[Xastir] NMEA GPS data duplication

[Tom Russo]

On Wed, Jul 01, 2009 at 04:44:44PM -0400, we recorded a bogon-computron collision of the <fmhillhouse at comcast.net> flavor, containing:
> 
> > The ideal would be if the D700 passed *all* NMEA strings 
> > without being told which one to select from the GPS stream.  
> > But it doesn't.  And at this point, Xastir has no way of 
> > doing periodic commands to the TNC to change the type.
> 
> Interesting! The other day I was playing with a D7 (borrowed) and when I
> turned on GPSMON and set GPSTEXT to GPRMC it sent all the sentences anyway.
> The manual mentions the GPMC string is used only for the LTEXT command.

> Of course the D7 is not the D700.

Could be an important difference.  The D700 startup script we have for Xastir 
doesn't actually have GPSMON in it, and I know it never passes anything but
the one sentence that's set in GPSTEXT.

Just looked at the D700 manual, and GPSMON is not listed in the TNC commands.
It does mention something about LTEXT, but it is in fact the case that GPSTEXT
limits what NMEA sentences are passed to Xastir.  And if you watch the packet
monitor, you can see that the APRS firmware is clearly sending GPSTEXT commands
periodically, as the pmon shows "GPSTEXT was GPGGA" and "GPSTEXT was GPRMC" all
the time.

Guess the D7 has a different TNC command set.  Or GPSMON is undocumented in the
D700.  But if that were the case, one would expect that the APRS firmware would
make use of it instead of issuing all those GPSTEXT commands.

-- 
Tom Russo    KM5VY   SAR502   DM64ux          http://www.swcp.com/~russo/
Tijeras, NM  QRPL#1592 K2#398  SOC#236        http://kevan.org/brain.cgi?DDTNM
  In some cultures what I do would be considered normal. 
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