Author Topic: Barani: too good to be true...  (Read 5178 times)

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Offline Jasper3012

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Re: Barani: too good to be true...
« Reply #50 on: May 07, 2024, 02:13:12 AM »
Sorry but youíve repeated the same narrative about 10 times now and posted the same graph over and over, it honestly seems like youíre going a bit over the top now. We understand the flaws and Iím sure Jan Barani has received the criticism aswell.

Offline Meteorology fan

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Re: Barani: too good to be true...
« Reply #51 on: May 07, 2024, 02:26:00 AM »
@Jasper3012 - Fellow tobyportugal further as you can see does not understand and does not see the problem. He is clinging to either the sensors or the way they are measured. Either he doesn't want to see, or he doesn't know how to check it and under what conditions product defects will be highlighted. Apparently, he has not read scientific studies that clearly describe such phenomena, which I was not the only one to cite in this topic.
« Last Edit: May 07, 2024, 02:28:29 AM by Arkadiusz_w »
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Offline Jasper3012

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Re: Barani: too good to be true...
« Reply #52 on: May 17, 2024, 03:09:43 AM »
Started a comparison of my own now, Barani MeteoShield vs Davis FARS 24/7. Both have the exact same SHT-35 sensor and sensor housing. First night was immediately a good test, namely a calm and clear night. Youíd expect the passive shield to have a slightly higher min on a night like that and indeed, FARS got 8.7C, Barani 9.0C. The reported min/max will be 1-min averaged min/max, not the instantaneous values.

Offline Dador

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Re: Barani: too good to be true...
« Reply #53 on: May 17, 2024, 03:41:30 AM »
@Jasper3012
If you have such terrain conditions, please pay attention to whether there is actually a big difference between the shields in the morning or evening sun, low above the horizon. If I may have a personal request, please also share the daily average temp data for both shields.
« Last Edit: May 17, 2024, 03:43:29 AM by Dador »

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Re: Barani: too good to be true...
« Reply #54 on: May 17, 2024, 03:56:02 AM »
Jasper3012 -  With me, the minimum values are generally comparable on SHT35 and calibrated PT1000. Differences are rarely greater than 0.1įC to Sensirion SHT35 in the minimums. Sometimes the maxima from the whole day differ up to 0.1/0.3 degrees to the PT1000. I have the filters completely removed on the SHT35 from the Ecowitt WH31EP/WH32EP for fast response time. I recommend you also do this and put in one cover and the other side by side without filters. Just be careful not to damage the probe and cables.

Here are some charts from this month, as I and my colleagues continue to do comparison tests with Apogee and Davis FARS 24H and Barani. Lately, however, there have been windy days and the advantages of vented are only in the morning and in the evening, when the wind is weak and heating is the greatest area of radiation shielding. So not in all conditions it will highlight to us.

In the next few weeks I will give further results of comparisons in a separate thread about Barani Gen III, as we are still waiting for hot summer days and little wind to highlight clearly the flaws in these conditions.

On a radiant night when there is no wind, the Davis FARS24H responds faster than the passive Barani Gen III. Sometimes it can be as fast as 0.5/1 degree if the drop is rapid and in windless conditions, and the air in the Barani stands still due to lack of wind. It can sometimes happen that the minimums are lower on FARS, because it catches a drop such that the passive shield misses in the absence of wind. I've seen this sort of thing in the winter at colleagues between Apogee and Barani and Davis FARS24H and Stevenson cages, among others.
« Last Edit: May 17, 2024, 04:08:38 AM by Arkadiusz_w »
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Offline tobyportugal

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Re: Barani: too good to be true...
« Reply #55 on: May 17, 2024, 10:35:04 AM »
Started a comparison of my own now, Barani MeteoShield vs Davis FARS 24/7. Both have the exact same SHT-35 sensor and sensor housing. First night was immediately a good test, namely a calm and clear night. Youíd expect the passive shield to have a slightly higher min on a night like that and indeed, FARS got 8.7C, Barani 9.0C. The reported min/max will be 1-min averaged min/max, not the instantaneous values.

Sorry, but you can't compare a sensor that's placed vertically in one and horizontally in the other. It's like trying to compare tyre wear between a rear-wheel drive car and a front-wheel drive car.
It's like those who put a SHT in an Apogee: it's absurd.
J'ai hate de rentrer au Portugal.... quel temps ici en Belgique  ;)

Offline tobyportugal

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Re: Barani: too good to be true...
« Reply #56 on: May 17, 2024, 10:39:48 AM »
https://www.wxforum.net/index.php?action=dlattach;topic=46657.0;attach=60142

 ](*,) ](*,) Do you make comparisons with this type of risky set-up? And we're supposed to believe your conclusions....

Offline Meteorology fan

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Re: Barani: too good to be true...
« Reply #57 on: May 17, 2024, 11:38:30 AM »
@tobyportugal I refer to the material regarding passive and active shielding:

https://www.youtube.com/watch?v=G9xdVQii_YY

In Apogee we place both SHT35 without filters and PT100 and PT1000 4-wire. Similarly, in Barani Gen III and Davis FARS24H. We know when these differences are.

We recommend you watch this material and then you will understand why the Barani passive shield in low wind conditions does not show the correct air temperature and we have seen this repeatedly, confirmed on a minimum of four and even six independent sensors in different shields. For us, the Barani Gen III cannot replace the meteorological screen Stevenson.

Take a look at the Apogee TS100 vs Davis FARS24H charts. These are new charts, because we have some of these Apogee in Poland with different sensors. Similarly, Davis FARS24H.

At my place, I removed the Barani Meteoshield Pro III from the main measurement on the WH32EP Ecowitt. It remained as a backup measurement on WH31EP duplicated with a PT1000 resistance sensor with logger. Other colleagues in the country did the same. The ram serves as a comparison of whether the windmill works properly most of the time, even though it is hooked up to a permanent backup power supply, has batteries inside and solar on the Davis FARS24H. The main reason why I did this is to overestimate the temperature when the wind blows weakly and the sun shines from the side into the covers and frequent temperature errors. In winter, showing a positive temperature when we have a negative temperature is unacceptable esteemed colleague and it was not uncommon in low wind conditions in the cold half of the year in Poland.

When it comes to Apogee TS100 vs Davis FARS24H comparisons. You can see how they are close to each other most of the time and show analogous or strongly similar temperatures. We checked the graphs with the PT1000 and PT100 and it looks the same.
« Last Edit: May 17, 2024, 11:56:25 AM by Arkadiusz_w »
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Offline Jasper3012

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Re: Barani: too good to be true...
« Reply #58 on: May 17, 2024, 12:46:44 PM »
Started a comparison of my own now, Barani MeteoShield vs Davis FARS 24/7. Both have the exact same SHT-35 sensor and sensor housing. First night was immediately a good test, namely a calm and clear night. Youíd expect the passive shield to have a slightly higher min on a night like that and indeed, FARS got 8.7C, Barani 9.0C. The reported min/max will be 1-min averaged min/max, not the instantaneous values.

Sorry, but you can't compare a sensor that's placed vertically in one and horizontally in the other. It's like trying to compare tyre wear between a rear-wheel drive car and a front-wheel drive car.
It's like those who put a SHT in an Apogee: it's absurd.
J'ai hate de rentrer au Portugal.... quel temps ici en Belgique  ;)

And why would that be the case? If youíre going to go down that road, you might aswell stop comparing altogether, since youíll always find something to pick onÖ

Offline Jasper3012

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Re: Barani: too good to be true...
« Reply #59 on: May 17, 2024, 12:50:03 PM »
Stats for first day:
Barani: 9.0C min 18.3C max 13.5C avg
FARS: 8.7C min 18.6C max 13.5C avg

A day with sunny spells and light to moderate wind (10-15 km/h).

Offline Meteorology fan

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Re: Barani: too good to be true...
« Reply #60 on: May 17, 2024, 01:17:32 PM »
Here are mine today and you can compare the maximum and minimum values measured in the Barani Meteoshield Pro III vs Davis FARS24H. You can see that the maximum temperature was about 0.2įC higher on the vented vs. passive. However, a strong wind was blowing, with gusts up to 30-50 km/h. We noticed that in strong winds, ventilated shields such as the Apogee TS100 and Davis FARS24H can show a few tenths higher values and the temperature changes faster on them than on passive shields.

Average daily air temperature on Davis FARS 24H 15.2įC
Average daily air temperature on Barani Meteoshield Pro III 15įC

The data in this situation comes from both the PT1000 4-wire and Sensirion SHT35 sensors. The loggers and resistance probes are correctly synchronized in time. Reading with Logsoft software, which I downloaded from the following site. The software allows you to create graphs, tabulate data and as files for external programs.

https://termoprodukt.co.uk/soft

Today the flaws of the Barani Meteoshield Gen III passive shield didn't work out due to strong and gusty winds for most of the day.
« Last Edit: May 17, 2024, 01:19:33 PM by Arkadiusz_w »
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Offline Jasper3012

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Re: Barani: too good to be true...
« Reply #61 on: May 17, 2024, 01:29:31 PM »
Winds only gusted to like 20-25 km/h at most here and yet still 0.3C cooler on the Barani. Quite an impressive performance, Iíd say. Time will tell how they compare long term in the Belgian climate.

Offline Meteorology fan

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Re: Barani: too good to be true...
« Reply #62 on: May 17, 2024, 01:49:57 PM »
This higher temperature by a few tenths may have been due to the faster response of the shield from FARS. We observe the same phenomenon on Apogee, among others, on windy days relative to passive shields. This changes when the wind noticeably weakens and then it is cooler in the active ones. The number of such days in the Belgian climate may be less noticeable than in Poland, but they can happen. In general, however, maxima and minima will agree on Barani Gen III and Davis FARS24H or there will be these readings close to each other most of the time. It is worth adding to this comparison if possible PT100 or PT1000 with loggers and time synchronization. These are more accurate and responsive than the SHT35 from Sensirion.
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Offline Jasper3012

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Re: Barani: too good to be true...
« Reply #63 on: May 17, 2024, 01:59:28 PM »
Iím not so sure on the theory that the higher temps on the FARS are due to a faster response time tbh, a wind speed of 10-15 km/h should be enough to reduce the difference in response time between the passive and active shield to near zero. I think itís more likely that the wind disrupts the airflow generated by the fan and you end up with a greater error than with natural ventilation.

Offline tobyportugal

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Re: Barani: too good to be true...
« Reply #64 on: May 17, 2024, 02:15:02 PM »
Started a comparison of my own now, Barani MeteoShield vs Davis FARS 24/7. Both have the exact same SHT-35 sensor and sensor housing. First night was immediately a good test, namely a calm and clear night. Youíd expect the passive shield to have a slightly higher min on a night like that and indeed, FARS got 8.7C, Barani 9.0C. The reported min/max will be 1-min averaged min/max, not the instantaneous values.

Sorry, but you can't compare a sensor that's placed vertically in one and horizontally in the other. It's like trying to compare tyre wear between a rear-wheel drive car and a front-wheel drive car.
It's like those who put a SHT in an Apogee: it's absurd.
J'ai hate de rentrer au Portugal.... quel temps ici en Belgique  ;)

It's simple: Davis shelters (rectangular, remember) are designed for their PCBs.
If you haven't mounted your SHT35 STRICTLY in the same place as the SHT31-LSS (height, width, length) and on a PCB, your measurements will never be correct.
The Davis PCB is important because the air doesn't circulate away from the diaphragm. A "free" SHT will be influenced by the air circulating between its opposite side and the top of the enclosure.
Try mounting a Davis SHT in a shelter (Barani, Comet, Metspec, etc.) and you will never get a correct value because the Davis PCB becomes an obstacle. Otherwise, a SHT without a PCB in a Davis will not be in its design definition.
Take a shelter (brand of your choice) and change the height of the sensor by 5mm and you will get differences. A Comet F8004 is very instructive for understanding the vital importance of mounting in the reliability of measurements.
Now, everyone can do as they please. As far as I'm concerned, comparing without taking great care with the mounting makes no sense. There will be no stability, you'll see differences between shelters depending on weather events and not on the design of the shelters.
« Last Edit: May 17, 2024, 02:22:34 PM by tobyportugal »

Offline Jasper3012

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Re: Barani: too good to be true...
« Reply #65 on: May 17, 2024, 02:30:52 PM »
The FARS sensor chamber isnít rectangular, itís a cilinder on the inside and with no flat surface. You canít mount a PCB on it.

Offline tobyportugal

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Re: Barani: too good to be true...
« Reply #66 on: May 17, 2024, 02:47:44 PM »
The FARS sensor chamber isnít rectangular, itís a cilinder on the inside and with no flat surface. You canít mount a PCB on it.

for the rectangle, you're right, I had 7714 in my memory. But there's a PCB.
see manuel
https://www.meteo-shopping.com/fr/station-meteo-sans-fil/638-station-meteo-vantage-pro-2-sans-fil-avec-ventilation-active.html

Offline Meteorology fan

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Re: Barani: too good to be true...
« Reply #67 on: May 17, 2024, 03:22:43 PM »
@Jasper3012

It may make sense that stronger winds disrupt the airflow in the active shield, hence there may be slightly higher values in the maximum temperature. Daily maxima are generally not higher on the ventilated 0.2/0.3 deg.C compared to the passive Barani Gen III when we have stronger wind. Instead, I think it's worth owning and comparing active and passive, having measurement redundancies on analog sensors. In my city, the MWC, or urban heat island, has an impact. It happens that with the morning and evening winds here are weak and FARS brings quite an improvement in measured temperature and humidity compared to the passive counterpart. Below is the construction design of the FARS24H shields from the inside.
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Offline Jasper3012

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Re: Barani: too good to be true...
« Reply #68 on: May 17, 2024, 04:17:31 PM »
Think Iím going to cut down on that mounting board a bit so the mass is reduced and I can place the sensor down in a vertical manner.

Offline CW2274

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Re: Barani: too good to be true...
« Reply #69 on: May 17, 2024, 05:50:08 PM »
It may make sense that stronger winds disrupt the airflow in the active shield, hence there may be slightly higher values in the maximum temperature.
Long time member here, ValentineWeather, brought up this exact concern years ago about the VP2 24hr shield. Without any side ventilation, stronger wind could potentially overwhelm the stock motor and cause stagnation within the sensor chamber. I agreed with his assessment and convinced me to move to a stronger case fan, which I did. Now, that possibility is moot. 

Offline Jasper3012

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Re: Barani: too good to be true...
« Reply #70 on: May 18, 2024, 02:22:12 AM »
What ventilator are you using now? Are there stronger ventilators that fit in nicely in the housing of the Davis stock ventilator? I might consider buying a stronger one aswell, if I notice maxes being too high during sunny and windy days. Iíll definitely have to look for another power source for during the winter aswell, as I live at 51N and on average thereís only 1-2 h of (low angle) sunshine a day, probably not enough to keep the FARS going throughout the entire season.

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Re: Barani: too good to be true...
« Reply #71 on: May 18, 2024, 02:39:43 AM »
@Jasper3012 In autumn and winter, battery power is not enough at Davis FARS24H. I had the same thing and colleagues in Poland also experienced it, as we have a lot of Davis FARS 24H in the country. Stopping the windmill will cause a delay in the casing and heavily averages the measurement. We created an alternative power supply. Pictures below, I used 40 m of cable, gave a USB cable to the house and connected to a weak phone charger. In addition, I connected the 5V charger to a WIFI smart socket with a programmer to turn on the power at any time, or at a specific time in the programmer.

If you completely deprive the Davis FARS24 of batteries, then the windmill runs at maximum speed all the time, which may not be beneficial in all conditions and may affect the life of the FARS. On the other hand, with batteries and such a connection as below, the speed is regulated depending on the sunshine. You can also optionally use voltage regulators, as we also experimented with this in Poland. If you want, I will show you more about it.

I, at my place, have one battery in Davis FARS24, a constant power supply of 40 m and power from the solar. The passive shield is used to compare whether the operation of the windmill is not disturbed and whether the measurements coincide on analog sensors. In my opinion and colleagues Davis FARS24H is better than Barani Gen III most of the time, but requires periodic maintenance, additional alternative power supply. So it's not maintenance-free, but it does sound higher measurement accuracy in low wind conditions than the Barani and other companies' passive shield. You can put any SHT35/SHT31 sensor with probe and PT100/PT1000 which we did. The purchase was made from the auction below, we made the mounts in-house.

https://www.wetterladen.de/bestrahlungsschutzschild-6831-mit-24-stunden-aktivbelueftung?c=1140
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Offline Jasper3012

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Re: Barani: too good to be true...
« Reply #72 on: May 18, 2024, 02:57:27 AM »
Maybe a dumb question, but canít you just replace the batteries every few weeks in winter and keep it going that way? My station is in a field, hundreds of metres away from any houses, so I canít really get a constant power supply. Iíll probably need a larger solar panel and more sets of batteries.

Offline CW2274

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Re: Barani: too good to be true...
« Reply #73 on: May 18, 2024, 03:06:36 AM »
Maybe a dumb question, but canít you just replace the batteries every few weeks in winter and keep it going that way? My station is in a field, hundreds of metres away from any houses, so I canít really get a constant power supply. Iíll probably need a larger solar panel and more sets of batteries.
Then my case fan solution is worthless to you. It's 12vdc and requires power from the mains unless you fabricate something else as you allude to. The battery solution is doable, but certainly not easy, at least comparatively speaking of just powering the fan from an extension cord.

Offline Meteorology fan

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Re: Barani: too good to be true...
« Reply #74 on: May 18, 2024, 03:07:02 AM »
@Jasper3012 The solar panel may not be efficient enough in winter. The option with battery replacement is not the worst, but it may raise the risk of interrupting the measurement with active ventilation. Optionally, use a large battery (something like a car battery) and hook up in a similar way as I did in the photos to DC power if you have several hundred meters to the buildings. I have 40 meters from the building in the garden pulled a long cable for permanent power supply.
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Barani Meteoshield Pro II, III, Davis FARS 24H