The idea is to move ambient air over the sensor, since any housing will heat up in the sun. Davis and others use what Davis refers to as DFARS - Daytime Fan-Aspirated Radiation Shields (solar-powered) or 24/7 FARS units powered by battery or mains power.
I can’t find a link to it now, but there was a gentleman who published several .PDF files for DIY solar radiation shields using various coaxial piping arrangements. The later ones were pretty elaborate, and might work for keeping the fan far enough away from the lightning sensor.
Unlike many other forums I moderate on the Interwebs. There are two things I am very consistent about and that is free speech and trying to add to a conversation for the topic at hand. The Weather Flow team would very much like to have this forum be a place where everyone can express their personal views, pose questions, and learn.
Having members poke one another offers no value in the forums or to others.
Lets try to stay on topic and refrain from poking one another where things can get heated.
Purchased this one from Ambient but it hasn’t worked so well. The Air fits inside but is tight. It contacts the plates which seems to transfer heat to the Air. Not sure that is the whole problem or if it is just a poor design but I was getting 5 deg high temps in full sun.
I agree with you Hankster. The shields commercially available are to small to have any positive effect. The natural airflow can’t work in those. There is not enough ‘room’ left and a shield that makes contact … you transfer heat.
That’s why a few posts back I asked if we had experts here that could make a 3D design for the Air module big enough that could be 3D printed. Think we should bring together exerts in airflow that can give clues on how the plates should be, combined with 3D cad designers to make the modelling.
The only option that is acceptable with such a big module is a stevenson screen, but those are 5 times the price of the complete station this side of the ocean. Think most people buying a WF station won’t invest that mush.
So “sun” is the key. Keep it out of the sun and away from a heat source and eliminate the need. Your explanation is different from others that have posted misleading information.
This is my new design for my air. First pic, is looking north showing shielding for low winter
sun angle. Second pic below, is fan pulling airflow out. Third pic to the right, is looking up at
air sitting in a twist lock piece from a water cooler cup dispenser. Last pic is air sitting in the
removed twist lock piece. So far it is giving me perfect readings. I will see how the readings do this summer. Also no false lightning detection from fan, and it actually picked up a couple of
strikes from a snow storm I had here.
I’ve got an Ambient radiation shield too… The AIR fits well. However, I did found the pole mount/bracket is a bit flimsy. I overcome this issue by modifying a stainless steel CB antenna mount.
today I sat with a 3d Catia expert and we made some parts for a stevenson screen, well on screen … making it like 25 * 25 cm and simulated the cost via a specialised site
drawing was quick enough but ouchhhhhhh printing those sizes are still way of budget … as long you stay under 15 cm parts it is ok but once you go ever … it skyrockets
story short : costs x times the complete WF station
If you look at my three designs pictured in this thread, they are based on the coaxial design.
The first one with the bubblewrap foil tubes, the fan was from a cheapo laptop cooler and it ran
for about 2 years, only protected from direct rain.(it still runs)
My second and final designs the inner tube is a cup dispenser from a water cooler.
The air fits and is held in the twist lock piece perfectly.
In my final design the outer tube is corrugated poly hot glued in a square around a fan at the top. Fan pulls air from the bottom and out between the two top plates.
I did have it running with a solar panel and used batt, but batt died and just went with 12 v dc
power supply and underground cable.
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