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[wxsig] Using T238+ with LaCrosse Technology Wx Station

Gerry Creager gerry.creager at tamu.edu
Thu Mar 6 04:23:12 UTC 2008


Will, et al,

William Beals wrote:
> Gerry:
> 
> I hadn't heard about APRS lacking resolution before.  I know for the T238 we
> have had long debates over accuracy, but it has almost exclusively
> surrounded the sensors, not APRS.  What do you feel is lacking?

In the original APRS spec for weather, temperature (and dew point if 
representedvice humidity) is represented at integer level as is 
barometric pressure.  It'd help in the real world for us to see at least 
0.5d degC resolution for temp/dew point, preferably 0.1 degC, and 0.1 
hPa resolution for pressure.  Wind should be expressed with at least 5 
deg of arc resolution and preferably 1 deg, and 0.1 m/s (0.2 knots).

Turns out that the APRS-WX data are getting used operationally, and I, 
for one would love to see better accuracy (which will be 
instrument-mediated) and precision (how we can send the data.

Now, the downside is this: Some/most of the consumer-grade weather 
instruments can't provide the precision we'd love to see.  So that's a 
topic for the next-generation instrument development cycle!

> There are a few things that would be nice to extend within the weather
> formats for APRS.  One of them several folk have asked for is extensions to
> allow broadcasting lightning hits.

Love to see it.  And, direct and diffuse solar, soil moisture and soil 
temperature (arrays, both, from surface to 2 meters deep), as well as, 
perhaps, leaf- or fuel moisture?

> I tried plunking "SGC SWE/SOS" into Google and didn't get any hits that made
> sense.

Bad fingers.  Bad, bad fingers.  Try looking for OGC (Open Geospatial 
Consortium) and Sensor Web Enablement.  It's been a long couple of 
weeks.  I'm finishing up a meeting in Orlando, was in Gulfport MS 
(Stennis Space Center) last week.  Sometimes I just can't type anymore.

While I'm at it, a sales pitch:  Anyone who's not done so, and is 
reporting their data via APRS, please consider joining the Citizen 
Weather Observer Program.  Your data will be greatly appreciated. 
http://www.wxqa.com.  Data for CWOP used to be collected on the APRS-IS 
servers but we're migrating them to their own servers now to separate 
the two services.  Hams who want to route their data to CWOP can and 
should continue to use the servers in rotate.aprs.net (DNS round-robin).

73 gerry

> will
> 
> -----Original Message-----
> From: wxsig-bounces at lists.tapr.org [mailto:wxsig-bounces at lists.tapr.org] On
> Behalf Of Gerry Creager
> Sent: Wednesday, March 05, 2008 8:06 PM
> To: TAPR Weather Station SIG Mailing List
> Subject: Re: [wxsig] Using T238+ with LaCrosse Technology Wx Station
> 
> One project you might be interested in is wview, a linux implementation 
> for the Davis VP2 and Viasala WXT-510.  OK, cool enough, and it's for 
> Linux.  BSD.  Mac. Solaris.  Cool.
> 
> But, if you were to reflash a Linksys NSLU2 for Linux, add a flash stick 
> of a gigabyte, and a USB/serial adapter, and use THAT in place of the 
> PC, it's pretty cool, too.
> 
> Still, T238 is a neat project.
> 
> Will, I'd like to start entertaining other formats.  APRSese lacks a 
> little resolution for real met activities.  Any interest in starting a 
> dialog for what it'd take to generate a new plan, perhaps 
> standards-based (OGC SWE/SOS for the google-inclined)?
> 
> 73 gerry
> 
> William Beals wrote:
>> Lee:
>>
>> I couldn't afford any of those high-dollar weather stations either!
>>
>> Unfortunately, the problem you are having is the same I had.  Outside the
>> Peet and Davis solutions, there are no real standard ways of getting data
>> from those devices to something that could then reformat the data to
>> APRS-ese.  It was that conundrum that finally convinced me to start the
> T238
>> project.  The Peet format for weather data is part of the APRS spec, so if
>> you ever could find one cheap, all you'd need is a TNC and radio.
>>
>> I must confess to have not been keeping up with other weather stations
> once
>> I started the T238.  Does the LaCrosse weather station have some kind of
>> serial output that sends the data out in a known/published format?  If so,
>> then there may be hope of a PC-based converter program available
> somewhere.
>> If not, then you may be pretty stuck.
>>
>> BTW, one minor point I do like to bring up.  Having a PC on 24/7 to do any
>> of your weather data processing is pretty expensive.  At least here in
>> Colorado where electricity is 10 cents per KWH, a 100W PC being left on
> 24/7
>> costs about $7.20 a month.  That adds up pretty quick!  At least, that is
>> how I justified some of the hardware cost to my wife--"Honey, I'm *saving*
>> money with this project!!" :)
>>
>> will
>>
>> -----Original Message-----
>> From: wxsig-bounces at lists.tapr.org [mailto:wxsig-bounces at lists.tapr.org]
> On
>> Behalf Of Lee Mairs (SAG)
>> Sent: Wednesday, March 05, 2008 11:13 AM
>> To: TAPR Weather Station SIG Mailing List
>> Subject: [wxsig] Using T238+ with LaCrosse Technology Wx Station
>>
>> Will -
>> I couldn't afford one of the hight dollar Peet Bros or Davis 
>> Instrument stations - especially after finding a LaCrosse Technology 
>> station on Amazon.com that provides wind speed/direction, indoor and 
>> out door temperature, rain fall and humidity plus the dew point and 
>> wind chill temperatures for only $135.
>>
>> Can you recommend an APRS interface for this station?  I was hoping 
>> to build a T238+ to interface to the LaCrosse sensors, but now 
>> realize that it is probably impossible/impractical.
>> 73 de Lee
>> KM4YY/8
>>
>>
>>
>>
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> 

-- 
Gerry Creager -- gerry.creager at tamu.edu
Texas Mesonet -- AATLT, Texas A&M University
Cell: 979.229.5301 Office: 979.862.3982 FAX: 979.862.3983
Office: 1700 Research Parkway Ste 160, TAMU, College Station, TX 77843





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