Topic: bird feeder radiation shield

[funsutton]

Has anyone ever used a bird feeder for a solar radiation shield?

I found this at Lowes and wonder how it might do (without the plexiglass of course):

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Since it's wood, I'd think it won't get too hot and heat up the sensor. Also it has ventilation.

Aiming the front side to the north, would something like this work for an ambient temp rh sensor?

[Mandrake]

You'd have to paint it white to reflect the Infra red heat from the sun (otherwise the wood will still heat from the sun)
However it would crudely work if you wanted to use that to house a WH32 external temperature sensor.
It wont be as effective as a real radiation shield but it would be better than nothing!
The primary issue is that it would not allow air flow, though I suppose you could drill lots of holes in it?

[galfert]

You are better off with the Davis 7714 as a radiation shield. But if that is still too costly then you can get the radiation shield from Acurite. I'm not saying these will perform equally. Test have shown that you can do even better than the Davis 7714 with the Barani Meteoshield Pro, but that is a huge price difference also.
https://www.acurite.com/solar-radiation-shield.html
https://www.amazon.com/AcuRite-06054M-Temperature-Humidity-Radiation/dp/B01M64ISDE/

[funsutton]

While money is certainly a consideration, I guess, being new to this, I just failed to understand exact the purpose of these solar radiation shields, other than to keep direct sunlight off of the temp rh sensor.

Thanks for the input from both. I'll keep that in mind.

[galfert]

The idea is not to keep sunlight out. The idea is to measure ambient air that is in direct sun without it being skewed by radiant heat. Radiant heat is the heat that is generated after a surface has had prolonged exposure to sun radiation and it will be different depending on that surfaces ability to absorb radiant energy. The idea is to measure the air temperature in direct sun but with just enough shielding that the shade provided is not causing the temperature to drop because constant new ambient air is being provided to the sensor (because of wind). What you want is to prevent heat radiation from direct exposure of the sensor. That is why sensors are white and radiation sensors and Stevenson Screens are also white. The goal is also to allow for air to circulate so that you are actually measuring the real ambient temperature. A solid structure that provides shade and does not allow for air circulation is not going to allow you to properly measure the ambient air that is in direct sun. Think of it this way...if you want to know what the temperature is outside you could run out of the house with your temperature sensor in hand and then take a quick reading in direct sun quickly before it has had a chance to warm up due to prolonged solar radiation. Being in the shade is not adequate because ambient air temperature is different in the shade. You want that hot ambient air to be allowed to pass through to the sensor. This is why more expensive solar radiation shields have active fans and they are called fan aspirated radiation shields. It is the job of the fan aspirated radiation shields to constantly provide ambient air. These fan aspirated radiation shields never blow air onto the sensor...rather they suck air in and over the sensor. The placement and air flow direction of the fan is part of the critical design. Fan aspirated radiation shields are expensive and most stations can get by with regular radiation shields (no fan) if there is adequate circulation. .

[funsutton]

Thanks galfert, that helps and makes a lot of sense.

[Notsorusty]

You will also not get these guys upset! 

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[WA4OPQ]

Currently on sale for $19. Nothing in the price range matches it.

http://www.ecowitt.com/Others/115.html

[galfert]

Currently on sale for $19. Nothing in the price range matches it.

http://www.ecowitt.com/Others/115.html

I stopped recommending the RS-00001 radiation shield because the usage results were worse than using a WH65. You don't invest in separate components to get worse data than the WH65 all-in-one. If you are going to get separate components then the Davis 7714 is the cheapest solution that makes it better than the WH65.

Ecowitt should (as in I hope they do) come up with a better radiation shield, especially now that they are about release a SHT35 based sensor which is the WH32-EP.

[WA4OPQ]

Thanks for the info, I wasn't aware.
As much as I'd like the Davis, the Acurite is more in my budget.

[Bushman]

You can make a radiation shield for under 5 bucks.