Author Topic: Barani pro passive shield  (Read 19572 times)

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Offline Jorginho

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Re: Barani pro passive shield
« Reply #450 on: August 20, 2020, 07:16:41 AM »
Hoezo? Gewoon primen, dan met mat zwarte verf die geschikt is voor kunststof verven en klaar. BTW: heb jij stijgerbuizen gebruikt om je windmast etc te maken? Grappig: vandaag is mijn materiaal binnengekomen op de boerderij. Ik heb steigerbuizen aangeschaft. Aluminium. Ik kon er zo weinig over vinden, dat niemand die gebruikte om een mast te maken van  10 m hoogte. Ik heb dus ook niet kunnen vinden of gegalvaniseerd metaal beter is dan  aluminium. Om het hanteerbaar te houden heb ik 33,7mm/3 mm aluminium gekozen. Een van 6 en een van 4 meter. Anders krijg je een dergelijk gevaarte niet omhoog vrees ik.

In English (to the paint): I will use a black matpaint after priming the screen, suited for hard plastics. I used exactly the same paint but white for my screens that mimick the Vaisala. Not only  do they  perform really well as compared to the  real Vaisala our KNMI uses, it also kept for 13 years. Just last week I noted the paint would come of and I had to redo it again.
« Last Edit: August 20, 2020, 07:24:03 AM by Jorginho »

Offline hmderek

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Re: Barani pro passive shield
« Reply #451 on: August 20, 2020, 07:36:01 AM »
Hoezo? Gewoon primen, dan met mat zwarte verf die geschikt is voor kunststof verven en klaar. BTW: heb jij stijgerbuizen gebruikt om je windmast etc te maken? Grappig: vandaag is mijn materiaal binnengekomen op de boerderij. Ik heb steigerbuizen aangeschaft. Aluminium. Ik kon er zo weinig over vinden, dat niemand die gebruikte om een mast te maken van  10 m hoogte. Ik heb dus ook niet kunnen vinden of gegalvaniseerd metaal beter is dan  aluminium. Om het hanteerbaar te houden heb ik 33,7mm/3 mm aluminium gekozen. Een van 6 en een van 4 meter. Anders krijg je een dergelijk gevaarte niet omhoog vrees ik.

In English (to the paint): I will use a black matpaint after priming the screen, suited for hard plastics. I used exactly the same paint but white for my screens that mimick the Vaisala. Not only  do they  perform really well as compared to the  real Vaisala our KNMI uses, it also kept for 13 years. Just last week I noted the paint would come of and I had to redo it again.

I guess the paint part doesn't have to be that difficult. I just recall that I looked into it related to model building with internal led lighting at some point, and there were quite a few options.

I'll PM you about that Dutch part. ^_^

Offline mauro63

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Re: Barani pro passive shield
« Reply #452 on: August 20, 2020, 09:10:01 AM »
Hi. I know very well it is said to be the shape. But has there been any research on both the claim and the  total effect? If it is the Helical shape, than why did the former version which if I am correct was helical too not performing significantly different to the 7714 Davis? I am very critical of it and personally I actually think I like the Barani system a lot. But as of now I am least interested in the shield of all things actually because you can get a very good performing screen for 40 euro's. You can make it yourself functioning even better with some effort for 20 euro. I did. It performs on par with KNMI Vaisala screens which are also black inside btw. Something really has to a whole lot better if it is to cost 250 euro. I feel I am sceptical that a very exotic looking shape with a good story behind it could be setting me back 250 euro where in fact it is simply the black innards that are responsible for 90% of the difference.
I have not found any research that provides a clear indication as what does what but I also did not look hard to be honest. I think if I want to buy a Barani complete setup it has to be ordered with the Pro shield so I'll probably will get it anyway.

I would in all likelihood still end up with the Vaisala screen anyways because to me it is much more important to compare with KNMI  stations, which is a reason tha t even though I have an aspirated Davis screen in my attick I never used it. Why would I deviate from what our Metoffice uses if comparing with those stations is my goal? So suppose I get the Meteoshield pro nothing stops me from comparing it under high radiation situations (in juni of next year I suppose) say from 1-21 june and do the same thing when I painted it white fro 22 june to say the 13 th of July or so. It might give us an indication.

As to the Davis 7714. Sure it costs 110 euro but is there a reason why not to buy this one from the Davis, the passive one for the Vantage Pro2? Paint it black inside and not just the lower plates. From what I know you simply do not want any reflections landing on your sensor. So every plate needs to be black inside. I did it and found it easy to do, but may be I am being oversimplistic here. That could be true.

https://www.wetterladen.de/davis-schutzgehaeuse-6828-fuer-thermo-hygrosensoren?c=1140

I am a fan of Meteoshield Pro but I must say that I find your speech coherent

if the intent is to have a more reliable comparison with the instrumentation used by the official meteorological network of your reference, it is right and correct not to try to stray from the performance of the latter.
The fact remains that research must always be aimed at improving performance, and not at equaling it.

By way of example, a couple of years ago, a well-known Italian metrological institute, partner of WMO, conducted a series of studies at high altitude to verify the performance of official shields, of professional companies, in conditions of the snowy and non-snowy ground.
from those studies, which are unfortunately not publishable, even though I have them, it emerged that, compared to a Meteoshield Pro, in conditions of snowy ground, the screens of one of the most used companies in the professional field, suffered from overestimates of more than 3 C compared to to the Pro, which had an overestimate of 1 C compared to the reference shield.
what happened then was the removal of all those screens, I do not mention the company name, which were replaced in a short time

Mauro

Offline Jorginho

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Re: Barani pro passive shield
« Reply #453 on: August 20, 2020, 09:35:36 AM »
Mauro, I do agree with both things of course. Getting rid of radiation errors should be the goal. But it is a very difficult and complicated matter. And there is no good or bad choice for amateurs here. Very few are so lucky to have a farmer nearby providing grassland to setup your system out in the open free of charge like I did. In fact I have several farmers in my neighbourhood. So to me it is essential since I have the same surroundings to come as close as possible to the KNMI as this is my reference. I cannot compare to cities surely not when radiation plays a big role. When you are however measuring things in the cities it becomes a lottery and I think money permitting your would do well to eradicate as much of radiative and other "errors" if you want to measure as correct as possible.

Interesting story on the screens with snow covered ground. These indeed gave me the most extreme differences due to radiation in the past. Some years ago I measured -17,2 C in february with snowcoverd ground (just 7 cm btw) and drove around that night. It was amazing to see how every tree in our flat and open landscape made the mercury jump by 5-7 C! so -17 to -18 C where I drove and one tree and boom: -11 C. Which  was exactly the temperature in villlages and cities. -11 C. Every  little bit of wind made the mercury jump too by  3-4-5 C. I recorded every minute. So at 7.01 after a small gust of wind, may b 0,9 m/s made the mercury simply plumeted!
7.01: -13,3
7,02: -14,0
7.03: -15,2
7.04: -16,3
7.05: -16.5
7.06: -17,2

So the gust just mixed up some air around the screen, the response (Vaisala) was incredible. It also went up with wind just like that. Now this also can  be suspected of a screen that is to open. In which case the instrument itself radiates heat away hence you get an instrumeent that is in  fact colder than the air surrounding it. But that would also mean that in summer it would overheat because radiation could all to easily enter the screen. Which is not the case. Also the temperature was similar to other KNMI stations situated more inland. These were a few tenths of a degree colder.

When we look into the study  done in Algeria in 2008 there was a small, but significant note on the Davis 7714 that is now used as a reference over here as it is supposed to be so good. The note was that the outcome was in  contrast with what individual members found to be the case with  that screen. I  am guessing gthe collaborators did some tests in  the field near their home and found less satisfying results. Also there was a notion   of jamming ventilators inside artifically aspirated screens. Sadly: in both cases as far as I can remember none of those remarks were elaborated but I  got the impression that the setting in Algeria was done with extreme radiation. From what I gathered there erre clear differences between lower and higher radiation situations per screen.  I live at 52 degrees north, quite different than 30 degrees in a desert.

What I am trying to say is that they hinted the Davis did not do so well under less extreme circumstances, which  are probably the ones most of us in Europe and northern USA/Canada live in. You can counter by saying that the most troublesome soiotuation still are those when we do get a lot of radiation.

Annyways back to the Meteoshield Pro: regardless of our preferences and our "needs"  based on where we measure, it needs to be determined what causes what in my view. Helical shape vs black inside...What is it. I have not found anything meaningful here. I won't promise I will do some work on it next year in order to give an indication. I might. But I am quite busy and have  many other hobbies so. But who knows.

The Barani setup is interesting because they do everything according to WMO standards. It is why I tried the lacklustre Peetbros sustem because for some parametres it did  the same.
« Last Edit: August 20, 2020, 09:46:40 AM by Jorginho »

Offline mauro63

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Re: Barani pro passive shield
« Reply #454 on: August 20, 2020, 09:51:46 AM »
Mauro, I do agree with both things of course. Getting rid of radiation errors should be the goal. But it is a very difficult and complicated matter. And there is no good or bad choice for amateurs here. Very few are so lucky to have a farmer nearby providing grassland to setup your system out in the open free of charge like I did. In fact I have several farmers in my neighbourhood. So to me it is essential since I have the same surroundings to come as close as possible to the KNMI as this is my reference. I cannot compare to cities surely not when radiation plays a big role. When you are however measuring things in the cities it becomes a lottery and I think money permitting your would do well to eradicate as much of radiative and other "errors" if you want to measure as correct as possible.

When we look into thestudy  done in Algeria in 2008 there was a small, but significant note on the Davis 7714 that is now used as a reference as it is supposed to be so good. The note was that the outcome was in  contrast with what individual members found to be the case with  that station. Also there was a notion   of jamming ventilators inside artifically aspirated screens. Sadly: in both cases as far as I can remember none of those remarks were elaborated but I  got the impression that the setting in Algeria was done with extreme radiation. From what I gathered there erre clear differences between lower and higher radiation situations per screen.  I live at 52 degrees north, quite different than 30 degrees in a desert.

What I am trying to say is that they hinted the Davis did not do so well under less extreme circumstances, which  are probably the ones most of us in Europe and northern USA/Canada live in. You can counter by saying that the most troublesome soiotuation still are those when we do get a lot of radiation.

Annyways back to the Meteoshield Pro: regardless of our preferences and our "needs"  based on where we measure, it needs to be determined what causes what in my view. Helical shape vs black inside...What is it. I have not found anything meaningful here. I won't promise I will do some work on it next year in order to give an indication. I might. But I am quite busy and have  many other hobbies so. But who knows.

The Barani setup is interesting because they do everything according to WMO standards. It is why I tried the lacklustre Peetbros sustem because for some parametres it did  the same.

Well Jorginho, I agree and is the same for me, I'm very busy with my job, and with a lot of cooperations with some weather equipment companies  ;)
about the highlighted part, I think could be a mix of aspects, the helical design improve the internal airflow, and the internal airflow is, in a passive solar radiation shield, the most important aspect to obtain a low time constant, a time constant enough low that does not mortify the sensor time constant.
I'm not talking about solar radiation, this is another aspect, and the internal airflow is only a help in this case, not the solution.
About the internal black paint, many other solar radiation shields use the same choice, simply painting the internal chamber, have you ever seen the inside of a Meteoshield Pro?

Mauro


Offline Jorginho

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Re: Barani pro passive shield
« Reply #455 on: August 20, 2020, 10:06:40 AM »
Not in reallife, but I did so on pcitures. Jan Barani showcased them and I saw the pictures. But not in detail. Is there something special/peculiar about them? Thx!

Offline mauro63

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Re: Barani pro passive shield
« Reply #456 on: August 20, 2020, 10:16:39 AM »
Not in reallife, but I did so on pcitures. Jan Barani showcased them and I saw the pictures. But not in detail. Is there something special/peculiar about them? Thx!

as you can see, but I think this is not easy from the public images, the internal layout is absolutely different from a traditional solar radiation shield, even and even more, precisely in the black internal parts, which are not integral with the external ones and follow the helicoidal also inside
if you want to send me your email privately I will see to give you some material and explain to you what we can do to solve your doubts  ;)

Mauro

Offline Jorginho

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Re: Barani pro passive shield
« Reply #457 on: August 20, 2020, 11:16:28 AM »
I understand that, which is why I added that I just saw the pics. I understand I could never judge based on pics. I can't even with the material in hand because I do not have any  knowledge on the subject of how air flows in such a station. Otoh: I think if someone has a bold claim, which  jan  has, he needs to come with very solid proof as how the principle works. I am surely not saying he doesnot have it nor am I suspiscious, I am and will remain critical until solid proof about the function is available. That can be seen  apart from its performance in the field. It could be the best )non-aspirated) screen ever regardless of how it achieves that performance.

Offline mauro63

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Re: Barani pro passive shield
« Reply #458 on: August 20, 2020, 11:33:06 AM »
I understand that, which is why I added that I just saw the pics. I understand I could never judge based on pics. I can't even with the material in hand because I do not have any  knowledge on the subject of how air flows in such a station. Otoh: I think if someone has a bold claim, which  jan  has, he needs to come with very solid proof as how the principle works. I am surely not saying he doesnot have it nor am I suspiscious, I am and will remain critical until solid proof about the function is available. That can be seen  apart from its performance in the field. It could be the best )non-aspirated) screen ever regardless of how it achieves that performance.


I'm sorry, I don't know what can I do more than this.

The Meteoshield Pro design is protected by international patent, and probably there's no intention to give deeper information
tests, made by simple users and Metrological Institutes, can confirm the performances, nobody of them is interested to have the technical explanation about how Meteoshield Pro can do this.

Your request is absolutely coherent, but I cannot help you with this.

In the most cases, every sport passionate man is happy to know if an athlete runs 100 meters in 8 seconds, but most people don't care how they perform their training phases, but this is not for you

this is taken from an official confidential document, I will not mention the source or which brands the letters in the table correspond to, these are professional screens known worldwide

 [ You are not allowed to view attachments ]

Mauro

Offline Jorginho

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I disagree.
« Reply #459 on: August 20, 2020, 11:54:49 AM »
First of all this is not directed to you, Mauro, because I never asked you for any help yet you are doing indeed all you can and I appreciate it a lot which I do with everyone else replying  here to me. It is what this what makes communities like these a very nice place to be. i always feel that my apparant very critical look and rigidity (I don't believe any claim until proof is there) somehow makes the atmosphere less nice. It seems I cannot help myself. I am simply used to question claims in cases where I take interest in.

To take your "100m sprint in  8 s" example: Someone  runs the 100 m in 8 s and it is measured without any doubt. Fine. A new world record. The person continues to say that some special but rather expensive food made him run that fast. Now surely people want to see proof for that before investing in that particular food, I would. So that is to me what I am asking here: sure it can be cooler, but is the design or is the paint the reason or a mix of both and then by how much does each  component contribute.

Thanks for the condidential report. I have to add that I am amazed why (I suppose) scientific reports should remain confidential but that is of course not up to you. For most people again it suffices that the screen works well. For some others like me, who are very curious, it is not enough. I have a tendency to always want to know how something works. Sorry...

Thx again Mauro for your time and effort!
« Last Edit: August 21, 2020, 07:19:47 AM by Jorginho »

Offline mauro63

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Re: I disagree.
« Reply #460 on: August 20, 2020, 12:01:18 PM »
First of all this is not directed to you, Mauro because I never asked you for any help yet you are doing indeed all you can and I appreciate it a lot. As I do with everyone else replying  here to me and others. It is what this what makes communities like these a very nice place to be. i always feel that my apparant very critical look and rigidity (I don't believe any claim until proof is there) somehow makes the atmosphere less nice. It seems I cannot help myself. I am simply used to question claims in cases where I take interest in.

To take your 100m sprint in  8 s example: Somewalsk 8 s and it is measured. Fine. A new world record., No doubt. The person continues to say that some special but rather expensive food made him walk that fast. Now surely people want to see proof for that before investing in that particular food, I would.

Thanks for the condidential report. I have to add that I am amazed why (I suppose) scientific reports should remain confidential but that is of course not up to you. For most people again it suffices that the screen works well. For some others like me, who are very curious, it is not enough. I have a tendency to always want to know how something works. Sorry...

Thx again Mauro for your time and effort!

Absolutely no problem,
this is one of the best forums ever, both for technical content and for the high respect and mutual esteem in every discussion.
Also, in this case, we are bringing only different information and views, absolutely obvious that this is the case.

thanks to you for the kind exchange of views
Mauro

Offline hmderek

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Re: Barani pro passive shield
« Reply #461 on: September 15, 2020, 10:18:58 AM »
Hot day here in September, insane how big the difference is between the standard Davis, 7714 and Barani Meteo Shield:
 [ You are not allowed to view attachments ]

Offline ivano

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Re: Barani pro passive shield
« Reply #462 on: September 15, 2020, 10:34:18 AM »
Hot day here in September, insane how big the difference is between the standard Davis, 7714 and Barani Meteo Shield:
 [ You are not allowed to view attachments ]
actually, the distance between davis7714 and met pro seems exaggerated, the sensor inside is the classic box? or are they probe sensors? a photo of the installation? I'm sorry you know I'm an enthusiast who makes many comparisons between professional screens [tup]
1)2 gw1000
2)hp2551
3)ws80
4)ws68
5)2wh32 EP
6)3 wh31 EP
7)2 meteoschield pro
8)schermo lastem
9) davis 7714
10)wh40
11)schermo solare Rotronic

Offline ConligWX

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Re: Barani pro passive shield
« Reply #463 on: September 15, 2020, 11:18:43 AM »
actually, the distance between davis7714 and met pro seems exaggerated, the sensor inside is the classic box? or are they probe sensors? a photo of the installation? I'm sorry you know I'm an enthusiast who makes many comparisons between professional screens [tup]

Perhaps some dimensions of the shields could also be given. area of mass etc. From photos I have seen on the page before, the Barani may have less area to soak up the heat. which will allow for lower temperature readings.  One of the reasons I fitted a Daytime FARS on my Davis ISS just to help out temps on a hot day - though there is very few of them in Northern Ireland!
Regards Simon
Davis Vantage Pro2 Plus Daytime FARS WeatherLink Live CumulusMX Saratoga Templates


Offline Jorginho

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Very hot: 33,9 C over here in the Vaisala
« Reply #464 on: September 15, 2020, 11:24:07 AM »
Hot day here in September, insane how big the difference is between the standard Davis, 7714 and Barani Meteo Shield:
 [ You are not allowed to view attachments ]
actually, the distance between davis7714 and met pro seems exaggerated, the sensor inside is the classic box? or are they probe sensors? a photo of the installation? I'm sorry you know I'm an enthusiast who makes many comparisons between professional screens [tup]

Your max of 30,1 C (I think I found it on wunderground) is in inline with 30,6 C as Tx for Hoogeveen KNMI station.

33,9 C is in fact a provincial record for Middelburg Noordoost. Westdorpe KNMI went to 33,6 C. The previous record here in the countryside was 32,5 C in 2013 I think 5 september. I seriously hate heat so I am not really enjoying this all.

Nice to see the difference. Is your weatherstation sheltered from with (if so, to what degree?). Nice performance. If it is sheltered it seems to be a very nice way to measure in such a position and still be able to compare to KNMI stations! Thx for sharing!

Offline hmderek

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Re: Very hot: 33,9 C over here in the Vaisala
« Reply #465 on: September 15, 2020, 11:55:35 AM »
Your max of 30,1 C (I think I found it on wunderground) is in inline with 30,6 C as Tx for Hoogeveen KNMI station.

33,9 C is in fact a provincial record for Middelburg Noordoost. Westdorpe KNMI went to 33,6 C. The previous record here in the countryside was 32,5 C in 2013 I think 5 september. I seriously hate heat so I am not really enjoying this all.

Nice to see the difference. Is your weatherstation sheltered from with (if so, to what degree?). Nice performance. If it is sheltered it seems to be a very nice way to measure in such a position and still be able to compare to KNMI stations! Thx for sharing!

Pretty sure you got the right station on Wunderground. :-) I'm quite pleased with the max temps using the Meteoshield. I'm somewhere between 2 KNMI stations with max temps of 30,6 and 29,8.

My station is full sun all day up until around 16.30 around this time. I live out in the open, so mostly get wind if there is any. (Too many trees to get decent max winds though).

Graphs are available here: https://meteodrenthe.nl/#/grafieken
You can see the sensors inside the 7714 and standard shield drop sharply as soon as the station catches shade. Meteoshield probably slightly too, I guess that's to be expected.

As for the differences being exaggerated. It sure does feel that way, and especially the 7714 is disappointing, but maybe it wasn't designed with the SHT31 in mind.

This is the current setup:
 [ You are not allowed to view attachments ]
« Last Edit: September 15, 2020, 11:57:49 AM by hmderek »

Offline Jorginho

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Re: Barani pro passive shield
« Reply #466 on: September 15, 2020, 01:17:22 PM »
I just took off the sensorcap of my Davis, got rid of the medium in it and replaced it with something that is far more permeable for wind and the responsetime difference is night and day! And it is now in line with my TinyTag Plus datalogger with its "fastresponse probe". With the standard Davis sensor things went south whenever a quick change in temperature should have  been measured. Like today we had a seabreeze around 16h. The temperature just went down very fast as well as it went up swiftly when we reached the 34 C. The humidity sensor never goes beyond 97% which is typical for Davis SHT31 sensors....

Eelde KNMI didn't go further than 29,8 C....geez...That seems pretty cold, even  Leeuwarden went to 29,9 C.

The 7714 was made for the stainlessstell probe which cam with the Weatherwizard III and WMII. But there is no reason really why it should not function properly with the SHT31 Davis with sensorcap. Again: just exchange the material with something that allows air to flow better without it being open to droplets. I just used my wifes panty's which are tightly woven. I have  been doing since 2016 and everything is fine 4 yrs onwards.
« Last Edit: September 15, 2020, 01:29:37 PM by Jorginho »

Offline hmderek

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Re: Barani pro passive shield
« Reply #467 on: September 15, 2020, 01:35:17 PM »
The humidity sensor never goes beyond 97% which is typical for Davis SHT31 sensors....

A bit off topic, but I read that a lot. Oddly, I don't have that experience. I hit 99% frequently, even had 100% on August 4th last month.

Offline ivano

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Re: Barani pro passive shield
« Reply #468 on: September 15, 2020, 02:48:01 PM »
excellent location, I have a location similar to yours this  [ You are not allowed to view attachments ]  only instead of using sht31 I use WH32 / 31 with sht35 wave  [ You are not allowed to view attachments ]  on the roof I have this position instead  [ You are not allowed to view attachments ]  all with sensors WH31/32 sht35 , it seemed excessive to me the gap between meteshield pro and davis in the position on the ground, I have this distance between the pro and the davis  [ You are not allowed to view attachments ]  ,  [ You are not allowed to view attachments ]  however it is still in the test phase, one thing is certain, the meteoshield pro, has no rivals for the moment when it comes to passive screens ;)
1)2 gw1000
2)hp2551
3)ws80
4)ws68
5)2wh32 EP
6)3 wh31 EP
7)2 meteoschield pro
8)schermo lastem
9) davis 7714
10)wh40
11)schermo solare Rotronic

 

anything