Economy Radiation Shield

[SLOweather]

mackbig, I thought about doing the same thing you mention, but my Temp Sensor/Fan/rain heater locations are a good 75 feet apart from one another, and I would have to run a wire under a sidewalk.

Easy... dig 2 holes on opposite sides of the sidewalk. Attach a wand or pipe (1/2" will do) to a garden hose. Use water to jet a tunnel under the sidewalk. If you really want to, use a wet/dry shop vac to suck up the muck as it's washed out. The pipe can either be as long as the walk is wide, to work from one side only; or half that length and work from both sides.

[weather1967]

Good job  Dan
I thing it is better to put pc fan 12 VDC to suck air from sensor and to put air above.
I have build like this and the measurement it is the same like Davis weather station

http://www.geocities.com/peristerimeteo/radiationshield.html

[DanS]

Good job  Dan
I thing it is better to put pc fan 12 VDC to suck air feom sensor and to put air above.
I have build like this and the measurement it is the same like Davis weather station

http://www.geocities.com/peristerimeteo/radiationshield.html

Thanks Dimitris. I understand your statement about the fan above drawing the air out may be better. I am just experimenting with this setup and it will be changed some more (reason for the 2-sided tape). I am placing the fan below first, blowing upwards, to see if the sensor just needs fresh air to be accurate. I'll run like this for a while and make recordings then rebuild with the same fan moved to the top, blowing out. I have a feeling, that I personally want to confirm, that just keeping the air fresh and moving across the sensor will give the same results. I have to see for myself. Once all is done then I'll build a better (no tape used) shield constructed to the best results of these tests. I have nothing but lots of time these days and I'm enjoying this WX hobby and all there is to learn from it. 

Cheers,

Dan

[DanS]

Well, when all else fails, tear it apart.  

The more I looked at my setup, the more I thought I could get chocolate in my peanut butter.  So I took the radiation shield apart, took the "stick" out of it that the sensor was attached to, crammed both the OS and LaCrosse sensors up into the shield, put a solid bottom piece on it and it is done.  You can see bits of this process on my web cam:  http://www.wunderground.com/webcams/Slowmodem/1/video.html?month=03&year=2009&filename=current.flv

The sensors are touching the sides of the shield in places.  This will probably affect it somewhat.  However, it's supposed to be made of low-heat-conductivity material, so I think the shade effect will be much more than the conductive effect.  We'll see.

Of course, placing a fan on top will require a complete disassembly again.  But I'm getting good at it!
No disassemble!  No disassemble!

Cool Greg, I would like to hear what happens with it setup like that. I can only guess but imagine you should get good results like that. It will be interesting to see if there is an interference concern between the 2 sensors being so close to each other. If no problem then you've answered a lot of questions asked about available room inside to do what you've done.
You do have to watch out for little "LaOregon" sensors running around the yard though.

Dan

[DanS]

Both of mine are in backyard relatively close along the same run between the border fence and interior privacy lattice fence.  

Hmmm, just had an idea, I could acquire one of those highway sized solar panels mentioned earlier (6 feet by 6 feet), angle it towards the sun, but out of my "view", my neighbour who had conerncs about my little white radiation shield would get a kick out of that...  I could get some of those fallout shelter signs too.

Andrew



Another option is to construct a radiation sheild that looks like this one for your "neighbour" to enjoy.

 

[SlowModem]

Well, it's been nearly 24 hours and all is well.  The two sensors are tracking practically identically.  Maybe all I will do back there now is trim the grass (if I can get some to grow there) and change the  batteries this fall.  (I really love it when things work like they're supposed to!).

http://www.wunderground.com/cgi-bin/findweather/getForecast?query=35.685%2C-84.706

Number 1 and 2 on the list at the bottom to compare.

Greg

[weather1967]

Dan ,i had experiment a long time about it ,i had put the fan to put air over to sensor but it is terible mistake ,because i saw to second radiation shield the temp to go up slowly-slowly with the pass the day with sun,and the radiation shield with the fan to air flow over to sensor it is stable .
Fan must to suck air from the sensor and to air flow above ,and the Davis radiation shield ,fan suck air from sensor and air flow above

[sam2004gp]

Perhaps we should get Dimitris to build all of our FARS for us for now on.  He seems to do a good job as well.

http://www.geocities.com/peristerimeteo/radiationshield.html


P.S.
Don't worry Lars, yours are just as good.    I just wish  that the free Solar Powered FARS idea had worked out. 

[tweatherman]

It still looks like you getting some solar radiation on the sensor.

Tim

[Axelvold]

Perhaps we should get Dimitris to build all of our FARS for us for now on.  He seems to do a good job as well.

http://www.geocities.com/peristerimeteo/radiationshield.html


P.S.
Don't worry Lars, yours are just as good.    I just wish  that the free Solar Powered FARS idea had worked out. 

Thanks Sam

It seems to work very well, it is only showing 1 degree Celsius more than a station from the Swedish meteorological institute, and this with a clear blue sky and a shining sun

[DanS]

It still looks like you getting some solar radiation on the sensor.

Tim

Yeah and it's been driving me (even more) crazy locating the source until yesterday. It turns out to be the translucent properties of the bowls letting diffused light in. These are too thin. I can watch a zoomed in temp graph updating every minute or so while blocking the sunshine and see changes. This makes me wonder, thickness of the bowls...hmmm. Always a suprise. I'm going shopping again for new bowls, this time checking thickness and translucent properties as another spec. Store owner may wonder what I'm doing as I'm holding dinnerware up to the lights.   

Dan

[sam2004gp]

.......Store owner may wonder what I'm doing as I'm holding dinnerware up to the lights.   

Dan

Just tell him your were born in the United States, he will understand.

[DanS]

he he, usually just seeing me as a foreigner keeps them from asking but fun to watch expressions sometimes.

[sam2004gp]

Out of meaness, have you ever said something "dirty" in public, since they may not understand english?

[DanS]

You must think the same as I do because I thought it would be funny to say something "dirty" to someone's face thinking they wouldn't understand. Use the language barrier as a fun thing. Too many speak or understand to take that chance.

[DanS]

Dan ,i had experiment a long time about it ,i had put the fan to put air over to sensor but it is terible mistake ,because i saw to second radiation shield the temp to go up slowly-slowly with the pass the day with sun,and the radiation shield with the fan to air flow over to sensor it is stable .
Fan must to suck air from the sensor and to air flow above ,and the Davis radiation shield ,fan suck air from sensor and air flow above

Thanks Dimitris. That is good to know. Are you saying that when you mounted the fan below, blowing up ,that the temperature readings were very slow updating? I think I understand that you're telling me the best way is to mount at the top blowing out. Don't blow across the sensor but draw it across to the fan. Right?

Dan

[DanS]

Dan ,i had experiment a long time about it ,i had put the fan to put air over to sensor but it is terible mistake ,because i saw to second radiation shield the temp to go up slowly-slowly with the pass the day with sun,and the radiation shield with the fan to air flow over to sensor it is stable .
Fan must to suck air from the sensor and to air flow above ,and the Davis radiation shield ,fan suck air from sensor and air flow above

Thanks Dimitris. That is good to know. Are you saying that when you mounted the fan below, blowing up ,that the temperature readings were very slow updating? I think I understand that you're telling me the best way is to mount at the top blowing out. Don't blow across the sensor but draw it across to the fan. Right?

Edit (6 hrs. later): I decided the way you described sounds the best and tore my down and rebuilt it with the fan on top. (and replaced all the 2-sided tape with screws).

I'll let it go like this for a while to see how it does.
Thanks again Dimitris. Cheers! 
DAn


Dan

[weather1967]

Τhank you Sam and Dan.
Dan there is some good ways about it ,if i understand well for the air do not go buck to sensor again like ping-pong 
You can to put one dishes over to fan with hole like this ,and to put the sensor inside a PVC f 100 .And you can paint black color inside the dishes for the sun radiation do not go pass the white dishes ,it is not necessary to me because i have the PVC tube for this reasons ,but you where do not have PVC tube it will be great to paint black color inside the dishes.With photoshop the third photo you can see what i mean.

[DanS]

I can't tell from your photo, do you have ventilation holes through the sides of the PVC or is it a solid piece top to bottom?

Dan

[weather1967]

Νο no PVC it is solid piece top to bottom
Just holes i have at first dish over to fan for the air go above to second roof dish and after to go out side
My design at first radiation shield it this ,at second third radiation shield where i build i put and another third dish above

[DanS]

Good drawing. Helps to understand your design. Very well designed too. I can see a lot of thought went into that.

I saw on another post where someone used 4 inch PVC about 6 feet long. He stood the PVC upright and painted a small part of the top black and all the rest white. He mounted the thermo-hygro sensor near the bottom and made a vented cap for the top. The thinking was that the black paint up top would heat up from the sun and create and thermal updraft bringing in the ambient air from below. Pretty clever. I never heard the results but thought that was interesting.
Good talking with you Dimitris and thanks for sharing the great idea.

Dan

[weather1967]

Thanks again .Good talking and with you Dan
It is beautiful thing people with same hobby from all over the world to sharing ideas about  meteo equipment.

[TonyV]

Better not let momma catch you though. She might hang you up outside to use as a wind sock.

Like this one? 
http://www.bowkera.com/wyoming_windsock.htm

Tony

[DanS]

Now that's a heavy duty windsock!

[sam2004gp]

FYI: I have found and purchased a 12Volt Solar Panel that does power my 12Volt computer fan.  Total cost so far $46 US Dollars.