[aprssig] Digipeater addresses/spec question

Stephen H. Smith wa8lmf2 at aol.com
Tue Jul 19 19:49:58 EDT 2011

On 7/19/2011 11:07 AM, Alexander Sack wrote:
> Hello:
> If that's the case, why do Source addresses require a SSID while
> Digipeater addresses do not?

Not true!

Any packet station regardless of whether it is a home station, mobile, 
digipeater, igate, or whatever, can either use, or not use, an SSID.   The sole 
purpose of the SSID is to allow more than one station to operate under the same 

Note that an SSID of -0 (zero) is the same as no SSID at all.

For example:

In the greater Los Angeles area, which I just left, there are at least 4 
digipeaters operating under the same callsign (N6EX) with various SSIDs.

I run WA8LMF (no SSID) as my main mobile,
WA8LMF-3  on my TH-D7 handheld APRS radio
WA8LMF-13 as a two meter VHF digipeater/igate at the home station
WA8LMF-2  (30 meter HF APRS over classic 300 baud HF packet)
WA8LMF-63 (30 meter HF APRS over PSK63)

Decades ago, before specialized APRS-specific hardware and software was 
available, SSIDs were used to determine what symbol (house, car, truck, boat, 
digipeater, etc) would be displayed on the recipient's map.  This usage is now 
obsolete, since the APRS-format position report can embed the control codes to 
cause the display of over 200 different symbols.

Details on the symbol control codes are here on my website:

. <http://wa8lmf.net/aprs/APRS_symbols.htm>



Stephen H. Smith    wa8lmf (at) aol.com
=== Now relocated from Pasadena, CA back to 8-land (East Lansing, MI) ===
Skype:        WA8LMF
Home Page:          http://wa8lmf.net

=====  Vista & Win7 Install Issues for UI-View and Precision Mapping =====

*** HF APRS over PSK63 ***

"APRS 101"  Explanation of APRS Path Selection & Digipeating

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