Topic: dramatically improve the davis 7714 solar shield

[kobuki]

Stop spouting BS please. It is always beneficial to compare multiple solutions and samples to enhance statistical effectiveness. I'm starting to think that you're just trying to advertise some products here.

[ivano]

Stop spouting BS please. It is always beneficial to compare multiple solutions and samples to enhance statistical effectiveness. I'm starting to think that you're just trying to advertise some products here.

sorry, who are you talking to?

[CW2274]

I'm wondering how a fan-aspirated temperature sensor would fare besides the tested devices. As I understand, these are all passively ventilated.

oh my, the comparison with a ventilated screen is not always feasible, if the wind exceeds 10 km / h the ventilated loses its effectiveness,

There was talk of this years ago, with stock fans being overcome by stronger winds, causing the sensor chamber to not ventilate properly. Not sure how much credence I'd put in that...however, just another reason to upgrade to a stronger fan motor if able. I have no doubt those of us with case fans do not suffer from this "potential" issue. Just food for thought.

[kobuki]

That's interesting. Davis' fan aspirated shield and some others I read the docs of are completely closed (aside from the holes necessary for the forced air flow), the measurement chamber is effectively or literally an insulated plastic pipe. To have a kind of wind at the sensor that negates the effects of the fan is not impossible, but my gut feeling tells me it should almost be. In any case, a constant airflow apparently helps, no matter how it's produced. Having this kind of "self-ventilating" screen is nice, but it's still an Nth order reference to compare anything against, so it would be nice to see a calibrated, traceable sensor besides them.

[CW2274]

Davis' fan aspirated shield and some others I read the docs of are completely closed (aside from the holes necessary for the forced air flow), the measurement chamber is effectively or literally an insulated plastic pipe.

This is indeed the case with the 24hr shield. It has two holes, top and bottom, and is designed for constant aspiration, at least in sunshine, and makes for a poor passive shield. Still, further testing should be "enlightening" if one wanted to give it a whirl.

[ivano]

good evening everyone, data of the days 03-04 / 09/2022
 [ You are not allowed to view attachments ]  [ You are not allowed to view attachments ]
still good, in line with the past days

[vinceskahan]

Is anybody supposed to know what your posts are showing and why we care ?

[ivano]

if you do not care not to look, I did not understand the meaning, it is a test, and it sure is of interest to many users,

[vinceskahan]

You're going to have to explain please.
What are you testing ?
Haven't you reached a conclusion after 'dozens' of posts ?
Is there really anything more you need to provide in terms of tests and data ?

[ivano]

I have come to a conclusion since the first day of testing, and it is this conclusion: if you take a standard davis 7714 and color the interior matte black, the davis 7714 will greatly improve its performance, until it is almost on par with a third generation meteoshield pro
 [ You are not allowed to view attachments ]  [ You are not allowed to view attachments ]  if you haven't grasped this, forget it 

[hmderek]

1 third generation which is not for sale yet

Ugh, now I'm gonna need that too. 

[ivano]

1 third generation which is not for sale yet

Ugh, now I'm gonna need that too. 

that's right, not yet for sale, but in testing at my station

[ivano]

good evening everyone, for those wishing to follow the davis black test, click on this link https://u.pcloud.link/publink/show?code=kZ1LgbVZBf5t5G5lxqzfAfQl1uPiBX1PGNKk#p=1  the data is updated daily, plus you can download all the data from the start of the test

[Mapantz]

Take it for what it's worth, but the inside of the 24hr VP2 shield (which is patented), has a black disc at the bottom of the sensor chamber. I think it's safe to say this isn't just because, but serves a purpose, and it's aspirated, so it's not just for passive performance.

As standard?

Nothing is black in mine, apart from the fan itself.

[CW2274]

Take it for what it's worth, but the inside of the 24hr VP2 shield (which is patented), has a black disc at the bottom of the sensor chamber. I think it's safe to say this isn't just because, but serves a purpose, and it's aspirated, so it's not just for passive performance.

As standard?

Nothing is black in mine, apart from the fan itself.

Yes, came that way. Just to reiterate, this is the 24hr shield I speak of. Do you have that or DFARS?

[Mapantz]

Yes, came that way. Just to reiterate, this is the 24hr shield I speak of. Do you have that or DFARS?

I have the daytime fars.

As far as I am aware, the radiation shield plates are identical on both.

[CW2274]

Yes, came that way. Just to reiterate, this is the 24hr shield I speak of. Do you have that or DFARS?

I have the daytime fars.

As far as I am aware, the radiation shield plates are identical on both.

The plates are the same, but the aspiration is not, as well as the physical structure of the sensor chamber. I've never seen DFARS in person, but believe it is ventilated from the sides as well. The 24hr shield has two holes, top and bottom. It's meant for constant aspiration, unlike the DFARS. I imagine that's why the 24hr has the black disc as well.

[Mapantz]

The plates are the same, but the aspiration is not, as well as the physical structure of the sensor chamber. I've never seen DFARS in person, but believe it is ventilated from the sides as well. The 24hr shield has two holes, top and bottom. It's meant for constant aspiration, unlike the DFARS. I imagine that's why the 24hr has the black disc as well.

Why would the aspiration be different? The aspiration would be exactly the same, it's just the 24 hour one needs batteries and an extra solar panel.

The dfars comes with the plate to put batteries in, and the pcb, if the user ever wanted to convert it to 24 hour. I have never seen anything any different, or with a black plate.

[CW2274]

The plates are the same, but the aspiration is not, as well as the physical structure of the sensor chamber. I've never seen DFARS in person, but believe it is ventilated from the sides as well. The 24hr shield has two holes, top and bottom. It's meant for constant aspiration, unlike the DFARS. I imagine that's why the 24hr has the black disc as well.

Why would the aspiration be different? The aspiration would be exactly the same, it's just the 24 hour one needs batteries and an extra solar panel.

The dfars comes with the plate to put batteries in, and the pcb, if the user ever wanted to convert it to 24 hour. I have never seen anything any different, or with a black plate.

What would you have me say? All I can tell you is what the 24hr shield has...and that's a black plate at the bottom where the air is drawn from. 

[Mapantz]

What would you have me say? All I can tell you is what the 24hr shield has...and that's a black plate at the bottom where the air is drawn from.

You must have some kind of old version or something?!

Current radiations shields are identical. As I said in the previous post; The dfars kit still has the moulded bits for batteries and the pcb. I would just need to buy the solar panel, batteries, battery covers/gasket, and pcb and do a little soldering, and I would have the 24 hour fars.

https://www.scaledinstruments.com/wp-content/uploads/2020/12/R-DFARS_Conversion_V1.2.pdf

^ Identical to dfars.

[CW2274]

I bought my VP2 in 2007. As you can see, they are not identical. The 24hr has more plates, and obviously a black disc at the bottom....

https://www.weatherstations.co.uk/wp-content/uploads/24hr-FARS.jpg

[CW7491]

This welded core is the fundamental difference between the DFARS and the 24hr version …

https://www.scaledinstruments.com/shop/davis-instruments/parts/vantage-pro2-parts/radiation-shield-parts/davis-7345-029-vantage-pro2-24-hr-spars-welded-core/

As CW2274 says, at the bottom of this core, inside the chamber, is a black disc.

[CW2274]

This welded core is the fundamental difference between the DFARS and the 24hr version …

Thank you. I should have produced this in the first place, but spaced it.

[JCA433]

I did the same thing; painted the inside black and this lowered the temperature about 0.6F compared to a Davis 7714 shield not painted black inside.

[ValentineWeather]

I painted my 7714 interior black back in 2015 or 16, not every louver but probably wouldn't hurt.  Many of the high-end shields have black interiors now reducing the scattered light is the idea. I don't have any data to show it worked but remember at the time I was pleased with the results. I just recently got the 7714 back out after discovering these little jewels. Pretty sure they use a modified sensirion.
 
https://www.amazon.com/dp/B09CNTPHLN?psc=1&ref=ppx_yo2ov_dt_b_product_details

I have a sensor off the Bayga down inside one of my 2-FARS shields and they follow right along with the sensirion SHT-31. Love the easy-to-see bright-colored console.   
I've got 4 of them around the house with sensors measuring different areas. I even gave a couple units to friends, I'm that impressed.