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RE: [wuhu_software_group] Re: "homebrew radiation shield"

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  • Jeffrey C. Le Doux
    Chronarch33, et.al., Before I sent my note I checked the 4 closest stations as well as the NWS analysis graphs. There is one station that is way out, but
    Message 1 of 5 , Aug 29 2:40 AM
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      Chronarch33, et.al.,

      Before I sent my note I checked the 4 closest stations as well as the NWS “analysis” graphs.  There is one station that is way out, but the rest are within a degree of mine, and mine lays right on the analysis graph.  There is very little time when the sun has the opportunity to shine on the thermo/hygro sensor, and that was even before my modifications.  The most important modification, apparently was the addition of the aluminum foil on the cover to reflect the heat.  The holes merely provide a way to circulate the air.  Later this morning I will photograph the setup, and submit those photos.  (The holes will probably not be visible, but we will see. 

      Jeff L.

      The WiltonWeatherGuy

      KMEWILTO1

      CW5246

       


      From: wuhu_software_group@yahoogroups.com [mailto: wuhu_software_group@yahoogroups.com ] On Behalf Of chronarch33
      Sent: Wednesday, August 29, 2007 1:38 AM
      To: wuhu_software_group@yahoogroups.com
      Subject: [wuhu_software_group] Re: "homebrew radiation shield"

       

      Jeff & Others,

      I have a question for you and a few comments. I was reading through
      CWOP's manual and believe I noticed that errors can be as much as 6
      degrees before your data gets flagged by MADIS as being strange. Have
      you compared your values with a nearby NWS station throughout the day
      as a sanity check? I only ask this because I have a 2308 station as
      well and have been struggling for months trying to get "quality"
      data. I finally signed up for CWOP last week so I should start
      getting my QC data this week. For my modifications I started off by
      drilling holes in the cover for the 2308 so rain could not get in but
      air would be able to pass through. This did not do much. I have
      always kept it in the shade though because the temp spike were 10-15
      degrees when sunlight touched it. I then proceeded to purchase one of
      those manufatured gill plate/plastic dish radiation shields from
      AMbient Weather and moved the sensor so it was in the sun. I only
      get morning to early afternoon sun though because I live on a green
      belt so the sun dissapears behind the trees after lunch time. This
      helped a bunch but I would still get around a 5 degree spike when the
      sun hit and then it would flatten out. So I made another
      modification by cutting a hole in the 2nd to top plate and added a
      8mm 75 CFM DC computer fan that pulls the air up thus making it an
      aspirated shield. Now my temps read within exact to no more than 3
      degrees off at times from the NWS station at the airport. I
      originally had a 5 watt solar panel to run the fan but then I thought
      it would be a great idea to get a tractor/lawn mower battery to make
      it 24 hour aspiration. Well with the green belt issues the battery
      would croak after about 3 days. HAHA. SO I bought a 1.5 Amp small
      battery charger that trickle charges and acts as a DC power supply.
      Seems to be working so far. I have done all this over the past few
      weeks. Pretty fun modification. It cost me just around $120 for all
      the various goodies. So add that to the $79 for the station I now
      have a pretty decent setup for around $200.

      Here is my station data

      http://www.wundergr ound.com/ weatherstation/ WXDailyHistory. asp?
      ID=KWAARLIN6

      --- In wuhu_software_ group@yahoogroup s.com, "Jeffrey C. Le Doux"
      <jefcled@... > wrote:

      >
      > WUHU ,
      >
      > I did not want to say anything until I had several sunny days on
      record.
      > That has now occurred. I have a small shelter (will photograph
      tomorrow)
      > and the aluminum foil wrapped perforated cover that came with my ws
      2308
      > weather station ( La Crosse ).
      Despite my connectivity problems the
      following
      > is what I have been getting for weather quality reports from CWOP.
      >
      > DATE UTC * ALT * POT TEMP * DEW PNT * DD *
      FF
      >
      > * (MB) * (DEG F) * (DEG F) * (DEG) *
      (KNT)
      >
      > 28-AUG-2007 Errs * 0/35 * 0/35 * 2/35 * 0/35 *
      0/35
      >
      > DATE UTC * ALT * POT TEMP * DEW PNT * DD *
      FF
      >
      > * (MB) * (DEG F) * (DEG F) * (DEG) *
      (KNT)
      >
      > 27-AUG-2007 Errs * 0/46 * 0/46 * 1/46 * 0/46 *
      0/46
      >
      > DATE UTC * ALT * POT TEMP * DEW PNT * DD *
      FF
      >
      > * (MB) * (DEG F) * (DEG F) * (DEG) *
      (KNT)
      >
      > 26-AUG-2007 Week *-0.5(0.48)* 1.5(3.74)*0. 82(3.47)* -6.7(
      94)*0.05
      (1.53)
      >
      >
      >
      > Note that times are in UTC. The values displayed are 'Observed
      (error)'
      >
      > The error value is 'analysis - observed'. I.e. if your observed
      value is
      > higher than the computed value, then the error will be negative.
      You have to
      > pick out the reading that is in error. The row with the time
      of 'Smry' is a
      > daily summary and the data is 'mean(standard deviation)' for each
      > observation during that day.
      >
      > The 'Week' row is the summary for the preceding 7 days.
      >
      >
      >
      > As you can see, no temperature errors at all, and we have had
      plenty of sun
      > for the last couple days. The ones before these two are equally
      impressive.
      >
      >
      > Jeff L.
      >
      > The WiltonWeatherGuy
      >
      > KMEWILTO1
      >
      > CW5246
      >

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