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[aprssig] Compressed, Course/Speed, Weather question

Robert Bruninga bruninga at usna.edu
Wed Nov 10 17:45:07 UTC 2010


> station.  Page 27 (PDF's 37) shows the CSE/SPD and DIR/SPD as 
> the same format Data Extension where the latter is for 
> Weather Reports.  Further, given the Complete Weather Report 
> Format - with Compressed Lat/Long position on page 66 (PDF 
> 76), it would definitely seem to be that the compressed 
> course and speed are in fact wind direction and speed when 
> transmitted by a weather station (_ symbol).
> 
> Is my reading of the spec correct?

Yes, that was the intent.  But who knows which-if-any clients
decode it.
Even if APRS.FI does it, do the D7, D700, D710, FTM-350, VX8R,
VX8DR, VX8G?

Good luck.
Bob, WB4APR

> 
> Here's a sample compressed weather station packet captured 
> from aprs.fi in it's Decoded form:
> 
> 2010-11-10 14:35:49 UTC: N9QGS 
> <http://aprs.fi/?c=raw&limit=&call=N9QGS> 
> >APU25N,TCPIP*,qAC,CORE-2:@101435z/;0Q`9,?J_Z!bg001t045r000p00
0P000h84b10230/georgetownscottcountyweather.org {UIV32N}
>    type: location
>    srccallsign: N9QGS
>    dstcallsign: APU25N
>    latitude: 38.22749825425411 °
>    longitude: -84.55066863380289 °
>    course: 228 °
>    speed: 0 km/h
>    symboltable: /
>    symbolcode: _
>    messaging: 1
>    posresolution: 0.291 m
>    comment: /georgetownscottcountyweather.org {UIV32N}
>    wx:
>       pressure: 1023.0
>       temp: 7.2
>       wind_gust: 0.4
>       rain_24h: 0.0
>       humidity: 84
>       rain_midnight: 0.0
>       rain_1h: 0.0
> 
> Note the course and speed elements outside of the wx: 
> section.  By way of comparison, here's aprs.fi's 
> interpretation of a non-compressed weather packet.  Note the 
> wind_direction/speed in the wx: section.
> 
> 2010-11-10 14:31:40 UTC: CW8596 
> <http://aprs.fi/?c=raw&limit=&call=CW8596> 
> >APRS,TCPXX*,qAX,CWOP-1:@101431z2810.50N/08042.27W_324/001g004
> t066r000p000P000h79b10189.DsVP
>    type: location
>    srccallsign: CW8596
>    dstcallsign: APRS
>    latitude: 28.175 °
>    longitude: -80.7045 °
>    symboltable: /
>    symbolcode: _
>    messaging: 1
>    posresolution: 18.52 m
>    posambiguity: 0
>    comment: .DsVP
>    wx:
>       wind_direction: 324
>       pressure: 1018.9
>       rain_1h: 0.0
>       wind_gust: 1.8
>       temp: 18.9
>       rain_24h: 0.0
>       wind_speed: 0.4
>       rain_midnight: 0.0
>       humidity: 79
> 
> Depending on the answer(s) to my assumption, I'll either be 
> changing my interpretation that compressed course and speed 
> for weather stations actually is the wind direction and 
> speed, or I'll be contacting Hessu to fix up aprs.fi so that 
> it begins treating compressed course and speed as wind 
> direction and speed for weather which he currently doesn't 
> seem to be doing.
> 
> Lynn (D) - KJ4ERJ - Author of APRSISCE for Windows Mobile and
Win32
> 
> 
> 




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