- you don't
want the packet to be gated to RF.
For example the three instances of UIview in my ham server setup that
receive-only off RF, and never transmit, use the "fake" SSIDs of
WA8LMF-16, -17 and -18 to conserve the "real" SSIDs for on-air RF use.
The fourth instance of UIview which does transmit on RF uses -15.
------------------------------------------------------------------------
--
Stephen H. Smith wa8lmf (at) aol.com
EchoLink Node: WA8LMF or 14400 [Think bottom of the 2M band]
Skype: WA8LMF
Home Page: http://wa8lmf.com --OR-- http://wa8lmf.net
World Digipeater Map
http://wa8lmf.net/APRSmaps
JavAPRS Filter Port 14580 Guide
http://wa8lmf.net/aprs/JAVaprsFilters.htm
"APRS 101" Explanation of APRS Path Selection & Digipeating
http://wa8lmf.net/DigiPaths
Updated "Rev H" APRS http://wa8lmf.net/aprs
Symbols Set for UI-View,
UIpoint and APRSplus:
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