Should the temp sensor that came with my WH1081 be placed out of direct sunlight?
Thanks.
Most Definately. Direct sunlight will cause the readings to be artificially high. Also do not mount it above asphalt/concrete. It is best to mount it inside a radiation shield of some type. do a search on this subject and you will find many different types that you can build or purchase.
Hope this helps.
Bill
Why do you see temp sensors built into the anemometer, cos theirs noway you can have a anemometer in the shade
If they’re built in to the anemometer inside of a radiation shield then it is OK. The key is they be inside the shield. I don’t think I’ve seen a all-in-one sensor package that didn’t have the radiation shield on the temperature/humidity sensor.
If there is an all-in-one sensor unit that does not have a radiation shield I wouldn’t recommend it. To keep the temperature sensor out of the sun would also mean shielding the wind instruments.
I dont think the Ventus W155 is shielded
http://www.ventusdesign.com/products/w155-weather-station-with-rain-gauge-and-anemometer/
Another key is that even if it’s in a shield, it, at the very least, should be in a place where it can get wind while the sunlight is on it. I have MANY wind breaks on my property; makes it difficult to get good placement. My solution was a modification of an Ambient SRS100LX I bought for my TE923W and it’s TS34C thermo/hygro sensor. I modified it to aspirate it with a fan via a solar panel driving the fan.
It’s a bit daft, actually, unless you want to use it as a solar radiation detector.
Just for fun, I plotted the difference between the temperature sensor in the anemometer and the reasonably well shielded air temperature sensor. The horizontal axis is the compass bearing, from North at left through East, South, and West to North again at the right. The vertical axis is elevation from the horizon at the bottom to the zenith at the top. For each temperature reading, I plotted the sun’s position with a colour that depended on the difference between the anemometer’s temperature sensor and the air temperature. The result clearly shows the treeline around my station.
My anemometer is the AAG unit, in which everything is enclosed in a plastic housing. Totally useless for air temperature readings.
And, before anyone points it out, I know that all those trees in the image are messing up my wind readings. I am planning to move the anemometer to a slightly better location, but, since I live in a small clearing in a forest of 120-foot trees, I’m never going to get an accurate wind reading.
Mine came with a radiation shield and I placed it in the sun with my anemometer and even with the radiation shield it produced way to high of a reading! I would not put it in the sun at all! North end of the house for sure.
its not much of a radiation shield that comes with it, thats the problem
this is very true
Is there a difference on the height of a temp gauge from the ground? How far off the ground should I have my sensor? I just moved it because it was reading way to high being on the ne side of the house. Its now on the north end of the house right below a bedroom window. It looks like my max temp today was 71.4 while happy valley got 1 degree warmer then me. Happy Valley usually is 2 degrees cooler then my station, and the other closet station got 3 degrees warmer then me. Should I put the sensor higher? Thx
http://www.wunderground.com/weatherstation/WXDailyHistory.asp?ID=KORPORTL110
perfect thank you
I see that it says the rain gauge should be about 2-3ft off the ground in a open area. Would you know if it actually matters if its on the roof in a open flat area rather then 2-3ft off the ground in a open area? Would this make much of a difference?
thx
Likely it would…the roof would reflect quite a bit of heat depending on the construction of the roof.
Using asphalt shingles would definitely skew the temperatures during the day, so much so that I don’t think even a fan aspirated shield could completely help.
ummm i think you were thinking that I was talking about a temp sensor… I am wondering if having a rain gauge on the roof make a difference then having it 3ft off the ground like it says to? Plus its not on asphalt shingles, its on where a chimmy used to be. It is now covered by a metal cover, and the rain gauge is screwed down level on that…
Yes it would.
I recall someone once posting a link to an interesting study on the relation between height and measured rainfall, but I can’t find that at the moment. It might have been prodata, but I’m not at all sure.
The recommended height seems to vary between countries. I understand that the UK Met Office recommendation is 12" (30cm), as mentioned here. To achieve that with my VP2 I used an extra rain gauge base to allow the ISS to be split, with the rain bucket almost on the ground and the temp/hum/Tx at around 4’ (1200mm).
Yes, that’s it. Thank you.
How far away from buildings should the sensor be placed?
Is 2 meters enough?