A bit to dry for me

Once again I am plagued by a failure to document problems I encountered and figured out.

Serious problems with humidity

Devoted a good portion of yesterday to getting weewx back into operation after a version upgrade took it down.

Part of that involved me figuring out (again) how to get the weewx extension working that creates the wxnow.txt file that Xastir uses to create and send APRS weather data.

Here’s an example of what Xastir was sending out:
APX219,TNGNXI,WIDE2*,qAR,BASHOR:@071408z3913.63N/09454.49W_166/006g012t051r000P000p000h05b10180

The error is “h05” as humidity is not 5%. The problem is that Xastir wants a two digit humidity data value and wxcn is sending a three digit value.

In examining the old copy of wxcn.py I see the comments I placed in the file:

# fields.append(“h%03d” % int(data[‘outHumidity’]))

# changing value “h%03d” to “h%02d”

… and the line now appears as:

fields.append(“h%02d” % int(data[‘outHumidity’]))

I updated these comments in the new version of this file as it appears in /home/weewx/bin/user/cwxn.py

With the correction, here is what Xastir is now beaconing:
APX219,WIDE2-1,qAR,BASHOR:@071426z3913.63N/09454.49W_166/007g011t051r000P000p000h59b10172

Now the humidity is given as “h59” instead of “h05”.

I am pretty sure that this concludes all the tweaks and fixes I had to make to get weewx working with Xastir to work properly. Time will tell.

A break down of the Xastir/APRS weather data string:
@071426z3913.63N/09454.49W_166/007g011t051r000P000p000h59b10172

@071426z – “07” is the calendar day, “1426z” is the time
3913.63N/09454.49W – location
166 – wind direction
007 – wind speed
g011 – gust, peak winds in last five minutes
t051 – temperature
r000 – rain within last 60 minutes
P000 – rain within last 24 hours since midnight
p000 – rain per last 24 hours (sliding 24 hour window)
h59 – humidity
b10172 – barometric pressure