[aprssig] NWS ON rf

Pete Loveall AE5PL Lists hamlists at ametx.com
Fri May 8 18:22:53 EDT 2009

> -----Original Message-----
> From: Steve Dimse
> Sent: Friday, May 08, 2009 4:57 PM
> This packet appears to be an APRS Internet System packet. Although
> some programs have been written that can take an APRS IS packet and
> transmit it in the APRS IS form, AFAIK none has been deployed outside
> of testing. Furthermore, the use of the lowercase q in the path makes
> it a deviation from the AX-25 standard. Tests have shown most TNCs can
> handle it, but on general principles it should not be sent.


All IGates transmit using 3rd-party format (see APRS spec) which includes the transmitting station's callsign since that is the base packet.  Q-constructs and the rest of the APRS-IS path are NOT to be transmitted on RF and would be in violation of the APRS spec.

The software you are using apparently does not show the transmitting station of a packet when a 3rd-party packet is received (I believe UI-View does not display the IGate station when viewing messages).  To identify the IGate if your software does not display this with the packet requires opening a "TNC" window if available to display the true AX.25 packet.

If the 3rd-party header is actually DVNSWO>APRS,qAS,WXSVR as was originally posted, then the IGate software is in error.  According to the APRS spec, the 3rd-party header should be DVNSWO>APRS,TCPIP*,IGATECALL or DVNSWO>APRS,TCPIP,IGATECALL* where IGATECALL is the callsign-SSID of the IGate gating to RF.  Again, this is in place for simple identification of the network the packet came from as well as easily identifying the station that gated the call to RF.


Pete Loveall AE5PL
pete at ae5pl dot net

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