[Xastir] A problem decoding PHG...

[Tom Russo]

On Wed, Nov 15, 2006 at 08:49:10PM -0700, we recorded a bogon-computron collision of the <russo at bogodyn.org> flavor, containing:
> On Wed, Nov 15, 2006 at 10:11:56PM -0500, we recorded a bogon-computron collision of the <kf4otn at ericsatcom.net> flavor, containing:
> > So I ran into a problem tonight that I thought was interesting.  Below
> > is the packet that is received at my station and below that is the
> > decoding of that packet in Xastir.
> > 
> > You will see where we were messing around with the way his PHG was being
> > sent.  At no time did the software decode his PHG properly.  It always
> > displayed the "default".  KE4TZN is running UI-View32, btw.  Anyone have
> > any ideas?
> > 
> > 
> > 
> > KE4TZN>APU25N,K4ROK-10*,WIDE2-1/1:@160305z3535.79N/07720.76W_072/000g000t066r000p000P000b10120h94/PHG7280
> > {UIV32N}
> > 
[...]
> 
> I've noticed that xastir will not *transmit* PHG information along with
> my weather information.  Other stations in this area that run APRS+SA and
> weather transmit one packet with weather info, then a plain station packet
> with PHG info, and I just guessed that for some reason PHG data extensions 
> aren't supposed to be after weather data; but a quick read of the spec just
> now suggests that I'm wrong to guess that.

In reading over the spec again, it looks like in fact weather reports are
not supposed to have PHG extensions attached.  Looking at the 1.0 spec, chapter
5, there's a table of report types and their allowed data extensions.  
According to that table, the only data extensions that weather reports are
supposed to have are wind direction/speed, and   storm data (in the comment
field).  PHG is only supposed to be sent by regular position packets.

That explains why APRS+SA sends out a separate position packet with PHG 
in addition to the packet with weather data (even though that packet
has position, too).  And perhaps why Xastir doesn't look for PHG in a
weather packet.

-- 
Tom Russo    KM5VY   SAR502   DM64ux          http://www.swcp.com/~russo/
Tijeras, NM  QRPL#1592 K2#398  SOC#236 AHTB#1 http://kevan.org/brain.cgi?DDTNM
"And, isn't sanity really just a one-trick pony anyway? I mean all you get is
 one trick, rational thinking, but when you're good and crazy, oooh, oooh,
 oooh, the sky is the limit!"  --- The Tick