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Weather Station Hardware => Barani Design Weather Stations and Accessories => Topic started by: jerryg on August 18, 2018, 09:35:15 AM
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I wanted to start a new thread about the pro and standard Barani Designs passive shield and how it works in the backyard of normal pws, any professional studies and comparisons can be found on the Barani home page. And to start i finally got a morning with no wind and no clouds on the horizon to block the sun so i could see how the shields i have in use compared when the sun was hitting the plates at maximum exposure. The standard shield gets some morning shade from my tower and it and the fars which is in full sun ran the same temp. The pro ran about .4 to .5 higher until the wind picked up and then it was running the same as the others. I just want to add that i came up with the top plate idea about adding shade to the shield and passed it along to Valentine, so my bad if it upset the purist in the group. I am always trying different things to improve my readings and will keep doing so. I got the idea of the top plate from looking at the high dollar shields they use on the climate research stations which spec at less than .05F added to temp. The shield is a 3 tube design but has a single large plate that shades the tubes in the heat of the day and i thought if it's good enough for them i would try it and it works. So don't blame Valentine for the idea we both like to try out various things, some work some don't. We both have some sensor housing coming that we will be trying out. So any of you who are thinking about trying a better passive shield then hang it there for further reports. Hey remember the cotton region shelter was the best at the time then someone decided to add the second set of louvers and that became the best then someone said why white inside lets paint it black and absorb radiation inside the shield and that became the best and along came the gill plate design and again the best until the fan was added now that is the standard, so finding better ways of housing sensors is always ongoing =D>
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Awesome Jerry.
If I get any new info I'll drop in.
Was up until 1am last night setting up my test shields. Think my neighbors wonder what I'm smoking. :lol:
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Ha, i have that over you, where i live out in the country i have no one to know i am crazy with all the stuff i have out on the weather tower :lol: . Just a funny note i had a guy going down the road who stopped an asked what i was doing with all the bee hives, i was trying out several cotton regional shelters :lol:.
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With a little wind seeing the pro do better today, Only by 1/2 degree.
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Need to do a little updating, finally some weather that lets me check things out with low wind speed and sunny. It looks like the oversize plate on top of the pro and standard shield are doing a pretty good job. The pro has been running around a degree lower than the fars and the standard shield has been around half degree lower. When a cloud comes over the fars temp drops pretty quickly down to the pro temp and so does the standard. The pro only drops a few tenths with cloud cover and when the cloud moves by the pro goes up a few tenths and the fars goes back up to the 1 degree higher which shows the fars temp is being affected by the solar heating of the sun on the shield which is shown in the specs of the shield. I think later in the year when the solar energy is a lot lower the plate won't be necessary and the sun angle will probably be too low for an overhead plate to do any good. With the plate atop the two shields when the wind was calm or low the temp of the pro got withing half a degree of the fars on the low side and the standard went up to the fars temp.
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Jerry I possibly see why on your end you see the Davis FARS running so much higher than I do. My FARS is only .4 or so higher vs the Pro with a breeze continuously. You see over a full degree F.
You are using the stock fan correct? I use a more powerful AC fan. Back Pressure from the wind is hampering the stock fan.
This is exactly what the WMO study said! The Davis FARS ran warmer with wind... Bingo \:D/
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...the fars goes back up to the 1 degree higher which shows the fars temp is being affected by the solar heating of the sun on the shield which is shown in the specs of the shield...
I would argue that all Davis specs are suspect after the move they've pulled with humidity. In any event, Davis is assuming you're using their fan and power section that produces just under 1 m/s flow in the daytime. If memory serves you're running the fan at 3V off a wall wart during the day, but I'm not sure how much that increases the fan rate. Any idea?
According to the research I've read, 1 m/s is the line below which significant errors occur. The pro/reference gear is all above 2 m/s (much of it 3 m/s or higher) to avoid under aspiration.
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This is exactly what the WMO study said! The Davis FARS ran warmer with wind... Bingo \:D/
Except that he said his winds were low.
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This is exactly what the WMO study said! The Davis FARS ran warmer with wind... Bingo \:D/
Except that he said his winds were low.
Low to Jerry may be what I'm seeing today from basically 0 mph first few days to around 6-8 mph at surface feels like a hurricane. :lol:
Just with that amount of wind my Pro shield is running lower around .3F over AC fars, I'll post a graph later this evening. We do have storms coming so maybe earlier actually.
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Check this out, with just a little wind even the AC FARS runs higher. Solar is much worse as Jerry has reported. I thought something was wrong but now I see what he's talking about. These Davis FARS are hampered by wind.
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I sent these graphs to Barani explaining this is even with higher powered fan not stock.
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I am running 2.3 volts on the fan, near the same as the solar panel, i have it set to cut off at night to avoid messing up my sensor with too much moisture input. My shield is a 14 inch round tray with a 1 inch lip that was dark gray so no paint on bottom and painted white on top. I have been watching the temp of the fars vary as much as 1 degree between sunshine and when a cloud comes over. If you forget the temp. part of this i look at it this way the fars has a fan that dies or sticks, batteries to run at night if using solar, gets real dirty shield and filter, needs cleaning and if using solar batteries may not run all night if not getting good charge during day time because of clouds or amount of sun time available in the winter and higher latitudes. Now the Barani unique design keeps shield and sensor filter cleaner, less cleaning time, no problem with sensor getting overly wet, response seems better, the stuff the shield is made from is slick so water doesn't remain on the plates and dirt and bugs slide off, it says lol. A lot of this has to be seen in the long term and hope it all comes to pass.
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Need to do a little updating, finally some weather that lets me check things out with low wind speed and sunny. It looks like the oversize plate on top of the pro and standard shield are doing a pretty good job. The pro has been running around a degree lower than the fars and the standard shield has been around half degree lower. When a cloud comes over the fars temp drops pretty quickly down to the pro temp and so does the standard. The pro only drops a few tenths with cloud cover and when the cloud moves by the pro goes up a few tenths and the fars goes back up to the 1 degree higher which shows the fars temp is being affected by the solar heating of the sun on the shield which is shown in the specs of the shield. I think later in the year when the solar energy is a lot lower the plate won't be necessary and the sun angle will probably be too low for an overhead plate to do any good. With the plate atop the two shields when the wind was calm or low the temp of the pro got withing half a degree of the fars on the low side and the standard went up to the fars temp.
I earlier (in other post) asked about that circular (pizza) plate above the Barani Pro passive shield because previously I did something similar for my LaCrosse WS-8610 wireless weather unit...only I used a circular piece of perforated sheet metal from Home Depot. Did this mod in an attempt to mitigate the "heat-of-the-day" temperature HUMP that occurred with the wimpy stock OEM LaCrosse solar "shield." Was able to reduce solar effects from 3-4ºF down to 1-2ºF using the perforated metal 'shield' above the LaCrosse unit same as you've done. I used the perforated sheet metal because it was less prone to "flying" in high-wind situations. It was flat, but I believe having it rounded or domed downward would probably work better.
What are your thoughts?
Some of the "professional" passive radiation shields have the bowl design up top for extra protection against higher solar angles. This one is from Comet.
(http://i1283.photobucket.com/albums/a541/hwcorder/weather-shelter_big_zpshkbl6yv0.jpg) (http://s1283.photobucket.com/user/hwcorder/media/weather-shelter_big_zpshkbl6yv0.jpg.html)
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Nice I'll start looking for something like that.
The ASOS has a huge bowl on top also, I'm guessing in the 14" diameter range.
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Check this out, with just a little wind even the AC FARS runs higher. Solar is much worse as Jerry has reported. I thought something was wrong but now I see what he's talking about. These Davis FARS are hampered by wind.
I see that once solar insolence reaches 500 W/m2 the temperature differential in the two shields is constant, regardless of wind speed.
For example, between 10-11AM winds are relatively low. Around 11AM wind speed rapidly doubles but the differential remains the same (and by my eye may even be a tad smaller). That's despite insolation continuing to rise which should create additional solar radiation errors assuming the FARS sensor is inadequately ventilated compared to the Barani sensor.
Maybe once winds get "high" the relationship is clear, but unfortunately the WMO didn't define what constitutes "high wind speed" for the Davis FARS.
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Check this out, with just a little wind even the AC FARS runs higher. Solar is much worse as Jerry has reported. I thought something was wrong but now I see what he's talking about. These Davis FARS are hampered by wind.
I see that once solar insolence reaches 500 W/m2 the temperature differential in the two shields is constant, regardless of wind speed.
assuming the FARS sensor is inadequately ventilated compared to the Barani sensor.
This is crazy talk as far as I'm concerned. I'm not arguing that the FARS is reading slightly higher but blaming it on a breeze is nonsense in my eyes.
Someone please explain how a breeze going to stagnate air in the chamber, scientifically?
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Check this out, with just a little wind even the AC FARS runs higher. Solar is much worse as Jerry has reported. I thought something was wrong but now I see what he's talking about. These Davis FARS are hampered by wind.
I see that once solar insolence reaches 500 W/m2 the temperature differential in the two shields is constant, regardless of wind speed.
assuming the FARS sensor is inadequately ventilated compared to the Barani sensor.
This is crazy talk as far as I'm concerned. I'm not arguing that the FARS is reading slightly higher but blaming it on a breeze is nonsense in my eyes.
Someone please explain how a breeze going to stagnate air in the chamber, scientifically?
Pressure perturbations caused by airflow around the fars could disrupt the constant airflow through the sensor chamber. Makes sense as this would probably overcome a weaker fan like a stock one first. Now turbo charge the fan like you have and it would take a stronger wind to cause any disruption.
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Check this out, with just a little wind even the AC FARS runs higher. Solar is much worse as Jerry has reported. I thought something was wrong but now I see what he's talking about. These Davis FARS are hampered by wind.
I see that once solar insolence reaches 500 W/m2 the temperature differential in the two shields is constant, regardless of wind speed.
assuming the FARS sensor is inadequately ventilated compared to the Barani sensor.
This is crazy talk as far as I'm concerned. I'm not arguing that the FARS is reading slightly higher but blaming it on a breeze is nonsense in my eyes.
Someone please explain how a breeze going to stagnate air in the chamber, scientifically?
I was only attempting to show that even if you conceded the idea that "high winds" were the culprit for the discrepancy between the two shields, there appears to be no easily identifiable relationship between increased wind speed and shield temperature differential according to the graphs Randy just posted.
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Check this out, with just a little wind even the AC FARS runs higher. Solar is much worse as Jerry has reported. I thought something was wrong but now I see what he's talking about. These Davis FARS are hampered by wind.
I see that once solar insolence reaches 500 W/m2 the temperature differential in the two shields is constant, regardless of wind speed.
assuming the FARS sensor is inadequately ventilated compared to the Barani sensor.
This is crazy talk as far as I'm concerned. I'm not arguing that the FARS is reading slightly higher but blaming it on a breeze is nonsense in my eyes.
Someone please explain how a breeze going to stagnate air in the chamber, scientifically?
Pressure purterbations caused by airflow around the fars could disrupt the airflow through the sensor chamber.
Get that. The problem is that would be a momentary instance, an anomaly, not a continuous condition as is being reported.
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Check this out, with just a little wind even the AC FARS runs higher. Solar is much worse as Jerry has reported. I thought something was wrong but now I see what he's talking about. These Davis FARS are hampered by wind.
I see that once solar insolence reaches 500 W/m2 the temperature differential in the two shields is constant, regardless of wind speed.
assuming the FARS sensor is inadequately ventilated compared to the Barani sensor.
This is crazy talk as far as I'm concerned. I'm not arguing that the FARS is reading slightly higher but blaming it on a breeze is nonsense in my eyes.
Someone please explain how a breeze going to stagnate air in the chamber, scientifically?
I was only attempting to show that even if you conceded the idea that "high winds" were the culprit for the discrepancy between the two shields, there appears to be no easily identifiable relationship between increased wind speed and shield temperature differential according to the graphs Randy just posted.
I wasn't inferring that you were making crazy talk, if you thought I was, the contrary, I agree with you. Until there's empirical evidence to the contrary saying the breeze is responsible, I'll continue on my doubtful ways.
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I have a question on this, i am in no way very knowledgeable about air flow, but i read in a thread that the fars was designed with an air intake that narrows down and causes an increase in air speed that is 2.4 times faster than if it was just an open tube. Wouldn't that help keep the wind from causing a disruption and warmer temps?
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Maybe this can be applied to the idea of a fan being overpowered by wind inside the sensor chamber. But I'm no engineer just an ex operator.
Just an :idea:
If, if the wind was at a constant velocity, I mean whereas an anomalous condition became the constant that defeated the purpose of the fan and/or chamber, I suppose I could get in line, but even this is pure conjecture. The wind is far to dynamic for this to occur IMHO.
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Check this out, with just a little wind even the AC FARS runs higher. Solar is much worse as Jerry has reported. I thought something was wrong but now I see what he's talking about. These Davis FARS are hampered by wind.
I see that once solar insolence reaches 500 W/m2 the temperature differential in the two shields is constant, regardless of wind speed.
assuming the FARS sensor is inadequately ventilated compared to the Barani sensor.
This is crazy talk as far as I'm concerned. I'm not arguing that the FARS is reading slightly higher but blaming it on a breeze is nonsense in my eyes.
Someone please explain how a breeze going to stagnate air in the chamber, scientifically?
Pressure purterbations caused by airflow around the fars could disrupt the airflow through the sensor chamber.
Get that. The problem is that would be a momentary instance, an anomaly, not a continuous condition as is being reported.
We would have to know the wind speed where this occurs. Theoretically as long as the windspeed stays above that air could remain disrupted. Only way to really verify this would be to set this up in a wind tunnel with multiple pressure and airflow sensors.
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I have a question on this, i am in no way very knowledgeable about air flow, but i read in a thread that the fars was designed with an air intake that narrows down and causes an increase in air speed that is 2.4 times faster than if it was just an open tube. Wouldn't that help keep the wind from causing a disruption and warmer temps?
Can't answer that except that the 24hr FARS sensor chamber cylinder is the same diameter top to bottom.
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Check this out, with just a little wind even the AC FARS runs higher. Solar is much worse as Jerry has reported. I thought something was wrong but now I see what he's talking about. These Davis FARS are hampered by wind.
I see that once solar insolence reaches 500 W/m2 the temperature differential in the two shields is constant, regardless of wind speed.
assuming the FARS sensor is inadequately ventilated compared to the Barani sensor.
This is crazy talk as far as I'm concerned. I'm not arguing that the FARS is reading slightly higher but blaming it on a breeze is nonsense in my eyes.
Someone please explain how a breeze going to stagnate air in the chamber, scientifically?
Pressure purterbations caused by airflow around the fars could disrupt the airflow through the sensor chamber.
Get that. The problem is that would be a momentary instance, an anomaly, not a continuous condition as is being reported.
We would have to know the wind speed where this occurs. Theoretically as long as the windspeed stays above that air could remain disrupted. Only way to really verify this would be to set this up in a wind tunnel with multiple pressure and airflow sensors.
Then this supposed problem would have been identified loooong ago, as keeping the air AOA the critical velocity (whatever that would be) occurs surely countless times every day. It's just a tad easier to have the wind above a certain point than it is to be at a constant, constantly.
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Yes the chamber is the same but at the bottom where the air enters it is restricted by that disk shaped piece that i think shields the chamber from reflected heat and forms the vintura , spelled wrong, effect. That was how it was described in the patent application.
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Yes the chamber is the same but at the bottom where the air enters it is restricted by that disk shaped piece that i think shields the chamber from reflected heat and forms the vintura , spelled wrong, effect. That was how it was described in the patent application.
Yes, see what you're saying.
With that, and my common sense (for what it's worth), I am completely unconvinced that wind causes a high bias temp, certainly for any kind of continuity.
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I wonder how they determined it was the wind and not some other anomaly. The wind speed varies quite a bit so like you said i would think it would be in spurts and not a lot at that.
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I would like to see more test showing the same results. Like others I a little dubious over their conclusion that the Davis fars runs too cool in light wind to calm conditions. It's difficult to get a thermometer to read on the cool side during the day.
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Thanks to Jerry & Randy, I pulled the trigger and bought the pro shield. I guess I’m now a part of the club. Lol
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Great i think you will be happy with it.
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Both shields ended almost same .3 difference high temperature, few clouds in afternoon. The Fars was warmer until afternoon about .4F. Wind is at 2.5' above sensor level or 8'.
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Pro vs Standard, The 7714 was also 90.3 for a high so tied the PRO. Standard was warmest of 4 shields at 90.9°. Max differential between the 4 shields .9 with a breeze.
Even though the max temps were close in reality the Pro ran cooler for larger portion of day over all shields. Wasn't until almost 4:30 pm when FARS was slightly better or the same.
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Are these graphs of the same shields? Appears to me that in the morning graph (top graph above running from about midnight to 2pm) there's about a 1 degree differential, but in the later graph (whose time scale somewhat overlaps the first) the two shields are neck and neck.
If anything, the morning graph should appear more compressed since the image is not as tall and it has a y-axis (temperature) with a larger scale (5 more degrees). But in fact, it's the graph showing more separation between shields.
My guess would be that the first graph shows a different shield comparison. The Barani standard vs pro?
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Comparing the time-equivalent TEMP versus insolation numbers should provide a hint as to why things are happening as they are.
It would be helpful for you to quote whom you're addressing. I'm going to assume this was in response to my post immediately above yours.
Look more closely. The two graphs overlap in time somewhat (approx 10a - 2pm). At no point in the 2nd graph is there the separation we see in the 1st graph during the same period. This has nothing to do with insolation as that's a constant if you compare the same shields in the same time period.
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Are these graphs of the same shields? Appears to me that in the morning graph (top graph above running from midnight to noon) there's about a 1 degree differential, but in the later graph (whose time scale somewhat overlaps the first) the two shields are neck and neck.
If anything, the morning graph should appear more compressed since the image is not as tall and it has a y-axis (temperature) with a larger scale (5 more degrees). But in fact, it's the graph showing more separation between shields.
My guess would be that the first graph shows a different shield comparison. The Barani standard vs pro?
Yes the top graph scale is less and only went until 2:30, being less condensed so better view. The second is full day much more condensed not as clear on tracking.
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Are these graphs of the same shields? Appears to me that in the morning graph (top graph above running from midnight to noon) there's about a 1 degree differential, but in the later graph (whose time scale somewhat overlaps the first) the two shields are neck and neck.
If anything, the morning graph should appear more compressed since the image is not as tall and it has a y-axis (temperature) with a larger scale (5 more degrees). But in fact, it's the graph showing more separation between shields.
My guess would be that the first graph shows a different shield comparison. The Barani standard vs pro?
Yes the top graph scale is less and only went until 2:30, being less condensed so better view. The second is full day much more condensed not as clear on tracking.
Both graphs depict about 14 hours in time scale and 30-35 degrees in temperature scale. So if there's a 1 degree difference that appears nearly constantly in one graph, it should also appear in the 2nd graph since they overlap during the period of differential (which begins around 10AM). Their scale is the roughly same, just time shifted somewhat.
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I wonder also now looking at it. I guess it's possible the first graph was different shield like standard by mistake. I moved the transmitters around the fars previously was on standard frequency so switched them and may have grabbed wrong shield.
Also it was only .4 difference not 1°as depicted on graph.
Regardless the Pro ran below the Fars on average around .4 until late afternoon just wasn't as big of difference on first graph.
I was convinced even sent the graph to Barini I'll now need to send them email on this.
Apologize that happened everyone.
I'll leave the transmitter status at bottom of graph for now on so doesn't happen again .
TX-1 is Pro, Tx-3 Fars, TX-6 Standard
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I wonder also now looking at it. I guess it's possible the first graph was different shield like standard by mistake. I moved the transmitters around the fars previously was on standard frequency so switched them and may have grabbed wrong shield.
Also it was only .4 difference not 1°as depicted on graph.
Regardless the Pro ran below the Fars on average around .4 until late afternoon just wasn't as big of difference on first graph.
I was convinced even sent the graph to Barini I'll now need to send them email on this.
Apologize that happened everyone.
I'll leave the transmitter status at bottom of graph for now on so doesn't happen again .
TX-1 is Pro, Tx-3 Fars, TX-6 Standard
It's an easy mistake to make. I know because I've done stuff like that too. In the end all that matters is that we know that the later graph (~10a - midnight) is correct and can draw conclusions from that. Appreciate the clarification, Randy. :-)
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A little better look of Pro vs Fars yesterday. Notice left TX status at bottom alone because of my screw up and lesson learned. :oops:
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A little better look of Pro vs Fars yesterday. Notice left TX status at bottom alone because of my screw up and lesson learned. :oops:
The slight separation between 4:30 - 5:00PM looks to correspond to a temporary slow down in wind speeds.
Wondering if the reason the Pro runs underneath for the majority of the daytime hours is due to heat radiation from the fan in the FARS. I'm splitting hairs here, of course, as we're inside the Davis spec for temp (+/- 0.5F). Just spitballing....
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A little better look of Pro vs Fars yesterday. Notice left TX status at bottom alone because of my screw up and lesson learned. :oops:
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Yes, on that plot, it's easy to see when the solar peak occurred (≈3:43 PM) and the temp differences "switched" places: 'TX1 < TX3-FARS' switched to 'TX3-FARS > TX1'.
Glad you can see that. I switched data logger back to 5 minutes those times are too close at 1 minute. Plus the data logger captures high and low in 5 minute block.
Barani asked for 1 minute not realizing high and low were captured.
openvista
I may switch to Stock FARS today if I get more energy.
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If it was the fan, why are we only seeing it during higher insolation?
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If it was the fan, why are we only seeing it during higher insolation?
Good point.
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If it was the fan, why are we only seeing it during higher insolation?
My SWAG (Stupid Wild Ass Guess) is that it's the *latent* heat that's been *accumulated/stored/retained* within the radiation shield material that is slightly warming the cooler incoming air the fan sucks in.
Could be.
Randy, how old is the FARS shield? That plastic decays with time. When I replaced a top plate recently, the old one had grey discolorations all over it and it was yellowing pretty badly too. I'm guessing older plastic performs worse than newer plastic.
Again, we're splitting hairs here, so no worries either way.
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A little better look of Pro vs Fars yesterday. Notice left TX status at bottom alone because of my screw up and lesson learned. :oops:
Wondering if the reason the Pro runs underneath for the majority of the daytime hours is due to heat radiation from the fan in the FARS.
No. That's why the fan is located above, not below the sensor. What little heat the motor does generate is blown out top by it's own fan.
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A little better look of Pro vs Fars yesterday. Notice left TX status at bottom alone because of my screw up and lesson learned. :oops:
Wondering if the reason the Pro runs underneath for the majority of the daytime hours is due to heat radiation from the fan in the FARS.
No. That's why the fan is located above, not below the sensor. What little heat the motor does generates is blow out top by it's own fan.
Yeah agree I still want to test the solar fan for awhile.
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A little better look of Pro vs Fars yesterday. Notice left TX status at bottom alone because of my screw up and lesson learned. :oops:
Wondering if the reason the Pro runs underneath for the majority of the daytime hours is due to heat radiation from the fan in the FARS.
No. That's why the fan is located above, not below the sensor. What little heat the motor does generates is blow out top by it's own fan.
Yeah agree I still want to test the solar fan for awhile.
8-)
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It will be interesting to see your results, i tried that some time ago and the results were not very good. I thought the fan might help with airflow problems with light winds but i think all it did was draw the hot air in off the plates and up the temp quite a bit. The plates are most effective when they shade the fars tube and allow the air being drawn up the tubes to remove any heat from them so the center chamber stays at ambient air temp.
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Well switched the Davis FARS to stock and within 2 minutes fan died (Batteries I'm sure dead) ](*,) and no sun for recharge so this will end any comparison test until tomorrow.
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Well switched the Davis FARS to stock and within 2 minutes fan died
:lol:
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:oops:
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high and low for today, windy today average wind 7 mph average gust 20 mph pro shield with top plate min 76.8/max 96.6 fars min 77.1/max 97.2 standard shield without top plate min 76.7/max 96.6 Nothing like wind to equalize things.
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Just as a somewhat related aside, I've had several clear days/nights here recently. My 7714 passive shield and 7755 active shield perform indistinguishably, even in light 10m winds (1-3mph). Highs & lows are within a few tenths. One wrinkle has been some very thin smoke high up in the atmosphere, not enough to reduce visibility and undetectable most of the time except on satellite. According to the CRN station about 25 miles away in Chatham, today we reached a max radiation value of 748 Wh/m2 (yesterday: 797, Friday: 734).
Again, the 7714 only performs this well on my property when raised to 20ft. Down low it can run up to 4+ degrees warmer due to insufficient breeze. Just FYI, it's on a south-facing eave mount just over 6ft above the ridge line of my garage.
In other words, in moderate insolation conditions, at least, the passive shield performs identically to the FARS with even the slightest of breezes, and the FARS performs well despite what is apparently a significant siting disadvantage.
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In other words, the passive shield performs identically to the FARS with even the slightest of breezes, and the FARS performs well despite what is apparently a significant siting disadvantage.
Granted, semantics, but I think your FARS is not at a disadvantage, it's sat where it's suppose to be. The passive shield has the advantage because it's sat where it's not suppose to be.
However, point taken, good passive with a breeze = good data.
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In other words, the passive shield performs identically to the FARS with even the slightest of breezes, and the FARS performs well despite what is apparently a significant siting disadvantage.
Granted, semantics, but I think your FARS is not at a disadvantage, it's sat where it's suppose to be. The passive shield has the advantage because it's sat where it's not suppose to be.
However, point taken, good passive with a breeze = good data.
The FARS is sheltered from winds from the NE to the S (about 150 degrees) and too close to reflected heat sources (pavement mostly). You put a passive shield there and it goes berserk. Cooling lake breezes comes from the E and the passive can't reach them down at 2m. But up high....
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Update todays min/max pro shield 75.8/96.6 fars 75.8/97.8 no standard shield today was moving it around. Wind was light in am then moderate in the afternoon to windy with seabreeze coming in. Sky was partly cloudy today.
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Update min/max for today pro 75.1/100.0 fars 75.4/100.9 standard 75.3/100.3 winds today were calm to light all morning then light in the afternoon and breezy with seabreeze around 4 pm and sky was basically sunny a few fluffy clouds at times.
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Heck i am not declaring anything just showing results in my location, i am not a scientist or anything else just a weather nut and i don't have access to anything but what i see. You can get better stuff from the makers home page with studies, my report is just general back yard stuff and take it or leave it.
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I'll post some graphs later for PRO/FARS comparison, waiting for the peak temps to end.
I'm at a much less windy area vs Jerry so my data does look different.
I did install my second PRO at remote site today. Data is here: Went in service at 15:19- 68°.
https://mesowest.utah.edu/cgi-bin/droman/meso_base_dyn.cgi?stn=E7498
This is the intown station for compare and airport 1.3 mi.
Town: https://mesowest.utah.edu/cgi-bin/droman/meso_base_dyn.cgi?stn=E3958&unit=0&timetype=LOCAL/
Airport: https://mesowest.utah.edu/cgi-bin/droman/meso_base_dyn.cgi?stn=KVTN&unit=0&timetype=LOCAL/
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Wow two pros, i am impressed lol. Makes me feel less like a nut :lol: . I don't know if i would travel around to set it up at a remote site, still jealous of those temps, man after a 100 degrees today i felt much cooler just looking at your temps and thinking how great it would be to have to put on a jacket to go outside :-(
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Hazy day, few thin clouds, wind on light side but not dead still either.
We have 90's in forecast this weekend again.
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Hazy day, few thin clouds, wind on light side but not dead still either.
We have 90's in forecast this weekend again.
Randy, is the FARS still running the AC fan?
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Hazy day, few thin clouds, wind on light side but not dead still either.
We have 90's in forecast this weekend again.
Randy, is the FARS still running the AC fan?
I switched to stock solar unit.
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I corrected the wind graph. Earlier was TX2 which is 30'.
Correct 8' is with FARS unit on TX3.
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It's our first breezy sunny day with average wind speeds 5-6mph and gusts to 15mph. I'm seeing a pretty consistent pattern: the 7714 is about a degree cooler than the FARS.
Highs so far (2:30PM EDT):
76.2 (7714)
77.4 (FARS)
It's been a partly cloudy all day. Max solar radiation 795 Wh/m2 (in Chatham 25 mi away; the entire Midwest is under a dome of high pressure).
Lows are always within a tenth or two as both shields converge at night.
Yesterday, during a windy, cloudy day I was seeing about 0.5F difference most of the day with the passive running cooler.
It seems on calm, sunny days sensor overheating can dominate all other factors primarily on passive shields. On windy, sunny days the differences must hinge on shield material and configuration rather than air movement. I'm still wondering if replacing my FARS with new plastic would yield a better outcome.
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76.2 (7714)
77.4 (FARS)
On windy, sunny days the differences must hinge on shield material and configuration rather than air movement.
How about the fact that your 7714 is 20' in the air, isn't it?
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I'm seeing the pro superior with a 3-5 mph wind at shield level, all other shields including FARS,
range is (.3) to (.9)F difference. Field level anemometer moved to transmitter #6 standard.
Snap shot.
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I’ll wait for your graphs. You’re back to the stock fan, correct?
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All stock on Davis FARS. Clouds rolled in as you can see on solar, plus sun soon gets behind trees which messes up test because some shields are in sun others not,,,, making one shield look better than other. I switched 8' wind to Standard #6 to clean up area so I could mow between shields and not move cables. ;)
These are the best shields so for clean comparison only including best two.
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I'm seeing the pro superior with a 3-5 mph wind at shield level, all other shields including FARS,
range is (.3) to (.9)F difference. Field level anemometer moved to transmitter #6 standard.
Snap shot.
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Noticed with the pro that the DP is sometimes 1° cooler than the others
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These are the best shields so for clean comparison only including best two.
Granted, early, but are you gleaning that the stock fan is under performing compared to the a/c fan?
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I'm seeing the pro superior with a 3-5 mph wind at shield level, all other shields including FARS,
range is (.3) to (.9)F difference. Field level anemometer moved to transmitter #6 standard.
Snap shot.
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Noticed with the pro that the DP is sometimes 1° cooler than the others
Could be.... The difference I see in temperature with this little amount of wind is very small.
Jerry see's larger difference as winds get up. Still haven't had a real windy day to test.
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76.2 (7714)
77.4 (FARS)
On windy, sunny days the differences must hinge on shield material and configuration rather than air movement.
How about the fact that your 7714 is 20' in the air, isn't it?
True. This could very well go back to siting.
Reflected/emitted radiation is more of a factor during the day. That's felt more near ground level. More specifically, there's a fair amount of pavement closer, both horizontally and vertically, to the FARS (within 25ft in two directions) and it's more sheltered down there so the heat can pool for a bit longer before being replaced by cooler air.
The issue today was felt most when radiation was strongest. Comparing the average temperatures spanning the 2 hours straddling solar noon (12:52PM - 2:52PM local time), I see a 0.81F difference with the 7714 coolest.
In the hour preceding the high temp (4:40PM - 5:40PM), the avg difference was 0.23F with the 7714 still cooler even though it was 0.1F higher for the daily max than the FARS.
Given that I'm not seeing large variances in highs and lows, I'd still defer to the 2m FARS shield.
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Unscientific update sky partly cloudy winds light, calm in am picking up to 7 to 10 mph. pro 72.8/99.4 fars 72.8/100.4 standard 73.2/100.6
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Unscientific update sky partly cloudy winds light, calm in am picking up to 7 to 10 mph. pro 72.8/99.4 fars 72.8/100.4 standard 73.2/100.6
Noticed that the other stations near you (RAWS & Airports) reported 100-101°
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These are the best shields so for clean comparison only including best two.
Granted, early, but are you gleaning that the stock fan is under performing compared to the a/c fan?
Yes, no, maybe.....
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These are the best shields so for clean comparison only including best two.
Granted, early, but are you gleaning that the stock fan is under performing compared to the a/c fan?
Yes, no, maybe.....
'
The wind was up today is the difference I see. I also moved the Fars shield for better sun exposure.
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Did I read somewhere on this forum that the USGS uses the Standard MeteoShield?
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Did I read somewhere on this forum that the USGS uses the Standard MeteoShield?
It was one of those. Jerry told me they sold the first batch of stock. I was thinking USGA but may have been USGS both make sense. Not sure if it was just standard shield however.
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Well I bought another transmitter and got it set up today. Running two 75's now one in the Meteoshield Pro (main station) and another in a Davis FARS (Extra Temp Station) with stock fan. Didn't get to do a lot of scientific comparing today but from what I could eyeball the Meteo Pro generally ran cooler. Will have to look at the highs when I get off work late tonight. Like the rest of you I really wish Davis would start supporting temp in tenths of a degree with their extra temp stations. Dont really see how this would be difficult.
Ill also start supplying some graphs for comparison.
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Well I bought another transmitter and got it set up today. Running two 75's now one in the Meteoshield Pro (main station) and another in a Davis FARS (Extra Temp Station) with stock fan. Didn't get to do a lot of scientific comparing today but from what I could eyeball the Meteo Pro generally ran cooler. Will have to look at the highs when I get off work late tonight. Like the rest of you I really wish Davis would start supporting temp in tenths of a degree with their extra temp stations. Dont really see how this would be difficult.
Ill also start supplying some graphs for comparison.
You can get tenths with a meteobridge/weatherbridge pro if you transmit to it directly from the ISS.
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update partly cloudy skies and light winds in am to breezy in afternoon with seabreeze. Pro 72.6/98.3 fars 72.6/99.2 standard 72.8/98.7
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I'm using envoy8x even though old and never updated software it does the job, really couldn't live without. Supports 8 pro stations or combo of soil/leaf.
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Well I bought another transmitter and got it set up today. Running two 75's now one in the Meteoshield Pro (main station) and another in a Davis FARS (Extra Temp Station) with stock fan. Didn't get to do a lot of scientific comparing today but from what I could eyeball the Meteo Pro generally ran cooler. Will have to look at the highs when I get off work late tonight. Like the rest of you I really wish Davis would start supporting temp in tenths of a degree with their extra temp stations. Dont really see how this would be difficult.
Ill also start supplying some graphs for comparison.
You can get tenths with a meteobridge/weatherbridge pro if you transmit to it directly from the ISS.
I'm using envoy8x even though old and never updated software it does the job, really couldn't live without. Supports 8 pro stations or combo of soil/leaf.
Yeah I just don't know if I want to put any more money into more hardware right now. I guess I'll just have to make due with the decreased resolution for now.
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Well I bought another transmitter and got it set up today. Running two 75's now one in the Meteoshield Pro (main station) and another in a Davis FARS (Extra Temp Station) with stock fan. Didn't get to do a lot of scientific comparing today but from what I could eyeball the Meteo Pro generally ran cooler. Will have to look at the highs when I get off work late tonight. Like the rest of you I really wish Davis would start supporting temp in tenths of a degree with their extra temp stations. Dont really see how this would be difficult.
Ill also start supplying some graphs for comparison.
You can get tenths with a meteobridge/weatherbridge pro if you transmit to it directly from the ISS.
I'm using envoy8x even though old and never updated software it does the job, really couldn't live without. Supports 8 pro stations or combo of soil/leaf.
Yeah I just don't know if I want to put any more money into more hardware right now. I guess I'll just have to make due with the decreased resolution for now.
I hear ya. You guys are banging out these Barani shields left and right and they don’t come cheap.
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Yesterday was a breezy totally sunny day with sustained winds running between 5-15mph with a few peaks around 20mph. Only had a partial day with both shields running. The high on both FARS and PRO was 80 degrees.
Today should be similar although winds should be a little less. I will give another update after the highs have been reached and supply some graphs as well although I'm kind of a newbie at messing around with these graphs on weather display.
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Wind was sporadic yesterday for me. My FARS was .9 cooler on peak. When wind is up the Pro does slightly better.
I think once the wind stops FARS is pulling cooler air off the grass is what's going on. I went outside when it was 90° and putting hand on lawn it's cooler than air temperature for sure. Put that same fars shield over hot sand results would be different even on calm days.
I think bare ground would be better indication and grass causes artificial cooling. One of the reasons I'm running 1-2 degrees under airport. Nothing but sand and cactus everywhere mixed with prairie grass.
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Another day of no wind. ](*,)
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Another day of no wind. ](*,)
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The Pro shield looks really good to me. But I do find it interesting that the DP on the pro shield is 1° lower than the other shields.
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Wind was sporadic yesterday for me. My FARS was .9 cooler on peak. When wind is up the Pro does slightly better.
I think once the wind stops FARS is pulling cooler air off the grass is what's going on. I went outside when it was 90° and putting hand on lawn it's cooler than air temperature for sure. Put that same fars shield over hot sand results would be different even on calm days.
I think bare ground would be better indication and grass causes artificial cooling. One of the reasons I'm running 1-2 degrees under airport. Nothing but sand and cactus everywhere mixed with prairie grass.
The air heats from the ground up during the day. The ground should feel cooler with it touching directly to your skin versus your layer of bodyheat in open air. 70F water feels a lot cooler to your skin than 70F air.
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Just a quick clarification, if I have an ISS transmitter 2016 or later and an sht75 I need to add the 0.9 degree offset correct? Just trying to make sure numbers are right.
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Yes add +.9F with new transmitter and old sensors. Subtract .9F with SHT31 and older pre Jan 1 2016 transmitter.
If transmitter was made after Jan 2016 and SHT31 no change needed.
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But he's asking about the 75, does that need it too? :???:
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Thanks ValentineWeather! I'm going to go ahead and post todays graph for the last 24hrs since I will probably not get a chance the rest of this evening and I think we have hit our highs for the day. The FARS and MeteoPro have been running pretty darn close but I think over all the Meteo is running just a little cooler. Did not see the need to add solar to this as we have had another day for full sunshine. I also pulled out an old my original VP2 console this afternoon. Its getting data from the FARS station so at least I can report highs and lows to the tenths if a degree. Both recorded lows of 57F this morning. MeteoPro peaked at 80.3 @ 4:46pm while the FARS peaked at 80.9 @ 3:16pm.
(https://beta-static.photobucket.com/images/a541/hwcorder/s0/f834ee3b-205c-41a9-93ac-f9069bd70c80-original.png?width=1920&height=1080&fit=bounds) (https://beta.photobucket.com/u/hwcorder/p/f834ee3b-205c-41a9-93ac-f9069bd70c80)
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But he's asking about the 75, does that need it too? :???:
Yes they are included with the older sensors. SHT11,15,75.
The 75 is soon to be phased out unfortunately and is best sensor of the 3.
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Better get mine out too, past peak. Prep football tonight, cousin's gs plays. FARS cooler by .4F.
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But he's asking about the 75, does that need it too? :???:
Yes they are included with the older sensors. SHT11,15,75.
The 75 is soon to be phased out unfortunately and is best sensor of the 3.
Okay, cobwebs cleared, thanks.
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FARS cooler by .4F.
Is this one still the stock fan?
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Update skies clear light winds until afternoon with seabreeze pro 98.1/73.1 fars 98.9/73.0 standard with new sht15 sensor 98.5/73.3
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I do need to add when looking at my graph my instruments are in the shade until about 1130am.
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FARS cooler by .4F.
Is this one still the stock fan?
Yes it's located over grass 5', pulling air from bottom. ;)
It took me awhile to realize why the airport ASOS also pulling air from bottom with much stronger suction over mainly sand runs 1-2° warmer. #-o
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FARS cooler by .4F.
Is this one still the stock fan?
Yes it's located over grass 5', pulling air from bottom. ;)
It took me awhile to realize why the airport ASOS also pulling air from bottom with much stronger suction over mainly sand runs 1-2° warmer. #-o
Certainly makes sense.
I know you're doing a boat load of comparisons, but if you get bored (right....:roll:), I'd like to see you do stock fan vs a/c. The sunnier, hotter, and calmer, the better. :-)
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FARS cooler by .4F.
Is this one still the stock fan?
Yes it's located over grass 5', pulling air from bottom. ;)
It took me awhile to realize why the airport ASOS also pulling air from bottom with much stronger suction over mainly sand runs 1-2° warmer. #-o
Certainly makes sense.
I know you're doing a boat load of comparisons, but if you get bored (right....:roll:), I'd like to see you do stock fan vs a/c. The sunnier, hotter, and calmer, the better. :-)
I've done that for years over grass very little if any difference. Maybe over hot sand you might see a slight increase but it may be opposite what you think.
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FARS cooler by .4F.
Is this one still the stock fan?
Yes it's located over grass 5', pulling air from bottom. ;)
It took me awhile to realize why the airport ASOS also pulling air from bottom with much stronger suction over mainly sand runs 1-2° warmer. #-o
Certainly makes sense.
I know you're doing a boat load of comparisons, but if you get bored (right....:roll:), I'd like to see you do stock fan vs a/c. The sunnier, hotter, and calmer, the better. :-)
I've done that for years over grass very little if any difference. Maybe over hot sand you might see a slight increase but it may be opposite what you think.
Yeah, I guess you have. Regardless, I would never consider going back to stock, just curious.
Back to your regularly scheduled program...
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Doing something different today. Almost zero wind again ](*,) at 30'. Its 11am with sunny but some smoke haze from all the fires. Haze scheduled to clear out after 1pm they are saying so maybe winds will pick up.
Anyway I moved the FARS to the one area of bare ground on my 1/4 acre of paradise (just a patch) but still surrounded by lush grass all directions. to see if fars drawing cooler rising air vs horizontal air sample the passive shields are sampling pans out. This patch of bare ground may not be significant enough to make much difference but will see.
Fars currently .4f cooler than pro.
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ValentineWeather:
What software do you use to create the graphs you are sharing?
Does it read from a database or do you have to extract from one that has all the values in it before sending it to the graphing routine?
Dale
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hwcorder:
Same question for you as ValentineWeather:
To be able to graph stuff on demand rather than continuously all values is a nice possibility.
If you and he have documented what you're using, I apologize for asking again.
Your shade fills and other tweaks seem to indicate a different graphing routine than what he uses.
Dale
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ValentineWeather:
What software do you use to create the graphs you are sharing?
Does it read from a database or do you have to extract from one that has all the values in it before sending it to the graphing routine?
Dale
I'm using the WTU software that comes with Envoy8x. It saves everything to database either windows or Mysql, it has a export function into Excel where I make the graphs.
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Doing something different today. Almost zero wind again ](*,) at 30'. Its 11am with sunny but some smoke haze from all the fires. Haze scheduled to clear out after 1pm they are saying so maybe winds will pick up.
Anyway I moved the FARS to the one area of bare ground on my 1/4 acre of paradise (just a patch) but still surrounded by lush grass all directions. to see if fars drawing cooler rising air vs horizontal air sample the passive shields are sampling pans out. This patch of bare ground may not be significant enough to make much difference but will see.
Fars currently .4f cooler than pro.
None of that makes sense to me, but I already posted my thoughts on it. Even if the immediate skin sfc was a little cool under the shade of the grass blades, you're going to be running superadiabatic from the grass blades to 2m range. If you're measuring over full sun, 1ft AGL should not be cooler than 6ft AGL.
Try mounting your FARS at 1-2ft over the grass and see what happens. Heck, maybe I'll be wrong. ;)
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hwcorder:
Same question for you as ValentineWeather:
To be able to graph stuff on demand rather than continuously all values is a nice possibility.
If you and he have documented what you're using, I apologize for asking again.
Your shade fills and other tweaks seem to indicate a different graphing routine than what he uses.
Dale
I use the advanced graphs function in Weather Display.
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Here is my graph for today. I added solar since I had a few clouds. Winds were very light today with some periods of calm of near calm conditions. I noticed during these times the Meteo Pro did run a little warmer 0.5-1.0+F than the FARS with a larger spike visible right before I posted this. Once the winds picked it cam back down. Thats where I think FARS really shines, when things get dead still. Highs and Lows, Meteo Pro 60.1 / 86.6 FARS 60.2 / 85.2.
(https://beta-static.photobucket.com/images/a541/hwcorder/s0/bdac5c92-8ee8-4583-838f-6705982d46d8-original.png?width=1920&height=1080&fit=bounds) (https://beta.photobucket.com/u/hwcorder/p/bdac5c92-8ee8-4583-838f-6705982d46d8)
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Update skies partly cloudy winds light in am to breezy in afternoon with seabreeaze pro 73.0/97.2 fars 72,9/98.0 standard 72.8/98.2
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Well i made a change this am i changed out the Davis fars with the RM Young fars which is the industry standard shield everyone compares to. See specs here http://www.youngusa.com/products/2/16.html Now will see how pro does against a professional shield.
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Jerry,
thanks for the variety of tests and units.
I'm interested in how the RMYoung does, so run it awhile and if you can on sunny vs. cloudy days.
thanks for doing the work. Nice unit, I followed the link, and seems as good as it can get. I wonder if their fans burn out as fast as the Davis ones do?
Did Campbell Scientific make a funny looking thing that had a big bulge on one end and a horizontal white tube with a 45 degree angle cut on one end? The 'Big Boys' have the bucks to do the engineering and research, so I'm wondering how well they work compared to the amateur and low end pro stuff we use, and you are the only one who I recall has tested this so please graph and publish and discuss, just so we know. Dale
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Well i don't know how to graph but i can tell you how i see it performing, and it will be a while to get a good read but i have already seen something that i long suspected about the Davis fars in high humidity areas and that is in the am the fars readings barely changed with the sun coming up and took about an hour to start showing the correct temp and humidity readings compared to the pro or standard shield. The rmy fars and the pro are tracking pretty well with the temp and humidity of the fars immediately starting to change, no lag time at all. Right now there is no wind and the fars and pro both show 80.8 degrees. I need to add that i took the sht75 out of the Davis and it is now in the rmy so should be pretty good comparison to earlier readings.
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Well i don't know how to graph but i can tell you how i see it performing, and it will be a while to get a good read but i have already seen something that i long suspected about the Davis fars in high humidity areas and that is in the am the fars readings barely changed with the sun coming up and took about an hour to start showing the correct temp and humidity readings compared to the pro or standard shield. The rmy fars and the pro are tracking pretty well with the temp and humidity of the fars immediately starting to change, no lag time at all. Right now there is no wind and the fars and pro both show 80.8 degrees. I need to add that i took the sht75 out of the Davis and it is now in the rmy so should be pretty good comparison to earlier readings.
This will clear up for sure if the Davis FARS wasn't working correctly. I suspect something was wrong especially since you mentioned the humidity lag on the davis unit. You wouldn't expect to see it unless the fan's not working, turning the shield into a bad passive unit.
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In response to the fan, it rates at 80,000 hrs of run time. It is a squirrel cage type fan. Suck a golf ball through a garden hose :lol:
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It is a squirrel cage type fan. Suck a golf ball through a garden hose :lol:
Exactly. Put a decent fan in your VP2 and I'll bet that lag will go bye-bye.
As a matter of fact, I just took my new 40CFM out and replaced it with my newer 60CFM fan just so I can hear it working out in the desert, the 40 was too quiet. Works beautifully!
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Here is todays graph.
Todays Hi and Lo.
Met Pro 90.6 / 64.3
FARS 89.6 / 64.5
(https://beta-static.photobucket.com/images/a541/hwcorder/s0/9c60cb2f-4b74-4d67-bb88-3517fade0ee7-original.jpg?width=1920&height=1080&fit=bounds) (https://beta.photobucket.com/u/hwcorder/p/9c60cb2f-4b74-4d67-bb88-3517fade0ee7)
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Today, notice what happened when what breeze we had stopped during peak heat of day. Bad timing, I was higher than airport with pro which never happens.
Pro: 97.9-56.4
Fars: 96.4-56.4
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Today, notice what happened when what breeze we had stopped during peak heat of day. Bad timing, I was higher than airport with pro which never happens.
Pro: 97.9-56.4
Fars: 96.4-56.4
Bad timing? Is this not exactly what you're trying to accomplish, to see if the Pro can handle a no wind, full sun scenario as well as a good FARS?
The only person on here as far as I've noticed that the Pro is always lower than the FARS is "jerryg", and he lives where a breeze is almost always a constant, and that's with the :roll: stock fan.
I think it's becoming quite obvious that the Pro is truly an exceptional passive shield, but it's not a FARS, certainly not a good one.
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Okay changed Pro shield around because of limited room inside sensor chamber, now have just the 1-sensor SHT75 inside.
With the 75 DIY longer sensor cable I'm able to raise sensor from shield lower section to middle of sensor chamber allowing the airflow design to work as intended. Being on very bottom may not take advantage of shields helical design.
If using 31 they do make the 30' SHT31 where you can position shield where you want (away from ISS).
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Here is look after changes made with pro shield as of 2pm central full sun no clouds currently. Not bad with light winds averaging under 2 mph sometimes dead still. Late afternoon sun still coming.
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Keep in mind we’re quickly approaching an equinoctial sun angle too. I wonder if these would perform similarly at the summer solstice.
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Looks good today considering sub 2 mph average speed. Not sure if changes made any difference but looks good.
Fars was .5 cooler on high temperature but with <2 mph wind the Pro is working well.
I watched carefully today and the pro just responds quicker IMO and why spikes may be more prevalent. The 7714 is as slow as a tortoise at responding to any changes sometimes a 5 minute delay or no response at all. I pointed out a few with red dots you can see the larger spikes and deeper dips.
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I watched carefully today and the pro just responds quicker IMO and why spikes may be more prevalent.
Makes sense. As I see it, the Pro is responding more so like a FARS than the 7714 simply due to it's seemingly better design in lighter wind conditions.
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Looks good today considering sub 2 mph average speed. Not sure if changes made any difference but looks good.
Fars was .5 cooler on high temperature but with <2 mph wind the Pro is working well.
I watched carefully today and the pro just responds quicker IMO and why spikes may be more prevalent. The 7714 is as slow as a tortoise at responding to any changes sometimes a 5 minute delay or no response at all. I pointed out a few with red dots you can see the larger spikes and deeper dips.
Also keep in mind that there is shield lag and sensor lag. The 75 responds much, much faster than the Davis mounted 31.
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Looks good today considering sub 2 mph average speed. Not sure if changes made any difference but looks good.
Fars was .5 cooler on high temperature but with <2 mph wind the Pro is working well.
I watched carefully today and the pro just responds quicker IMO and why spikes may be more prevalent. The 7714 is as slow as a tortoise at responding to any changes sometimes a 5 minute delay or no response at all. I pointed out a few with red dots you can see the larger spikes and deeper dips.
Also keep in mind that there is shield lag and sensor lag. The 75 responds much, much faster than the Davis mounted 31.
Ah! maybe that's what I'm seeing. If I remember someone said it's the only one designed as meteorological sensor. I know there is a new version coming out but with the I2C which won't work. So I guess we need to stock up...
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Looks good today considering sub 2 mph average speed. Not sure if changes made any difference but looks good.
Fars was .5 cooler on high temperature but with <2 mph wind the Pro is working well.
I watched carefully today and the pro just responds quicker IMO and why spikes may be more prevalent. The 7714 is as slow as a tortoise at responding to any changes sometimes a 5 minute delay or no response at all. I pointed out a few with red dots you can see the larger spikes and deeper dips.
The 75 responds much, much faster than the Davis mounted 31.
Why, and how much is "much much"?
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Looks good today considering sub 2 mph average speed. Not sure if changes made any difference but looks good.
Fars was .5 cooler on high temperature but with <2 mph wind the Pro is working well.
I watched carefully today and the pro just responds quicker IMO and why spikes may be more prevalent. The 7714 is as slow as a tortoise at responding to any changes sometimes a 5 minute delay or no response at all. I pointed out a few with red dots you can see the larger spikes and deeper dips.
The 75 responds much, much faster than the Davis mounted 31.
Why, and how much is "much much"?
Can't speak for the much much part but the why would simply be because the 75 has less thermal mass. While the actual size of the 31 is small its mounted on a much larger pcb board surrounded by rubber potting. The 75 is mounted on a pcb hardly larger than the chip itself isolated somewhat by a very think neck. This means it will equalize with ambient air more quickly.
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Looks good today considering sub 2 mph average speed. Not sure if changes made any difference but looks good.
Fars was .5 cooler on high temperature but with <2 mph wind the Pro is working well.
I watched carefully today and the pro just responds quicker IMO and why spikes may be more prevalent. The 7714 is as slow as a tortoise at responding to any changes sometimes a 5 minute delay or no response at all. I pointed out a few with red dots you can see the larger spikes and deeper dips.
The 75 responds much, much faster than the Davis mounted 31.
Why, and how much is "much much"?
simply be because the 75 has less thermal mass.
Thank you.
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Here's a couple of graphs of my 1-min max and min temp obs. This is with a 40 CFM FARS and no filter for either sensor. The first one is the Davis SHT31 and the 2nd is the home brew SHT75 (different days).
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These 75s perform like a Vaisala probe.
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If I read this right, the 75 has much wilder swings than the 31. So, with the 75 it could literally display 75F one second then 70 the next? If so, not what I'd want, it took me long enough just to get use to the 31's swings.
No wonder why ASOS's use an averaging algorithm.
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If I read this right, the 75 has much wilder swings than the 31. So, with the 75 it could literally display 75F one second then 70 the next? If so, not what I'd want, it took me long enough just to get use to the 31's swings.
No wonder why ASOS's use an averaging algorithm.
That's a little extreme. my biggest 1 min swings are generally 2-3F and usually during the day with a lot of mixing. I decouple easily at night, but occasionally we'll get a puff of wind to mix down some slightly warmer air aloft. That's what those nighttime spikes are.
I am also heavily forested to the west of my property. So there's a bit of a battleground in the early evening between that and the warmer, more mixed air over my field. You can actually feel the temp change on your skin sometimes depending on the direction of the wind. Eventually the field decouples fully and we slip into a more stable, cooler airmas at the surface.
Randy's response is probably somewhat cut back with the filter and the passive shield. I'd be interested to see how his 75 performs in the suped up FARS.
Edit...just wanted to add that I don't think most of you would see the swings on your 75s that I see. From what I've seen of the siting around all of your stations (Valentine/Tucson/Victoria), your geography is fairly consistent for many square miles around you. My clearing surrounded by tall pine forest acts like a seabreeze when the wind and mixing aren't strong enough. I'm on the north side of a hill too, so we struggle to lose surface moisture so the evapotranspiration keeps the dewpoints a little higher and the temp a bit lower (again, when mixing is weak). My dewpoints tend to fall more in line with ASOS during the cold season.
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Home from work. Here is what is now yesterday's graph. Looks like FARS ran a little cooler overall again today.
Highs / Lows
FARS 92.1 / 69.4
PRO 92.9 / 69.3
(https://beta-static.photobucket.com/images/a541/hwcorder/s0/9f15d856-5f33-4d9a-b11f-867ec5cf345a-original.png?width=1920&height=1080&fit=bounds) (https://beta.photobucket.com/u/hwcorder/p/9f15d856-5f33-4d9a-b11f-867ec5cf345a)
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An update on the Barani standard shield, i got an email from Jan and he said that painting the bottom of the plates black offers some improvement on the performance of the standard shield. I emailed Randy and told him about this so i could get him all excited and he would try it and i could wait to see how it worked out before trying it myself :lol:. That way he could find out and tell us how hard or easy it is. I really think this is a good plan =D>.
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An update on the Barani standard shield, i got an email from Jan and he said that painting the bottom of the plates black offers some improvement on the performance of the standard shield. I emailed Randy and told him about this so i could get him all excited and he would try it and i could wait to see how it worked out before trying it myself :lol:. That way he could find out and tell us how hard or easy it is. I really think this is a good plan =D>.
What Jerry didn't know, I already had updated shield with black so when I heard paint I did the whole inside flat camo brown. :lol:
Oh well maybe it will help.
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Looks good today considering sub 2 mph average speed. Not sure if changes made any difference but looks good.
Fars was .5 cooler on high temperature but with <2 mph wind the Pro is working well.
I watched carefully today and the pro just responds quicker IMO and why spikes may be more prevalent. The 7714 is as slow as a tortoise at responding to any changes sometimes a 5 minute delay or no response at all. I pointed out a few with red dots you can see the larger spikes and deeper dips.
The 75 responds much, much faster than the Davis mounted 31.
Why, and how much is "much much"?
Can't speak for the much much part but the why would simply be because the 75 has less thermal mass. While the actual size of the 31 is small its mounted on a much larger pcb board surrounded by rubber potting. The 75 is mounted on a pcb hardly larger than the chip itself isolated somewhat by a very think neck. This means it will equalize with ambient air more quickly.
So why can't we just leave the 31 off the pcb and let it "dangle" inside the sensor chamber and maybe we get better response? Just trying to think outside the box here.
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Probably could, but I'd at least secure it some how to keep it from banging the chamber's wall constantly. Besides, with a proper fan, the effect should be somewhat mitigated.
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Pro +.7 sun broke out end of day.
Was still -3° below airport even using the +.7 on pro. Would of been a -4° cooler day using the FARS shield.
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With 5 mph wind the Pro wins slightly. What Jerry see's daily.
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Another good day for Pro. It's running slightly better than the others even with light winds. I removed the top plates this afternoon and didn't see any changes so leaving off. I did make a change with the standard shield yesterday with interior painted krylon fusion ultra flat camo brown.
Shield is running with the others now. Remember the 7714 is also black on the interior so the only stock shields are the Pro and Davis FARS.
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Update, since painting the standard shield interior black the pro and standard have been running pretty much the same on temperature. Any difference is usually .5 or less and doesn't last for that long of a time. It looks like the lower cost standard shield is a good shield when painted black inside. Just a little work and you have a low cost winner. Taking the shield a part to paint it is scary with it being helix design it goes together in pieces that spiral around from top to bottom, i did it so it can be done just pay attention to how it comes apart.
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Update, since painting the standard shield interior black the pro and standard have been running pretty much the same on temperature. Any difference is usually .5 or less and doesn't last for that long of a time. It looks like the lower cost standard shield is a good shield when painted black inside. Just a little work and you have a low cost winner. Taking the shield a part to paint it is scary with it being helix design it goes together in pieces that spiral around from top to bottom, i did it so it can be done just pay attention to how it comes apart.
Jan Barani in email suggest using a flat black latex with low VOC. He said reason they don't do the Pro everywhere and only do the inner black shield is desert and arctic locations will chip the paint off with fine granules.
The only low VOC paints I can find are interior house paints, none of the spray paints for plastic I can find qualify.
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Update, since painting the standard shield interior black the pro and standard have been running pretty much the same on temperature. Any difference is usually .5 or less and doesn't last for that long of a time. It looks like the lower cost standard shield is a good shield when painted black inside. Just a little work and you have a low cost winner. Taking the shield a part to paint it is scary with it being helix design it goes together in pieces that spiral around from top to bottom, i did it so it can be done just pay attention to how it comes apart.
Jan Barani in email suggest using a flat black latex with low VOC. He said reason they don't do the Pro everywhere and only do the inner black shield is desert and arctic locations will chip the paint off with fine granules.
The only low VOC paints I can find are interior house paints, none of the spray paints for plastic I can find qualify.
Ask Mr Jan Barani what 'brand' paint HE uses and if it (or equivalent) is available in USA.
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I found a flat black spray paint without voc's at Lowes but it is not for plastic and their primer is recommended. I would think the primer will be covered by the black so should hold down any voc's.
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I found a flat black spray paint without voc's at Lowes but it is not for plastic and their primer is recommended. I would think the primer will be covered by the black so should hold down any voc's.
Do you remember the brand name? I've seen no voc primer advertised in spray somewhere.
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Looks like this will work on plastic and is low voc.
Good luck finding in flat black. I did find gloss black. Krylon Eco Guard Latex Spray Paint
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How about this stuff https://www.zoro.com/rust-oleum-spray-paint-black-12-oz-1676830/i/G2459143/
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How about this stuff https://www.zoro.com/rust-oleum-spray-paint-black-12-oz-1676830/i/G2459143/
Looks good, I found this too. https://www.amazon.com/gp/product/B002JG8MNU/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1
UPDATE: They sent Iron guard instead of ECO so refunded order. Still haven't updated image,
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hello everyone, I'm mauro from Italy
this is my new test configuration, I hope you like it
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davis vp2 2018 version
meteoshield pro with sensirion sht20
davis modified version with sensirion sht20
deltaohm hd2013 professional rain gauge with pulse counter
the sensirions were calibrated and aligned in the climatic chamber
in next days I will post my test, if you like
sorry for my bad english
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Really nice looking set up and will be interested in your findings.
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Really nice looking set up and will be interested in your findings.
Thank Jerry, I'm honored you like ;)
yesterday we had a sky partly cloudly, a moderate wind from NNW with average speed of 1m/s and 4/ms gusts at 2mt height
maximum solar radiation was 780w/mq
this is the result, the graph show only data from 10 am, from today the graph will be complete
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As you can see, the pro has very better performance, the vp2 was obviously the worst and the modified davis has a good performances with only 0,3° over the meteoshield pro, the davis is not yet totally ready, I'm studiyng other moods to this project
Mauro
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I tested one of the vp2 pro shields a few years ago, even tried to make it better adding more plates. My test notes say +4.5F vs the Davis FARS.
Different story with the Davis 7714 it's almost as good as the Pro if painted black inside on bottom sensor plate and roof. Problem I see with the Davis 7714 is slow response to changes and reason it does so well.
The meteoshield rapid response to change is a nice plus for any passive shield but may play against it when conditions are calm.
The one thing I didn't do is paint interior on VP2 pro passive black. It did wonders on the Meteo Standard shield. I still can't find any low VOC spray paint however. The black low VOC paint I ordered the other day ECO GUARD isn't available any longer where I ordered.
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I tested one of the vp2 pro shields a few years ago, even tried to make it better adding more plates. My test notes say +4.5F vs the Davis FARS.
Different story with the Davis 7714 it's almost as good as the Pro if painted black inside on bottom sensor plate and roof. Problem I see with the Davis 7714 is slow response to changes and reason it does so well.
The meteoshield rapid response to change is a nice plus for any passive shield but may play against it when conditions are calm.
The one thing I didn't do is paint interior on VP2 pro passive black. It did wonders on the Meteo Standard shield. I still can't find any low VOC spray paint however. The black low VOC paint I ordered the other day ECO GUARD isn't available any longer where I ordered.
my davis is a little more complicated, is assembled using eight plates of the vp2, two upper closed, four open, two lower closed.
above the screen a white aluminum plate above and black underneath, on top of a further aluminum plate and ASA hat, both recovered from a Comet f8110 screen.
below some images in detail
next step I will add an Aerogel plate thru the metal plates and I will change the fixing metal bars with teflon bars
in a second moment I would like to proceed to apply black paint on the bottom of davis plates
please, forgive my mistakes due to my horrible english
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Actual situation, sunny, wind 0,8m/s from NW
solar radiation 724w/mq
Davis vp2 26,2 °C
Davis 8 plates 26,1 °C
Meteoshield Pro 25,7 °C
Bye
Mauro
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Try painting plate where sensor is mounted black and plate on bottom black. That should give good results if sensor is sandwiched between 2 black plates. top of sensor plate you can leave white.
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Hey Randy his English is a lot better than our Italian :lol:
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Try painting plate where sensor is mounted black and plate on bottom black. That should give good results if sensor is sandwiched between 2 black plates. top of sensor plate you can leave white.
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OK, surely I will do, and about the bottom plate, I think will not good to paint it entirely, I think it's better to paint only the part inside, like this?
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Mauro
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Yes and make sure the plate where sensor is mounted too. Only the side where sensor is at.
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Yes and make sure the plate where sensor is mounted too. Only the side where sensor is at.
Ok Randy,
I understood and many thanks Jerry, I know my English is terrible, but I'm happy to be understandable ;)
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Yes and make sure the plate where sensor is mounted too. Only the side where sensor is at.
Ok Randy,
I understood and many thanks Jerry, I know my English is terrible, but I'm happy to be understandable ;)
Believe me your english is much better than my Italian. :-)
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Yes and make sure the plate where sensor is mounted too. Only the side where sensor is at.
Ok Randy,
I understood and many thanks Jerry, I know my English is terrible, but I'm happy to be understandable ;)
Believe me your english is much better than my Italian. :-)
Thank you Randy ;)
today I've ordered new two kits of davis plates to prepare a new radiation shield with teflon bar and inside black paint as your instructions
yesterday results
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mauro63 have you tried the Davis 7714. Do the same with black paint. Ryan at Scaled Instruments does ship international.
https://www.scaledinstruments.com/shop/davis-instruments/davis-7714-passive-radiation-shield/
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mauro63 have you tried the Davis 7714. Do the same with black paint. Ryan at Scaled Instruments does ship international.
https://www.scaledinstruments.com/shop/davis-instruments/davis-7714-passive-radiation-shield/
Thank you Randy, 7714 was my first solar radiation shield a long time ago, in the past I've bought about four davis 7714, it was my preferred solar radiation shield for a long time but, one day, I've tried the barani meteoshield and, from that moment I left the 7714 due to very poor perfomances compared to barani meteoshield
the performance of 8 davis plates, the same plates of vp2, are better,at least in my field, than the 7714
now I have two davis 7714 yet, in one of them I have a ds18b20 connected to a cabled datalogger, another one for some tests.
I,ve also tested a Vaisala dtr-503 (good but not as the barani pro), a Cometsystem f8110 (not good, similar performances of 7714), two Rika versions with very poor perfomances
I'm also testing the Barani meteoshield standard, but it's not installed at the moment, I'm waiting a new datalogger with two external probe and 0,2 °C accuracy
Try painting plate where sensor is mounted black and plate on bottom black. That should give good results if sensor is sandwiched between 2 black plates. top of sensor plate you can leave white.
about these step, do you have some tests to confirm the black sandwiched system superiority?
in my personal knowledge all the inner plates should be black painted
sorry, probably my questions could be ridiculous, in this case please forgive me
Mauro
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about these step, do you have some tests to confirm the black sandwiched system superiority?
in my personal knowledge all the inner plates should be black painted
sorry, probably my questions could be ridiculous, in this case please forgive me
Mauro
No, if you can paint the inside of louvers it would be better but may be difficult.
I've found the 7714 with sensor plate and bottom plate painted black has very good performance, superior to the VP2 shield. I never tried paint on the VP2 shield however.
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Anyone ever try painting the inside of the FARS plates? ;)
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Still haven't found any low VOC spray paint. Seems they got bad reviews according to consumer reports so looks like in 2018 not many if any still around. Interior/exterior water based house paints may be all that's left, the brush on variety.
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I believe water-based flat exterior Latex™ paint is all you'll find.
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This paint is shown at Home Depot to be voc compliant just need to use a primer with it. https://www.homedepot.com/p/Quick-Color-10-oz-Flat-Black-General-Purpose-Aerosol-Paint-J285
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This paint is shown at Home Depot to be voc compliant just need to use a primer with it. https://www.homedepot.com/p/Quick-Color-10-oz-Flat-Black-General-Purpose-Aerosol-Paint-J285
Click on it Jerry says unavailable. If you show it, you may have it cached in browser.
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about these step, do you have some tests to confirm the black sandwiched system superiority?
in my personal knowledge all the inner plates should be black painted
sorry, probably my questions could be ridiculous, in this case please forgive me
Mauro
No, if you can paint the inside of louvers it would be better but may be difficult.
I've found the 7714 with sensor plate and bottom plate painted black has very good performance, superior to the VP2 shield. I never tried paint on the VP2 shield however.
Last year I carried out some tests of comparison between vp2, meteoshield pro, davis 7714 and davis 5 plates, the same as vp2 but decoupled from the transmitter group
here are some pictures
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In those tests highlighted the poor performance of the 5 plates of the vp2 once removed from the transmitter group, the 7714 was placed in half, obviously the meteoshield was the best of all
The 5 plates of the vp2 is instead able to give good performance with its original position under the pluviometer thanks to the shadow created by the cone and the transmitter box, well visible shadow in the following image
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this shadow allows the sensor to work avoiding stagnation of hot air in the small screen ensuring acceptable performance in the presence of a minimum of natural ventilation
Mauro
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-Well there you go again a day late and a dollar short :lol:
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-Well there you go again a day late and a dollar short :lol:
I checked the other day at the SDS and VOC's looked high anyway. Here is link if you look at SDS is says odor is solvent like.
https://www.rustoleum.com/product-catalog/industrial-brands/industrial-choice/spray-paint/1600-system-multi-purpose-enamel-sprays
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-Well there you go again a day late and a dollar short :lol:
I checked the other day at the SDS and VOC's looked high anyway. Here is link if you look at SDS is says odor is solvent like.
https://www.rustoleum.com/product-catalog/industrial-brands/industrial-choice/spray-paint/1600-system-multi-purpose-enamel-sprays
IF you have the time, spray and then let "sit" for a couple (or more?) months, before assembling.
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I read that also as paint dries the VOC's diminish. I used a hair dryer inside shield and let run for 20 minutes or so helping the drying process.
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Here are today's graphs Pro vs Davis Fars and 7714. Light winds full sun. Haven't had many light wind full sun days.
As you can see the Pro is better than 7714 even painted black inside.
Still on very light wind days the FARS works best for me. But just the opposite on windier days 10 mph+ the Pro runs average 1/2° lower than the FARS. Another Pro shield remote site has more wind so shield is superior. In town however with less air movement I'll be sticking with the FARS as primary shield.
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Meanwhile, I made some changes to my modified davis, the plates are now 10, the upper bracket has been replaced with a davis
the second plate from the top is partially covered internally by a black Teflon disk, the same thing on the second lower closed plate, now the sensor is between two black plates
I kept the double bottom closed plate with fixing system of the ring sensors as in professionals radiation shields.
I hope you like it, it has been installed from 2 hours, from tomorrow the first results
Mauro
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Looks good,
If you don't get the results you want, try a closed plate (black on top side) on the very bottom instead of open plate like it is.
I'm not sure adding more open plates helps shield. You are adding more mass to absorb heat. Just a thought...
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Looks good,
If you don't get the results you want, try a closed plate (black on top side) on the very bottom instead of open plate like it is.
I'm not sure adding more open plates helps shield. You are adding more mass to absorb heat. Just a thought...
thanks,
the bottom plate is not open, it's closed by from a fixing ring for the sensor tube
practically the bottom plate is as if it were entirely closed
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results today, only from 1 pm, since the screen was installed around 12 am
I would say very interesting results
day characterized by wind always above 1m/sec and maximum solar radiation of 700w / mq
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I see looks good. =D>
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I see looks good. =D>
Thanks ;)
I have to make two changes yet:
-replace steel bars and hardware with teflon bars and screws
-to place an airgel disc between the top metal plate and the first upper plate
as you can see, during the temperature drop, the meteoshield pro is much faster than the modified davis, the reason could be, as you rightly said, in the number of open plates, after the next changes I can try to reduce them
Mauro
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for those who might be interested, from some days I'm testing the new microstation Barani Meteohelix IoT Pro
the station is connected to the Sigfox network, at the moment we are working on improving the web interface
the parameters measured with the integrated sensor, directly derivated from Meteotemp probe are:
temperature with +o-0,2° C accuracy
humidity with +0- 1,8% accuracy
barometric pressure
solar radiation
the station is solar powered with 6 months of life without solar radiation
Mauro
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link
https://www.baranidesign.com/meteohelix-pro-weather-station/ (https://www.baranidesign.com/meteohelix-pro-weather-station/)
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today we had a very disturbed day, overcast skies, wind with gusts of up to 10m / sec, a day so useless for the tests but good to evaluate the alignment of the sensors
I am attaching the screen
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Mauro
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How high should I install the temp/hum probe in the pro shield?
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How high should I install the temp/hum probe in the pro shield?
HI,
I've tested for a long time meteoshield pro and standard, usually I install my sensor at half height of the internal chambre, I've tried to move up and down without appreciable differences, only if I move the sensor down, near the connector I've noticed lower minimum temperature with clear sky e no wind
you can try by yourself, the position inside the screen is easy to chose without disassembling anything, if you have prepared a bar to fix the sensor
Mauro
this is my solution, the bar is the older, the new have more lenght and is not pvc but teflon ;)
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Good observation I also noticed the lower position matched clear night time better with FARS.
I've found the standard blacked out inside with paint works just as well as Pro and fits the Davis SHT31 better without trimming sensor board.
I'm still testing the shields but in town I have too many windless days to feel comfortable with a passive shield. When I say windless I mean shield level 0-1 mph average speed over extended periods where heat builds.
My second station outside of town these work just fine where the wind rarely goes below 3 mph and most of the time runs 5+mph at shield level daytime.
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So basically, if I have the sensor closer to the connector, it won’t take away any of the benefits of the shield during the daytime?
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I thought the meteo shield did a little better toward the lower end of shield. Bottom 4" or so vs higher up in shield. If you look at the short meteo sensors they sell all are short toward bottom.
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I thought the meteo shield did a little better toward the lower end of shield. Bottom 4" or so vs higher up in shield. If you look at the short meteo sensors they sell all are short toward bottom.
Gotcha. Thanks!
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About the test of Meteohelix IoT Pro of Barani, the Barani micro weather station, after two weeks, I can confirm that the performances are the same of Meteoshield Pro, so very accurate ;)
we are working now to fix some little improvements on web interface, hope you like ;)
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Got my friend’s shield up and running with the Sensirion SHT-75
Now I just got to get my shield hooked up at my home station and I’ll be all set and ready to go this winter.
My friend and I had to rednecked our way to get the Barani shield mounted on the pole
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Got my friend’s shield up and running with the Sensirion SHT-75
Now I just got to get my shield hooked up at my home station and I’ll be all set and ready to go this winter.
My friend and I had to rednecked our way to get the Barani shield mounted on the pole
Couldn't you either reverse the U-bolts (nuts & washers against Barani support) or even possibly use the VP2 U-bolt(s) to hold both units?
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Got my friend’s shield up and running with the Sensirion SHT-75
Now I just got to get my shield hooked up at my home station and I’ll be all set and ready to go this winter.
My friend and I had to rednecked our way to get the Barani shield mounted on the pole
Couldn't you either reverse the U-bolts (nuts & washers against Barani support) or even possibly use the VP2 U-bolt(s) to hold both units?
Most likely not. The holes on the Barani shield bracket are placed there for a skinnier pole. I lowered the rain gauge for more reliable rain readings. Also didn’t want the rain canister block any wind from the shield.
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Got my friend’s shield up and running with the Sensirion SHT-75
Now I just got to get my shield hooked up at my home station and I’ll be all set and ready to go this winter.
My friend and I had to rednecked our way to get the Barani shield mounted on the pole
Couldn't you either reverse the U-bolts (nuts & washers against Barani support) or even possibly use the VP2 U-bolt(s) to hold both units?
Most likely not. The holes on the Barani shield bracket are placed there for a skinnier pole. I lowered the rain gauge for more reliable rain readings. Also didn’t want the rain canister block any wind from the shield.
you can use very strong plastic straps, the weight of the meteoshield is not high, the straps are quick to assemble and remove, I personally use them often with the meteoshield without a problem
Mauro [ You are not allowed to view attachments ]
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Couple metal hose clamps will work also.
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Got my friend’s shield up and running with the Sensirion SHT-75
Now I just got to get my shield hooked up at my home station and I’ll be all set and ready to go this winter.
My friend and I had to rednecked our way to get the Barani shield mounted on the pole
Couldn't you either reverse the U-bolts (nuts & washers against Barani support) or even possibly use the VP2 U-bolt(s) to hold both units?
Most likely not. The holes on the Barani shield bracket are placed there for a skinnier pole. I lowered the rain gauge for more reliable rain readings. Also didn’t want the rain canister block any wind from the shield.
you can use very strong plastic straps, the weight of the meteoshield is not high, the straps are quick to assemble and remove, I personally use them often with the meteoshield without a problem
Mauro [ You are not allowed to view attachments ]
We tried with zip ties (not the strongest ones) and it didn’t do bad execept the top part of the bracket wouldn’t stay level. It wasn’t stable. We just use what we had and we know that sucker ain’t going anywhere.
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I installed my Barani Pro shield at my house yesterday and noticed that the company didn’t included the 3 lock washers and hex nuts for securing the shield on the bracket mount (like the instructions said it did). Had to go by the store to get some. But other than that, it’s up and running.
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Looks good, now for some reports on performance. I have been running my station on my rm young fars for the last few weeks comparing it to the pro shield and i just switched back to the pro yesterday. It looks like the pro can hold it's own against one of the better fars around. I think as we get later into the year and solar energy is less the fars is not going to be as important as it might be in the summer when solar heating is at max. The pro has been doing just fine in comparison and the main difference right now is the fars will show a higher temp up to a degree higher and i think that is because the fars is more responsive to temp changes than the pro which is a little slower in response to quick temp changes. With just a little wind the pro has been running about a .5 degree lower than the fars and with no wind runs the same as the fars. This seems to be because of less solar heating this time of year and will be proved out as the next summer cycle comes along. Will just take time to get all the ducks in a row with this stuff.
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Looks good, now for some reports on performance. I have been running my station on my rm young fars for the last few weeks comparing it to the pro shield and i just switched back to the pro yesterday. It looks like the pro can hold it's own against one of the better fars around. I think as we get later into the year and solar energy is less the fars is not going to be as important as it might be in the summer when solar heating is at max. The pro has been doing just fine in comparison and the main difference right now is the fars will show a higher temp up to a degree higher and i think that is because the fars is more responsive to temp changes than the pro which is a little slower in response to quick temp changes. With just a little wind the pro has been running about a .5 degree lower than the fars and with no wind runs the same as the fars. This seems to be because of less solar heating this time of year and will be proved out as the next summer cycle comes along. Will just take time to get all the ducks in a row with this stuff.
I don’t think any passive shield is going to beat a good FARS when there is very little wind. But I do think the Pro shield along with the 75 is a great investment for Davis users
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I'm seeing less need for FARS also as we are in fall mode even relative calm windless days.
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Where my station is located (in an enclosed area) it’s hard to say how good the pro shield is doing. There is another Davis station with the Barani Pro shield and a 75 sensor also located .8m from me. That station’s recorded highs are typically around 1-2° cooler than my highs.
But I’m thinking my station at my house deals with a lack of “mixing” of the air during lighter wind days compared to most well sited stations. The result is typically warmer temps and higher DPs at times compared to other nearby stations.
But it does seems like the pro shield produces really good response time for temp and humidity readings. I’ve seen as much as .3° jump in temp and 4-5% in RH per update cycle. Then again, I’m sure part of that is due to the 75.
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I will say that insects are still crawling on the shield like they don’t give a flip. Lol
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I will say that insects are still crawling on the shield like they don’t give a flip. Lol
Same here I had ants trailing on mine...
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This is ugly what I'm seeing with the pro and standard shields over snow cover. Almost opposite of the claim of reducing solar glare off snow. This is full ground snow cover and blazing sunshine difference is both Meteoshields Pro running plus 3-4° F warmer than Davis FARS. This really is a head scratcher #-o why snow reflection is this bad with these shields.
I referenced the airport only mile away making sure something wasn't wrong with FARS thermometer and both reading the same 37°.
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Wow...interesting. I guess when the albedo is that high with fresh snow cover it's like the sun is shining directly from the ground and upward onto the black underside of the plates.
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Actually your standard has all white plates, correct? Or did you paint the underside a flat black?
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I painted the inside on standard flat brown to reduce glare.
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Update shields are coming together and look normal again but most of snow cover is also gone. +1 on standard , + .5 on Pro. I'll have to see what happens next snow.
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Sent Jan my concern about the snow reflection and all the data logger information plus timelapse when snow melted. You can see the shields come together after the melt on this graph.
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Jerry pointed this out in PM we may be looking at something different here because the Pro shield is especially protected with the inner black shield for this type of reflection and protection. I wish I would of had the 7714 going at same time. Next time I'll have in service and see if all passive shields react the same or just the Meteoshields.
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IMO: It’s false advertising from Barani to say that insects and spiders don’t like your shield. Already had a spider built a web on the shield and laid some eggs on the black louver...
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My new fars radiation solar shield, is a modified version of davis 24h, inside use the same sensor used to test older version and perfectly alligned to meteoshield pro sensor
is installed from yesterday at 2 pm
hope you like ;)
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yesterday graph comparision, clear, low wind and about 550w/mq solar radiation
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Mauro
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Did you include the insulating sleeve?
https://www.scaledinstruments.com/wp-content/uploads/2014/09/24hr_fars_Exploded_Diagram.pdf
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Did you include the insulating sleeve?
https://www.scaledinstruments.com/wp-content/uploads/2014/09/24hr_fars_Exploded_Diagram.pdf
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no randy, I did not do it, this is only first test, I think I will do a lot of improvement
Mauro
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today we did not have a useful day, the sky was covered all day, so the differences between screens are canceled
however, below today's partial graph
Mauro
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Hi,
today was characterized by considerable changes in temperature due to the cloud cover at times and, sometimes, intense sun, the difference in reactivity is remarkable, the extremes have been mitigated by the wind, constantly present throughout the day
next week I will start a new project, more accurate construction and better materials, especcialy regarding concentric tubes isolation
;)
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...the fars goes back up to the 1 degree higher which shows the fars temp is being affected by the solar heating of the sun on the shield which is shown in the specs of the shield...
I would argue that all Davis specs are suspect after the move they've pulled with humidity. In any event, Davis is assuming you're using their fan and power section that produces just under 1 m/s flow in the daytime. If memory serves you're running the fan at 3V off a wall wart during the day, but I'm not sure how much that increases the fan rate. Any idea?
According to the research I've read, 1 m/s is the line below which significant errors occur. The pro/reference gear is all above 2 m/s (much of it 3 m/s or higher) to avoid under aspiration.
I’ve got the FARS 6323 sensor array (about 6 months old) and I’m curious what you’re referencing with the ‘move’ you say that Davis pulled with RH. My readings seem on target, but perhaps I’m not aware of some issue. Are you saying their RH specs are off?
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Sent Jan my concern about the snow reflection and all the data logger information plus timelapse when snow melted. You can see the shields come together after the melt on this graph.
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What did Jan say about your temperature issues with snow cover?
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Sent Jan my concern about the snow reflection and all the data logger information plus timelapse when snow melted. You can see the shields come together after the melt on this graph.
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What did Jan say about your temperature issues with snow cover?
A little Surprised. Most of the issues with passive shields are due to location and lack of wind. These are great as long as a little breeze is going. My other Pro shield doesn't have issues at all, just in town.
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Sent Jan my concern about the snow reflection and all the data logger information plus timelapse when snow melted. You can see the shields come together after the melt on this graph.
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What did Jan say about your temperature issues with snow cover?
A little Surprised. Most of the issues with passive shields are due to location and lack of wind. These are great as long as a little breeze is going. My other Pro shield doesn't have issues at all, just in town.
Gotcha. You’re definitely right about the need for a little wind. What are your differences between the FARS and the Pro shield when the wind is dead calm? I’m believing that the black louvers are increasing the error of temperature readings during calm wind conditions.
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...the fars goes back up to the 1 degree higher which shows the fars temp is being affected by the solar heating of the sun on the shield which is shown in the specs of the shield...
I would argue that all Davis specs are suspect after the move they've pulled with humidity. In any event, Davis is assuming you're using their fan and power section that produces just under 1 m/s flow in the daytime. If memory serves you're running the fan at 3V off a wall wart during the day, but I'm not sure how much that increases the fan rate. Any idea?
According to the research I've read, 1 m/s is the line below which significant errors occur. The pro/reference gear is all above 2 m/s (much of it 3 m/s or higher) to avoid under aspiration.
I’ve got the FARS 6323 sensor array (about 6 months old) and I’m curious what you’re referencing with the ‘move’ you say that Davis pulled with RH. My readings seem on target, but perhaps I’m not aware of some issue. Are you saying their RH specs are off?
Sorry, didn't get a notification for this post.
Yes, there is an issue with humidity measurements. In fact, there's a thread with over 1300 posts explaining this in detail: https://www.wxforum.net/index.php?topic=34658.0 (https://www.wxforum.net/index.php?topic=34658.0).
Long story short... Davis claims the sensor measures within 2% of reality across the spectrum https://www.davisinstruments.com/product_documents/weather/spec_sheets/6152_62_53_63_SS.pdf (https://www.davisinstruments.com/product_documents/weather/spec_sheets/6152_62_53_63_SS.pdf). Some of us have seen errors as large as +8-10% in the middle ranges (30-80%) with an accompanying dry bias above 95% that can worsen over time. Davis acknowledged the concerns earlier this year but has taken no action since.
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Sorry, didn't get a notification for this post.
Yes, there is an issue with humidity measurements. In fact, there's a thread with over 1300 posts explaining this in detail: https://www.wxforum.net/index.php?topic=34658.0 (https://www.wxforum.net/index.php?topic=34658.0).
Long story short... Davis claims the sensor measures within 2% of reality across the spectrum https://www.davisinstruments.com/product_documents/weather/spec_sheets/6152_62_53_63_SS.pdf (https://www.davisinstruments.com/product_documents/weather/spec_sheets/6152_62_53_63_SS.pdf). Some of us have seen errors as large as +8-10% in the middle ranges (30-80%) with an accompanying dry bias above 95% that can worsen over time. Davis acknowledged the concerns earlier this year but has taken no action since.
Thanks. So is this error only associated with the new sensor with Davis' claimed improved accuracy? Does it affect all sensors or only some? Personally I haven't noticed this issue. I live about 15 minutes from the NWS Upton, NY office. My RH readings are always within 2% of theirs.
My other benchmark is 2 of the 3 weather apps I use (WeatherBug, TWC & Accuweather) are also almost always within 2% of my readings for my area at virtually any RH. Granted I don't know where they are actually pulling these readings from, but still. Interestingly many of the neighboring stations on WU are often 5-10% above mine in the area of 60-80%. However many of those are Ambient Weather stations. Having owned one of those, I can attest to the fact that RH generally reads high, particularly in the upper regions of 90% & above. Of the Davis stations I see in my area, only 1 is a fan aspirated unit.
So it's interesting that I'm very close to the readings provided by the relatively close NWS Upton, NY office, as well as 2 of the 3 weather apps for my area. So I'm not sure of what to make of this.
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Sorry, didn't get a notification for this post.
Yes, there is an issue with humidity measurements. In fact, there's a thread with over 1300 posts explaining this in detail: https://www.wxforum.net/index.php?topic=34658.0 (https://www.wxforum.net/index.php?topic=34658.0).
Long story short... Davis claims the sensor measures within 2% of reality across the spectrum https://www.davisinstruments.com/product_documents/weather/spec_sheets/6152_62_53_63_SS.pdf (https://www.davisinstruments.com/product_documents/weather/spec_sheets/6152_62_53_63_SS.pdf). Some of us have seen errors as large as +8-10% in the middle ranges (30-80%) with an accompanying dry bias above 95% that can worsen over time. Davis acknowledged the concerns earlier this year but has taken no action since.
Thanks. So is this error only associated with the new sensor with Davis' claimed improved accuracy? Does it affect all sensors or only some? Personally I haven't noticed this issue. I live about 15 minutes from the NWS Upton, NY office. My RH readings are always within 2% of theirs.
My other benchmark is 2 of the 3 weather apps I use (WeatherBug, TWC & Accuweather) are also almost always within 2% of my readings for my area at virtually any RH. Granted I don't know where they are actually pulling these readings from, but still. Interestingly many of the neighboring stations on WU are often 5-10% above mine in the area of 60-80%. However many of those are Ambient Weather stations. Having owned one of those, I can attest to the fact that RH generally reads high, particularly in the upper regions of 90% & above. Of the Davis stations I see in my area, only 1 is a fan aspirated unit.
So it's interesting that I'm very close to the readings provided by the relatively close NWS Upton, NY office, as well as 2 of the 3 weather apps for my area. So I'm not sure of what to make of this.
Don't want to take this too off topic. So I'll be brief. Feel free to private message me for follow ups.
It's likely this has been a problem for years. I've personally confirmed it on my SHT11 and SHT15 sensors using a variety of methods. But mainly we've been concerned with the SHT31 as it is the currently available sensor suite (the others mentioned have been discontinued).
The best way to check for problems is to reference an official station's dew point, not humidity since that's dependent on temperatures matching between stations. Being so far out on Long Island makes it difficult to compare your station to others even within a few miles. If you're truly concerned, I'd either take my ISS to the airport/NWS office and compare it there or get a trustworthy device (a Kestrel Drop is about $99 and works with a smartphone).
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What are your differences between the FARS and the Pro shield when the wind is dead calm? I’m believing that the black louvers are increasing the error of temperature readings during calm wind conditions.
Still about 2°, this is with (.1) mph at shield level wind speed even with low sun angle.
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I’m basically getting the same results here in Alabama. But that’s the risk I’ll rather take than having to worry about maintaining the FARS.
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Just an update to the old post, Jan at Barani has sent Valentine weather and myself a new version of the Pro shield for testing. It is supposed to have improved low wind results and mine should be here Monday and i am going to test it against a Davis fars. I and i am sure Randy will post some results after we get things going.
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Just an update to the old post, Jan at Barani has sent Valentine weather and myself a new version of the Pro shield for testing. It is supposed to have improved low wind results and mine should be here Monday and i am going to test it against a Davis fars. I and i am sure Randy will post some results after we get things going.
Nice!!!
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Yes looking forward to the new shield design. The improvement includes a special all-black tested color interior to reduce reflection and a special plastic to reduce heat buildup at low wind speeds.
Ideally, Barani is looking for a passive shield that works well-reducing snow reflection and can rival FARS shields in low wind speed situations. Have to give them credit for continuing advancement, unlike some developers we know.
They also have a new design rain gauge that can handle even high rainfall rates I'll eventually be testing. The heated unit will be available for testing toward the end of 2020.
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But that’s the risk I’ll rather take than having to worry about maintaining the FARS.
I see that as a double edged sword...no fan, bug maintenance...stock fan, bug and fan maintenance...case fan, both problems solved. Of course not all can play.
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They also have a new design rain gauge that can handle even high rainfall rates I'll eventually be testing.
Manual, tipper, something else?
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They also have a new design rain gauge that can handle even high rainfall rates I'll eventually be testing.
Manual, tipper, something else?
Yes, its a tipper design.
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Oh, not what I was expecting you to say. Privy to anything else like diameter of the bucket, single or dual spoons, ect?
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All we need is a sensor that’s not Sensirion (preferably HYT-221) probe and a new Davis transmitter and we will be good!
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All we need is a sensor that’s not Sensirion (preferably HYT-221) probe and a new Davis transmitter and we will be good!
If, I repeat, IF Davis has properly dealt with the 31 issue, which seems quite possible, that'll never happen with a VP2.
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Oh, not what I was expecting you to say. Privy to anything else like diameter of the bucket, single or dual spoons, ect?
I think the details of the gauges can be found on their website. My testing will be toward the end of the year because I requested a heated unit and they are not out yet.
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All we need is a sensor that’s not Sensirion (preferably HYT-221) probe and a new Davis transmitter and we will be good!
If, I repeat, IF Davis has properly dealt with the 31 issue, which seems quite possible, that'll never happen with a VP2.
Probably won’t but their EnviroMonitor can take I2C sensors
https://www.wxforum.net/index.php?topic=34658.1575
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Oh, not what I was expecting you to say. Privy to anything else like diameter of the bucket, single or dual spoons, ect?
I think the details of the gauges can be found on their website. My testing will be toward the end of the year because I requested a heated unit and they are not out yet.
Thanks! Sorry for all the questions, but how will you compare? RW, Stratus?
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Oh, not what I was expecting you to say. Privy to anything else like diameter of the bucket, single or dual spoons, ect?
I think the details of the gauges can be found on their website. My testing will be toward the end of the year because I requested a heated unit and they are not out yet.
Thanks! Sorry for all the questions, but how will you compare? RW, Stratus?
I'll compare it to Stratus as primary. I don't use the RW at home. I'm using a heated TR525 USW. The RW is at the remote station.
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Look forward to it!
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I got the pro in at noon today and have it out co-located with the fars and very early results look pretty good. I got a long way to go before things become clear. Today we had winds around 10 mph but did get a few short periods when the wind was calm and low at 1 to 4 mph and the new pro didn't miss a beat, temp stayed right with the fars, no spike due to low winds. Got to wait for one of the morning times when the sun is just coming up and no wind, that is the true test but just a quickie today and the fars max has been 62.3 and the pro 61.6.
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Got to wait for one of the morning times when the sun is just coming up and no wind, that is the true test
Unless the sensor in the passive is exposed to the sun's rays, I would think around solar noon with calm wind would be your best bet.
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Jerry's test shield is top link 113
https://www.wunderground.com/dashboard/pws/KTXVICTO113
https://www.wunderground.com/dashboard/pws/KTXVICTO6
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When wu is working here is the info site https://www.wunderground.com/dashboard/pws/KTXVICTO113
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Thanks I corrected the above links.
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Got to wait for one of the morning times when the sun is just coming up and no wind, that is the true test
Unless the sensor in the passive is exposed to the sun's rays, I would think around solar noon with calm wind would be your best bet.
I want to see calm wind with no more than 5 mph at anemometer height usually translates to 2-3 mph at the sensor level for a good test. The less wind the better. Between peak sun throughout the afternoon heat buildup into sunset are where my interest is and what I consider the most critical time.
For many areas like Arizona, it was almost impossible to get calm afternoons but here in Nebraska, it does happen more often so I should have some good comparison days.
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Got to wait for one of the morning times when the sun is just coming up and no wind, that is the true test
Unless the sensor in the passive is exposed to the sun's rays, I would think around solar noon with calm wind would be your best bet.
The less wind the better. Between peak sun throughout the afternoon heat buildup into sunset are where my interest is and what I consider the most critical time.
Well, that's the whole point, how the new shield compares to the aspirated in the worst case scenario, dead calm and full sun. My peak heat in the summer almost always occurs between 2:45ish and 3:30. Although I believe this is a wonderful passive shield, it will still never beat a good fan in a quality shield such as is the 24hr VP2's, nor should it.
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What i would want is a passive shield that has good performance at low wind speeds and acceptable in calm wind for a remote location where repairs might be iffy if a fan quits or night time batteries go bad. If this shield can keep the error around .5 or so i could live with that and i sure hope it does, time will tell.
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It would be a real breakthrough for passive shields for sure. Even +1F error with no wind I could live with. These actually do better in windy conditions but with so many calm days I was always drawn back to the FARS. Fingers crossed.
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Ok i am now in official test mode, got the fars running on the main site and the pro on the 113 wu site and the wind speed shown on the pro site is using my spare anny mounted just above the shield so will know real wind speed at shield height. Now time will tell the story.
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How much does the shield your testing out run? Funny how a temp. probe(s) can read 1.5 to 2 degrees higher even in overcast windy conditions during the day. I have 3 temp probes in a small bird house painted white inside and out with a open bottom in it; all of which tend to run higher than davis non-aspirated shield.
Thanks,
tweatherman
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If only the bottom of your bird house is vented and since heat rises....
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Yes very true but if I put holes in the top and sides rain will eventually get on the sensors.
Thanks,
tweatherman
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An upside-down container is essentially a heat trap. I would expect the sensors in there to read high.
Rich K.
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Just an update to the old post, Jan at Barani has sent Valentine weather and myself a new version of the Pro shield for testing. It is supposed to have improved low wind results and mine should be here Monday and i am going to test it against a Davis fars. I and i am sure Randy will post some results after we get things going.
Does the design of the new Pro looks any different?
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Yes there are a couple things that are different, the inside of the white shield is also black now and the mounting plate now holds the probe clamp instead of being on the shield itself, a lot easier to swap probes. So far the low wind speed readings are much improved compared to the old pro and today the wind has been mostly calm with winds when it blows up to 4 to 5 on average and for short periods of time. This morning the wind was mostly calm until nearly noon and the pro hung in there with the fars. The fars so far today has a max .4 degrees higher than the pro.
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What size sensors would fit inside of this shield?
Thanks,
tweatherman
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I really haven't measured it but it is pretty small inside the shield. Valentine weather probably knows more about that than i do, my sensors are homemade and pretty small to fit inside the shield.
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Yes there are a couple things that are different, the inside of the white shield is also black now and the mounting plate now holds the probe clamp instead of being on the shield itself, a lot easier to swap probes. So far the low wind speed readings are much improved compared to the old pro and today the wind has been mostly calm with winds when it blows up to 4 to 5 on average and for short periods of time. This morning the wind was mostly calm until nearly noon and the pro hung in there with the fars. The fars so far today has a max .4 degrees higher than the pro.
I wonder when they will be on sale?
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I think they are now.
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I would check first for the new shield availability.
A little video of differences. Jan told me in an email they changed the plastic material along with black color on the new shield reducing heat and reflection.
[youtube]https://www.youtube.com/watch?v=-Zp2TuF0Ifo&feature=youtu.be&t=10[/youtube]
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Here are a couple of SHT31 sensors I trimmed down. These fit just fine inside the shield without touching.
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Here are a couple of SHT31 sensors I trimmed down. These fit just fine inside the shield without touching.
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Nice!
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I used a pair of dikes to trim the board down. Takes about 5 minutes just don't cut through the circuit anywhere. I use silk I think its a 300 thread count to cover the full sensor as a filter.
Correction I'm using 100 count. 300 would also work I'm sure.
https://www.amazon.com/gp/product/B00JOYKV9I/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
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Here is the store but like I said check and make sure you are getting the updated version. I personally would wait for more testing.
https://www.allmeteo.com/meteo-shop/solar-radiation-shield-for-weather-station
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Here are a couple of SHT31 sensors I trimmed down. These fit just fine inside the shield without touching.
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What did you use to make it a “probe” without the sensor sliding out of the shield?
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Jan says they have been selling the new version since July.
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Sun reflection over snow I can report very good results today. 750 W/m2 solar and seeing no temperature increase inside the shield. It's running a few tenths under the FARS. Very good news indeed, the new Pro shield design change with added black and plastic composition is looking like a winner. Prior testing I was seeing 2F+ over snow.
I would still like to see an extended period of full sun at least an hour-long of 0-3 mph at anemometer height and check for heat buildup inside the shield for conclusive evidence but with snow reflection, I'm seeing virtually no warming of the sensor inside the shield.
In general, the PRO runs cooler daytime by about 1/2 degree vs Davis FARS with wind speeds in 8+ mph range. Sometimes it gets as much as .8 tenths cooler as wind speeds increase.
Here is 1:35 pm snapshot 700 W/m2 solar over snow with a 4 mph wind speed less at shield itself I'm sure.
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This may have gotten buried Jan is looking for a few more testers if anyone is setup to test if interested.
Hello, please also have a look at this Davis FARS vs MeteoShield Pro comparison. If anyone wants to test the new helical MeteoShield Pro, let us know. We will offer a number of users free shields for just shipping costs if they want to do and publish comparisons.
MeteoShield Pro vs. Davis FARS:
- https://www.wxforum.net/index.php?topic=34936.msg398911#msg398911 (https://www.wxforum.net/index.php?topic=34936.msg398911#msg398911)
- http://www.kwos.org/marinadimontemarciano/indexDesktop.php (http://www.kwos.org/marinadimontemarciano/indexDesktop.php) Sensirion sht30 in a BGT solar radiation shield compared to sht30 in a Meteoshield pro, next days the sht30 will be replaced by a state of the art sht35 sensor
- https://www.allmeteo.com (https://www.allmeteo.com/) USA distributor eshop run by COMPTUS (http://www.comptus.com/) who is the Made-in-USA manufacturer of the MeteoShield Pro
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This may have gotten buried Jan is looking for a few more testers if anyone is setup to test if interested.
Hello, please also have a look at this Davis FARS vs MeteoShield Pro comparison. If anyone wants to test the new helical MeteoShield Pro, let us know. We will offer a number of users free shields for just shipping costs if they want to do and publish comparisons.
MeteoShield Pro vs. Davis FARS:
- https://www.wxforum.net/index.php?topic=34936.msg398911#msg398911 (https://www.wxforum.net/index.php?topic=34936.msg398911#msg398911)
- http://www.kwos.org/marinadimontemarciano/indexDesktop.php (http://www.kwos.org/marinadimontemarciano/indexDesktop.php) Sensirion sht30 in a BGT solar radiation shield compared to sht30 in a Meteoshield pro, next days the sht30 will be replaced by a state of the art sht35 sensor
- https://www.allmeteo.com (https://www.allmeteo.com/) USA distributor eshop run by COMPTUS (http://www.comptus.com/) who is the Made-in-USA manufacturer of the MeteoShield Pro
I assume for comparison, one would need another sensor, a transmitter, and a console "like" devise to monitor both at once on different channels?
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Doing such test(s) assumes all the sensors are identical which is not a reality, there are always slight production variances...UNLESS all the sensors are quantified FIRST.
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Doing such test(s) assumes all the sensors are identical which is not a reality, there are always slight production variances.
You'd definitely have to do a side by first. When I was comparing 31's, I'd just stick two in the sensor chamber and merely switch between the two with my console in hand to see immediate results. Works very well.
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BEFORE actual usage, simply put all three sensors in a Styrofoam box and see what they individually read...repeat with COLD box (couple hours in freezer) and again with HOT box (wife/girlfriend's hair dryer). Plot all the results to show slope/intercept for each sensor. This is when an ENVOY8X is very handy.
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I use the Davis envoy 8x with up to 8 channels. JerryG I'm not sure what kind of setup he uses. As far as results go a tenth or two between sensors isn't that big of a deal when we are looking at FARS vs a passive shield where huge differences have occurred.
Having a desert climate tester would be great. Jerry is hampered by lots of wind & clouds, I have it a little better than Jerry with more sun and less wind but still not that many dead still periods except at night.
I wouldn't go to any extra expense if you don't already have the equipment unless you were planning on expanding and a passive shield was something you wanted to try. My goal is to switch over completely if testing continues to look good.
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I wouldn't go to any extra expense if you don't already have the equipment unless you were planning on expanding and a passive shield was something you wanted to try. My goal is to switch over completely if testing continues to look good.
Yeah, all I have is my lone VP2. I'd love to give it a whirl, but I'm of complete mindset anyway with the climate here, I'd stick with my case fan setup. Another reason I'd stick with my fan is bugs, never have a problem, too inhospitable. Can't go wrong there no matter what...as long as it's running.
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Well i need to put in my two cents worth, I am testing the new pro against the Davis fars and the Barani standard shield. All three are co-located on a tower in an open field over grass and the three sensors have compared to each other within a few tenths of a degree using a certified temperature meter accurate to +/- .3 degrees. The two passives shields are sht15's and the fars is a new sht31. The new pro has really been doing a great job in very light winds, but like Randy i am waiting for the long time calm wind and sunshine to reach a final result and the weather guys are predicting tomorrow to be calm to very light winds and sunny so should finally get the last conditions necessary to see how well the new pro really works. Now all i have to do is hope for once the weather guys are right :lol:.
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Here are a couple of SHT31 sensors I trimmed down. These fit just fine inside the shield without touching.
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What did you use to make it a “probe” without the sensor sliding out of the shield?
I just noticed this question sorry for the delay in answer. I use a piece of 1/4" pvc (hardware store) mounts through the opening with the sensor resting on. The mounting clamp holds the PVC so you can adjust sensor height depending on how long the pvc is.
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Unless I'm not seeing something, looks pretty good!
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I think so too. Little less wind would be nice. I forgot to add this was a sunny day Max solar hit 750 W/m2.
Update:
I removed the graph above because the 31 was reading low I discovered this after running a new sensor to the FARS shield.
I thought something was amiss because the FARS was running lower even at night so after changing the sensor confirmed. This means the PRO performed even better than indicated on the graph.
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The more the merrier :-)
I read about the Apogee ts100 use at some of the remote research stations, they are considered very good because of the low solar power needed for fan aspiration. I just couldn't figure out how to get the Davis sensor inside because of size.
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The more the merrier :-)
I read about the Apogee ts100 use at some of the remote research stations, they are considered very good because of the low solar power needed for fan aspiration. I just couldn't figure out how to get the Davis sensor inside because of size.
Thanks, I will not insert a davis sensor but a sht35 probe like this
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the dimension is correct for to insert in the Apogee ts100 port
sorry for my english
Mauro
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Still waiting for a sunny low less than 5 mph wind day. We had a very warm day for Feb. Here is what I'm seeing with the new Pro vs Davis FARS. Using 2 new sht-75 sensors matching. I didn't have the solar graphing the full day but you can see a few high thin clouds. Included the wind speed graph showing average wind speed. The reason I separated the graphs is for a better temperature graph with more detail.
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Not very good days, windy and few clouds, but this the result of today
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Bgt passive solar professional radiation shield with sensirion sht30 (yellow line)
Meteoshield pro wh31 with sensirion sht30 (blue line)
Meteoshield pro with external sht35 sensor (red line)
This the setup of Meteoshield, BGT has same height, same exposure, and 2,5 mt of distance
every sensors was tested and matched in range -10/+40° C
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Mauro
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Still, haven't had the dead still wind but yesterday before noon we had some sub 3 mph wind and saw little difference Pro vs FARS. The high and lows differences are within sensor error. Another peak solar day around 740 W/m2, unfortunately, the wind has been up during those peak solar periods.
mauro63 what shield is the BGT?
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I wish I had the time to read through this thread but I don't, so I'm just going to ask my question here:
How does the Barani MeteoShield Pro compare at night to the Davis FARS? Is it much less responsive to rapid cooling than the Davis FARS or not? I currently have a Davis DFARS and I'm thinking about replacing the shield with a Barani if it's more responsive at night (Davis DFARS can be over 1-1-1.5°C milder than a more responsive shield during rapid cooling) and roughly the same result by day.
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I am running my new pro instead of the fars, i find it more consistent in my readings and the new one has been doing real well with low wind speeds of 1 to 3 mph. I have not had a chance to see how it does in calm winds, i just don't get calm winds where i live for any good length of time. I might get calm for 10 to 20 minutes then the wind will pick up lightly and maybe go back to calm again. The main thing to consider is the Davis sensor will not fit in the shield without cutting it down to size or using an sht75 with a small filter. You can not use any sensor that will disrupt the airflow inside the shield, this will cause errors in the readings. I make up my own sensors to be as small as possible to overcome this problem.
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Still, haven't had the dead still wind but yesterday before noon we had some sub 3 mph wind and saw little difference Pro vs FARS. The high and lows differences are within sensor error. Another peak solar day around 740 W/m2, unfortunately, the wind has been up during those peak solar periods.
mauro63 what shield is the BGT?
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HI,
BGT is a professional Chinese solar radiation shield, not expensive and, after my first tests, not better than a commercial solar radiation shield like Davis 7714 or worse ;)
I think I will replace it tomorrow with a real professional passive solar radiation shield, Comet f8110
I have one of this shield, and I'm working to fix the sensor
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Mauro
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I am running my new pro instead of the fars, i find it more consistent in my readings and the new one has been doing real well with low wind speeds of 1 to 3 mph. I have not had a chance to see how it does in calm winds, i just don't get calm winds where i live for any good length of time. I might get calm for 10 to 20 minutes then the wind will pick up lightly and maybe go back to calm again. The main thing to consider is the Davis sensor will not fit in the shield without cutting it down to size or using an sht75 with a small filter. You can not use any sensor that will disrupt the airflow inside the shield, this will cause errors in the readings. I make up my own sensors to be as small as possible to overcome this problem.
So it's not an option then, that's a real shame. Barani itself seems to suggest otherwise though, your thoughts?
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https://www.baranidesign.com/faq-articles/2019/4/5/upgrading-davis-radiation-shield-with-helical-meteoshield-pro Here's the link
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You can make it fit but it has been found to disrupt the internal air circulation and you lose the advantage of the design of the shield. I have not tried putting a regular sensor in a pro but it might work better if you replace that big filter with the factory sf2 filter which just fits the sht31 sensor, that would remove a lot of blockage. I have a new 31 that i have been thinking about cutting down in size, it has the sf2 filter on it, i might just try it in the shield before i reduce the size of it to see how it responds, could be interesting to try.
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You can make it fit but it has been found to disrupt the internal air circulation and you lose the advantage of the design of the shield. I have not tried putting a regular sensor in a pro but it might work better if you replace that big filter with the factory sf2 filter which just fits the sht31 sensor, that would remove a lot of blockage. I have a new 31 that i have been thinking about cutting down in size, it has the sf2 filter on it, i might just try it in the shield before i reduce the size of it to see how it responds, could be interesting to try.
I agree, but, believe me, meteoshield pro performances are very good also with a big sensor
I'm testing two meteoshield pro, in one of them there is a sht35 probe with 25mm diameter, the other with ecowitt wh31, sensirion sht30 in standard version
today results, comparing to bgt solar radiation shied
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sorry for my poor english
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Ok i took one for the team and voided the warranty on my new 31. I cut the goop off of the cable so i could fold it over like in the instructions and i did not do anything to the board itself. I am using the small factory filter is the only thing different. Now i will compare it to the other readings i got with the small sensor and it will really show up when the wind gets real low if it had any bad affects on the readings.
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Yeah, mauro63 I wouldn't bother testing the BTG. Rather see the 7714 in the test.
Jasper3012 the thread has evolved to the newer Meteoshield pro. They added more black material for reflection and changed the plastic composition with the new version. From what I can tell it runs very close to the Davis FARS without the headache of fan and solar panel. Bugs will get into these shields however the FARS tend to keep them away.
Still inconclusive how the New PRO does in dead air over time say 30+ minutes vs FARS. From what I'm seeing with 1-2 mph breeze it looks good vs FARS.
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Still inconclusive how the New PRO does in dead air over time say 30+ minutes vs FARS. From what I'm seeing with 1-2 mph breeze it looks good vs FARS.
Would it be reasonably possible to bring both shields inside and put something like flood or spot light on the two? You certainly could get calm wind inside. Maybe even a fan way back to simulate a light breeze as well if you wanted.
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Still inconclusive how the New PRO does in dead air over time say 30+ minutes vs FARS. From what I'm seeing with 1-2 mph breeze it looks good vs FARS.
Would it be reasonably possible to bring both shields inside and put something like flood or spot light on the two? You certainly could get calm wind inside. Maybe even a fan way back to simulate a light breeze as well if you wanted.
Never really thought of it. Probably not though because the flood lamp being even slightly off-axis would build more heat on one shield vs the other. I'll just wait for mother nature. :-)
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Yeah, mauro63 I wouldn't bother testing the BTG. Rather see the 7714 in the test.
Jasper3012 the thread has evolved to the newer Meteoshield pro. They added more black material for reflection and changed the plastic composition with the new version. From what I can tell it runs very close to the Davis FARS without the headache of fan and solar panel. Bugs will get into these shields however the FARS tend to keep them away.
Still inconclusive how the New PRO does in dead air over time say 30+ minutes vs FARS. From what I'm seeing with 1-2 mph breeze it looks good vs FARS.
Yeah, that's the main thing I want to know, how responsive it is vs FARS in calm conditions at night. That's the reason I might be replacing the Davis DFARS, since it lags behind considerably vs the smaller and more responsive shields of the Vantage Vue & Alecto WS-5500 at night.
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Still inconclusive how the New PRO does in dead air over time say 30+ minutes vs FARS. From what I'm seeing with 1-2 mph breeze it looks good vs FARS.
Would it be reasonably possible to bring both shields inside and put something like flood or spot light on the two? You certainly could get calm wind inside. Maybe even a fan way back to simulate a light breeze as well if you wanted.
Never really thought of it. Probably not though because the flood lamp being even slightly off-axis would build more heat on one shield vs the other. I'll just wait for mother nature. :-)
Oh well. Maybe if you get bored, it'd probably be fun to try..
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The performance of the pro compared to the fars at night has been nearly the same, we do get calm winds here at night. I haven't seen any of the cooling effects at night like a lot of passives get. Right now the pro and the fars are reading the same temperature but we are cloudy so no sun to do any heating.
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The performance of the pro compared to the fars at night has been nearly the same, we do get calm winds here at night. I haven't seen any of the cooling effects at night like a lot of passives get. Right now the pro and the fars are reading the same temperature but we are cloudy so no sun to do any heating.
Pleased to hear that, should be a lot more responsive than the Davis DFARS. Now that we're approaching the warm season I likely won't get the Barani for the time being, as tmin is not as important to me as it is in winter. I'll likely get it in the autumn to more accurately record temps during a cold night.
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Got any data to report yet @jerryg? Curious to see.
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Got a lot of data but still waiting for a sunny calm day which is near impossible where i live. I have been comparing the pro with both the Davis and Young fars and the pro has been doing real well, running around .5 to 1 degree cooler during the heat of the day and all three read the same at night or on cloudy days. The pro does really well above 3 mph and in the calm to 2 mph runs about the same as the fars, so seems to be an improvement on the low wind readings. I just swapped out the sensors between the pro and the Young to verify that i get the same results with the readings. I am still real happy with the pro and i did do the modification on the 31 sensor and it fits the pro ok and i did not see any real difference with the readings but i did go ahead a cut the size of the board down to allow for better air flow but i have not noticed it made any difference.
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So it's not necessary to cut down on the Davis SHT-31 sensor for improved accuracy? Does it fit with the white filter too?
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I don't know about that i never use the Davis filter i always use the factory filter or a homemade one. The smaller the filter the better the response time. I like as much air flow as possible.
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What do you mean with "the factory filter"? I currently use this, I'm guessing that won't fit in the MeteoShield Pro ](*,)
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I think it does fit with the original filter, all you have to do is cut the goop that holds the cable down on the board so you can fold the cable over. There is a link a few post back about how to do it. One thing i did try and it works, you can mount the pro right underneath the iss mount just like the Davis shield was mounted with a little space between the top of the pro and the base and the cable will just reach inside the iss and plug in. One thing i did and it works fine is i cut the filter material of the Davis filter into a square piece that just covered the sensor and held in in place with a small amount of rope putty that i have had for a long time so no out gassing problems and it worked just fine. The sf2 filter works real well and i used the putty to hold it in place.
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You mean that you put the Pro right under the Davis rain gauge, where the Davis shield was?
Wrt to the temp sensor, does the original filter cause the slower response time or is it mostly the design of the Davis shield? I'm interested to know whether the response time would be faster if I remove/redo the filter cap but still have the sensor in the Davis shield.
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I'm also going to attempt to cut some of the green plastic or whatever it is to reduce the mass of the sensor, should help aswell. If I'm still not seeing the response time I want I'll probably end up buying the MeteoShield Basic or Pro. Not sure whether there's a great difference between the Basic and the Pro, atm I'm leaning toward the Pro.
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The idea of the factory filter is it fits right over the sensor and has very little air space to moisten up and that lets the sensor respond faster than the big one which has a lot of air space inside that has to be filled up and that takes time and slows down the sensor response to changes. Yes i put it right under the base just like the factory shield to let the cable reach. When i cut mine down i put a longer cable on it so i could move the shield around. You could lengthen the cable with a cat splice and a short six wire telephone cable you can get at electronic stores but you will probably have to redo one connector because most of them are not straight thru but are mirrored connections. All kinds of things can be done with the sensor. The sensor only uses four wires in slots 1,2,3 and 6 so two are not connected on the board so you can just use a straight 6 wire setup as long as it is straight thru.
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The idea of the factory filter is it fits right over the sensor and has very little air space to moisten up and that lets the sensor respond faster than the big one which has a lot of air space inside that has to be filled up and that takes time and slows down the sensor response to changes.
What OEM filter is not the "big one"?
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this is my vp2 sensor modded to fit into Barani Meteoshield pro
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Mauro
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I removed the filter cap and put some of it on top of the sensor, secured with tape. I'll see if it's more responsive, should be unless the tape messes with it. How did you get the black part connecting the cable and the green part off, Mauro? It seems very strongly attached, tried to get it off but couldn't.
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I removed the filter cap and put some of it on top of the sensor, secured with tape. I'll see if it's more responsive, should be unless the tape messes with it. How did you get the black part connecting the cable and the green part off, Mauro? It seems very strongly attached, tried to get it off but couldn't.
I will try to explain but, forgive me for my horrible English ;(
In my case, my original sht31 sensor was covered with a very strong by a semi-trasparent glue, impossible to remove with fingers
so, using a very tiny cutter, with great patience and attention, I've removed all the glue part non necessary so to have cable free
Mauro
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I see. Have you thought of removing the filter cap and using something smaller as filter? Your sensor wil become even more responsive then.
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Do you have to reorientate the cable so it's parallel to the long side of the green part to make it fit, or can you just remove the strain relief and bend the cable downwards and out of the MeteoShield Pro via the bottom? [ You are not allowed to view attachments ]
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Picture of the new filter I made
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Do you have to reorientate the cable so it's parallel to the long side of the green part to make it fit, or can you just remove the strain relief and bend the cable downwards and out of the MeteoShield Pro via the bottom? [ You are not allowed to view attachments ]
No, it's not enough remove the strain relief and bend the cable, the risk is to damage the cable
this is the final result
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Mauro
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Looks good... How did you get the strain relief (encircled part) off the cable? [ You are not allowed to view attachments ]
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Looks good... How did you get the strain relief (encircled part) off the cable? [ You are not allowed to view attachments ]
simply with same cutter
gently cut the longest part on both sides, at this point, you will remove the rest with your fingers
pay a lot of attention when you remove the glue on the pcb part, the risk is to damage the cable
Mauro
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I have done some work and cut the strain relief up to where you can see the end of the cable. Do you think this is sufficient to fit inside the MeteoShield Mauro/Jerry? [ You are not allowed to view attachments ]
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It might be ok but i took mine down to the wires so it could fold over in line with the board and i removed the excess goop down towards the edge and it leaves some holes which is perfect for a small zip tie or wire to make a strain relief for the cable. With the cable in line with the board it lets the cable center in a piece of tubing to hold the sensor in place at the right height.
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I see, so you did the exact same thing as Mauro did. I might buy it sooner than first thought, so I'm going to have to make a choice between the MeteoShield Pro or Basic. Do you know if there's a big difference in performance between the two shields, and if so in what situation is this most notable (for example during snow cover or lights)?
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Well that's a hard thing to put a finger on, i like the standard shield and the performance was pretty good but it was much improved by taking the shield apart and painting the inside of the pieces black, made a noticeable difference in performance. It comes apart in a whole bunch of little pieces that have to be put back together like a jug saw puzzle. Once you see how they are stacked it is not too tough to do. I prefered the painted standard over the old pro but the new pro with the improvements has been working real well even down in the 1 to 2 mph range, just a little air movement and it is fine but i have not had a calm sunny day down here in south texas, no snow for sure, and i my area it works just fine. Now how it will work in an area that gets a lot of calm sunny days is for someone else to try out. I have found out a lot of interesting things when comparing the pro to two different fars,, one is the Davis and the other is the R.M. Young. I might have to make up a new topic down the road after i nail down all the little things that the fars shields fall short in.
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Hi, I want to update my cover Davis daytime soon. I wonder whether to buy FARS or Barani Pro? Both covers have their pros and cons. A passionate choice. I ask for advice. I am currently using 7714 and it's ok but summer ahead of me which can be hot.
Sorry for my english i use google traslate.
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Well i really don't want to give advice because each location is different and might have different needs. If you are in a location that has some wind most of the time then the pro might be the one for you. I like not having to deal with any kind of power and fans. I am waiting for someone to get a good long calm day with sunshine to really see if and how much the temperature will go up. I sort of have a figure of one degree or less but because we just don't get calm winds for any length of time a few bumps every so often will not be a deal killer. I have to keep reminding myself that this is just my hobby and not to get too nerdy about things :lol:. I will tell you the fan in the Davis shield is to weak on airflow and has errors when the wind is blowing pretty good. I put a stronger fan in the shield and solved that problem.
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Meteoshield standard (or basic) is out of stock and will not build in the future, so only new pro will remain
My personal experience with Meteoshield basic is good, but not better than a davis 7714, or a little more better
as you can see
the green line is a Vernon globe thermometer
Mauro
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Hi, I want to update my cover Davis daytime soon. I wonder whether to buy FARS or Barani Pro? Both covers have their pros and cons. A passionate choice. I ask for advice. I am currently using 7714 and it's ok but summer ahead of me which can be hot.
Sorry for my english i use google traslate.
personally I try, as far as possible, to avoid ventilated screens, the problems they can present are often greater than the advantages they can give
poor reliability, unusability in case of malfunction, underestimation of temperatures in certain conditions etc
I only had good results with apogee ts100, one of the few ventilated units that can work well even with the fan stopped thanks to the excellent design and the correct use of the Venturi effect
personally, at the moment, I'm not going to replace the barani pro as my reference solar radiation shield
Mauro
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On the Barani website it says that the big version of the Pro can fit sensors to 25 mm diameter, but the Davis sensor is more than that? Doesn't make a whole lot of sense?
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On the Barani website it says that the big version of the Pro can fit sensors to 25 mm diameter, but the Davis sensor is more than that? Doesn't make a whole lot of sense?
sorry, probably, given my difficulty with English, I can't guess the meaning of the question
the barani meteoshield pro gives its best with modest-sized probes, the better if the sensor has a cylindrical shape, even better
however, the davis base, vertically, fits perfectly, still allowing good air circulation
the basic rule, however, speaking of sensors, is "the smaller the better" ;)
Mauro
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Today's results
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Mauro
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They say that the MeteoShield Pro allows sensors up to 25 mm diameter, but the Davis SHT31 sensor is more than 25 mm so you wouldn't expect it to fit in.
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They say that the MeteoShield Pro allows sensors up to 25 mm diameter, but the Davis SHT31 sensor is more than 25 mm so you wouldn't expect it to fit in.
what can I say?
I have Meteoshield pro, I have the modified sht31 davis original sensor in my hand ;)
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Mauro
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Can you confirm which size of the MeteoShield Pro you bought? There's 2 different sizes, I'm guessing you got the big one.
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Can you confirm which size of the MeteoShield Pro you bought? There's 2 different sizes, I'm guessing you got the big one.
There's no difference on the internal chamber
the sizes option regard only the connector on the inferior plate, obviously, the size of the plastic tube that you need to will use depend by the size of connector you will choose
Mauro
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I see, I don't see the point in spending the extra 30 euros then to get the bigger connector, I can just get a smaller tube
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I see, I don't see the point in spending the extra 30 euros then to get the bigger connector, I can just get a smaller tube
Of course, in this case is not useful to spend more money
the choose become important if you use a complete probe, in this case you have to consider the probe dimension, Vaisala, Campbell, Delta-Ohm, Rotronic etc probes could have different dimension
Mauro
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Well I don't think there's a probe out there that measures temperature/humidity and is compatible with the Davis transmitters, I know Davis have a temperature probe but it doesn't measure humidity so that's not an option
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Well I don't think there's a probe out there that measures temperature/humidity and is compatible with the Davis transmitters, I know Davis have a temperature probe but it doesn't measure humidity so that's not an option
No, there is'nt, my approach was as a general, not regarding only Davis vp2 option
as I know, there's no at the moment a t/rh probe that can be directly connected to vp2 iss trasmitter
for example, I'm using in one of my Meteoshield Pro a modified version of Ecowitt wh31 sensor with an external sht35 probe
Mauro
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Yep I understand, I'd be interested in testing out different probes too but I don't want to go bankrupt. :lol: I edited the Davis sensor yesterday so it's now similar to what you have, with the cable bent in line with the long side of the sensor and secured with a ziptie through those 2 holes that I uncovered with a cutter. Now I only need to order the MeteoShield Pro and I'll be good to go.
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Yep I understand, I'd be interested in testing out different probes too but I don't want to go bankrupt. :lol: I edited the Davis sensor yesterday so it's now similar to what you have, with the cable bent in line with the long side of the sensor and secured with a ziptie through those 2 holes that I uncovered with a cutter. Now I only need to order the MeteoShield Pro and I'll be good to go.
well done, have a good tests ;)
Mauro
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Major breakthrough today. I can announce under light wind strong solar the PRO shield does better handling snow reflection vs the Davis FARS. So changes made with the new PRO shield design helped substantially. The previous test from last winter the PRO failed this very test (+2f) and now is actually better (-1f) vs the FARS. I'm testing with 2-SHT75's temperature sensors.
The test kills 2 birds with 1 stone low wind test and snowfield test.
Current snapshot showing 0 wind and solar strength.
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Graph so far today
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Image of snow cover
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Update at 1pm the two sensors have came together still no wind.
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Still looking great for the Pro shield strong solar and very little wind.
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As we get a later in the day the FARS is trending slightly lower by a few tenths but still excellent passive shield performance over snow.
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Very good performance, I ordered it 2 days ago [tup]
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Very impressive results for non-FARS setup.
tweatherman
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Final graph with excellent test conditions. The Pro did have a spell 10 minutes where it stayed about +1.2 F vs Fars. High temps came in Pro 24.7F, Fars 24.4F so very close .3 tenths.
Wind stayed low all day less than 3 mph usually 0-1 mph. Solar was stong in the 850 range.
Summary:
The Pro always outperforms the Fars with wind this was under still conditions. 0-3 mph wind speeds and full solar over a snowfield.
Overall I would say excellent performance for a passive shield it read lower than the FARS during the warmup period of the day and higher during a short afternoon period no doubt the best passive I've tested. Seriously thinking of using this shield as the main unit going forward. No more messing with fans and solar panels.
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Final graph with excellent test conditions. The Pro did have a spell 10 minutes where it stayed about +1.2 F vs Fars. High temps came in Pro 23.7F, Fars 23.4F so very close .3 tenths.
Wind stayed low all day less than 3 mph usually 0-1 mph. Solar was stong in the 850 range.
Summary:
The Pro always outperforms the Fars with wind this was under still conditions. 0-3 mph wind speeds and full solar over a snowfield.
Overall I would say excellent performance for a passive shield it read lower than the FARS during the warmup period of the day and higher during a short afternoon period no doubt the best passive I've tested. Seriously thinking of using this shield as the main unit going forward. No more messing with fans and solar panels.
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Many compliments for test and for results
I have same opinion, the Pro is the only passive screen able to compete with a FARS, with fewer risks about temperature underestimation in specific conditions due to the fact that the normal FARS has not the ability to have control of the ventilation in different conditions and also for much more reliability.
With the right sensor is surely the best reference passive solar radiation shield on the market
Mauro
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Thought this was interesting here is the Barani Standard version (painted black inside) under same conditions yesterday also using SHT75 but at a different location 1/2 mile away. Notice how much higher the temperature peaked 27.5F vs 24.4 so +3 degrees. This was what I was seeing over a snowfield when I tested last year's Pro model. The new design I'm convinced has minimized the snow reflection while the Standard version as you can see still suffers under certain conditions.
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The Pro over snow yesterday you don't get the 3-degree F spike.
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Thought this was interesting here is the Barani Standard version (painted black inside) under same conditions yesterday also using SHT75 but at a different location 1/2 mile away. Notice how much higher the temperature peaked 27.5F vs 23.4 so +4 degrees. This was what I was seeing over a snowfield when I tested last year's Pro model. The new design I'm convinced has minimized the snow reflection while the Standard version as you can see still suffers under certain conditions.
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The Pro over snow yesterday
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I see, and I agree, I have the Meteoshield standard in my field test, at about 2,5 mt of distance from Meteoshield pro, and also without snow cover, the most difficult situation for a solar radiation shield due to reflected solar radiation, the limits are evident
Mauro
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I've seen enough with the new Pro shield so it's going in service as the main radiation shield. I'm doing one more test that has nothing to do with the Pro performance by raising the sensor height to 80" (inches) above the ground to avoid the sprinklers this summer. I want to do some overnight low-temperature comparisons against the 5' (foot) Fars to see if the 2 extra feet height make a large enough difference.
I'll probably move back down to 5' shield height after sprinklers are off next fall.
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That will be interesting to compare. I have a bit of a random question, do you remember how long it took them to get the MeteoShield Pro delivered to your house? I ordered mine 3 days ago and am wondering when I should be expecting it. I guess it varies per country (plus the corona crisis now) but maybe it can give me an idea.
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Not sure when they actually shipped, I was a tester for the shield last year and was asked if I would test the latest design. Seems like it showed up about a week around 7 days later.
My testing from last year contributed to the design change reducing the snowfield light reflection.
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Thanks for that. ;) Although in Belgium we don't get much snow at all so I'm afraid it won't benefit me too much. ](*,)
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Although in Belgium we don't get much snow at all so I'm afraid it won't benefit me too much.
I hope you do the shield comparison. I'm really waiting for the comparison between Barani Pro and Davis 7714. Maybe someone will do a test? :grin:
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Although in Belgium we don't get much snow at all so I'm afraid it won't benefit me too much.
I hope you do the shield comparison. I'm really waiting for the comparison between Barani Pro and Davis 7714. Maybe someone will do a test? :grin:
I thought mauro63 was going to test it. I do have a 7714 somewhere but its a modified version painted black interior to reduce reflection so not manufacture stock.
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Thanks for that. ;) Although in Belgium we don't get much snow at all so I'm afraid it won't benefit me too much. ](*,)
Well, the test above confirmed both low wind and snow performance. As far as the shield goes when the wind blows the Pro is always doing better vs FARS. I'll post today's performance so you can see what I'm talking about. Take into the fact the PRO is now at 80" vs 62"
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Here is the full day sunny solar peaked at 840 Wm2
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MeteoShield has been running for 2 days now, it's installed at 1,5 m below and to the left of the Davis rain collector. I'm only able to compare it to the WS-2902, but here are the results for first two days:
Day 1 tmax
Pro 12.3°C
WS-2902 13.4°C
Day 2 tmin
Pro 3.0°C
WS-2902 2.6°C
Day 2 tmax
Pro 12.5°C
WS-2902 13.2°C
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The daytime performance is, as expected, solid. Day 2 had slightly more wind than day 1, which explains the slightly smaller difference between the two shields. Both days were completely sunny.
The Pro is much more responsive at night than the Davis standard shield, but still lags 0.2-0.4°C behind the WS-2902. That's probably down to the fact the Davis T/H sensor is much larger and therefore takes more time to cool than the WS-2902 T/H sensor.
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The Barani's cover is placed in such a way that a shadow falls on it from the Davis rain gauge in the afternoon. It's best to put the cover in full sun all the time.
I follow the page myself where the readings from Barani and Davis daytime are compared. The results are interesting. Often there are no differences in readings.
Barani Pro - http://www.mcmeteorimini.altervista.org/template/indexDesktop.php (http://www.mcmeteorimini.altervista.org/template/indexDesktop.php)
Davis daytime - http://mcmeteo.altervista.org/template/indexDesktop.php (http://mcmeteo.altervista.org/template/indexDesktop.php)
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Do you have a reason as to why it should be in full sun? The cable for the Davis T/H sensor is very short so I have limited options. I could place the shield next to the Davis rain gauge but then that'll will be blocking off airflow into the shield.
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Do you have a reason as to why it should be in full sun?
WMO Standards:
In order to achieve representative results when comparing thermometer readings at different
places and at different times, a standardized exposure of the screen and, hence, of the
thermometer itself is also indispensable. For general meteorological work, the observed air
temperature should be representative of the free air conditions surrounding the station over as
large an area as possible, at a height of between 1.25 and 2 m above ground level. The height
above ground level is specified because large vertical temperature gradients may exist in the
lowest layers of the atmosphere. The best site for the measurements is, therefore, over level
ground, freely exposed to sunshine and wind and not shielded by, or close to, trees, buildings
and other obstructions. Sites on steep slopes or in hollows are subject to exceptional conditions
and should be avoided. In towns and cities, local peculiarities are expected to be more marked
than in rural districts. Temperature observations on the top of buildings are of doubtful
significance and use because of the variable vertical temperature gradient and the effect of the
building itself on the temperature distribution.
Source: Measurement of temperature - WMO Library (https://library.wmo.int/doc_num.php?explnum_id=3149)
Personally, I try to follow these recommendations and place my sensors in the sunniest areas of the plot with free air flow.
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Do you have a reason as to why it should be in full sun?
WMO Standards:
In order to achieve representative results when comparing thermometer readings at different
places and at different times, a standardized exposure of the screen and, hence, of the
thermometer itself is also indispensable. For general meteorological work, the observed air
temperature should be representative of the free air conditions surrounding the station over as
large an area as possible, at a height of between 1.25 and 2 m above ground level. The height
above ground level is specified because large vertical temperature gradients may exist in the
lowest layers of the atmosphere. The best site for the measurements is, therefore, over level
ground, freely exposed to sunshine and wind and not shielded by, or close to, trees, buildings
and other obstructions. Sites on steep slopes or in hollows are subject to exceptional conditions
and should be avoided. In towns and cities, local peculiarities are expected to be more marked
than in rural districts. Temperature observations on the top of buildings are of doubtful
significance and use because of the variable vertical temperature gradient and the effect of the
building itself on the temperature distribution.
Source: Measurement of temperature - WMO Library (https://library.wmo.int/doc_num.php?explnum_id=3149)
Personally, I try to follow these recommendations and place my sensors in the sunniest areas of the plot with free air flow.
I agree, In this case, no Davis Vantage pro, even if perfectly installed, complies with WMO regulations
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we have to distinguish the shade of a screen according to the different scenarios:
- if the screen is in the shade for short periods, provided that this shadow concerns only the screen, and not the ground below, this is irrelevant for the purposes of a meteorological survey
- if instead, we talked about a comparison of performances between different shields, also in this case shading is not a problem, provided that all the screens under test enjoy the same shading and at the same moments, therefore they are always in the same conditions
Mauro
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The ground below and the surrounding plot is in full sunshine, so it should be representative. The WS-2902 shield I'm comparing to is also largely shaded by the rain gauge above it, so both shields are under similar conditions.
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Speaking of those WMO guidelines I moved the FARS to the backyard and run a steady +2F over the PRO shield in the open front yard.
I'll attach an image where it's mounted at 7'. The yard as you can see is rather large but the trees and fence cause a heat island of sorts. The front location is much more open even if by an asphalt road its the better location.
So having free airflow is very important when setting up a weather station.
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That's why I placed it below the Davis rain gauge and not next to it, so the airflow isn't hampered. It seems a waste to buy the MeteoShield if I'm going to place it somewhere with restricted airflow.
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Yes from what I've learned good airflow is the #1 objective for accurate temperatures. This is why its challenging to find a good location that meets all needs in residential neighborhoods.
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I wanted to make a new thread but figured I'll ask it in here; is there a notable difference in max/min temp between (dry) bare soil and grass? The Pro has been running between 0.0-0.5 milder than the WS-2902 at night but it's located above grass, while the WS-2902 above bare soil. The grass extends like 2 meters on 3 sides of the Pro, with bare soil surrounding it on 3 sides and grass on the other.
I assume under windy conditions there's not much of a difference since the air is mixed about, but could this be a factor under calm conditions with strong cooling/heating?
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Today results, good solar radiation and, in the second part of the day, with low wind speed
Mauro
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Very good performance yet again. I must say I've been impressed by the MeteoShield Pro since it's been in use, definitely think it's the best passive shield out there. Another pic of my setup below.
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In a few days we will start a comparison between
:arrow: Davis 7714 passive
:arrow: Davis 7714 with powerful fan
:arrow: Barani meteohelix
Maybe with SHT30 sensirion sensor in the Davis and SHT35 in barani...
If we succeed, we will make the comparison equipping the davis 7714 with a SHT35 with probe.
Here the Davis 7714 that will use in passive mode and with fun
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I've seen enough with the new Pro shield so it's going in service as the main radiation shield. I'm doing one more test that has nothing to do with the Pro performance by raising the sensor height to 80" (inches) above the ground to avoid the sprinklers this summer. I want to do some overnight low-temperature comparisons against the 5' (foot) Fars to see if the 2 extra feet height make a large enough difference.
I'll probably move back down to 5' shield height after sprinklers are off next fall.
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Yuor radiation shield is cover on the top?
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I've seen enough with the new Pro shield so it's going in service as the main radiation shield. I'm doing one more test that has nothing to do with the Pro performance by raising the sensor height to 80" (inches) above the ground to avoid the sprinklers this summer. I want to do some overnight low-temperature comparisons against the 5' (foot) Fars to see if the 2 extra feet height make a large enough difference.
I'll probably move back down to 5' shield height after sprinklers are off next fall.
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Yuor radiation shield is cover on the top?
Don't understand the question, sorry.
Glad to see the 7714 test. So how do you keep the fan from getting wet?
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I've seen enough with the new Pro shield so it's going in service as the main radiation shield. I'm doing one more test that has nothing to do with the Pro performance by raising the sensor height to 80" (inches) above the ground to avoid the sprinklers this summer. I want to do some overnight low-temperature comparisons against the 5' (foot) Fars to see if the 2 extra feet height make a large enough difference.
I'll probably move back down to 5' shield height after sprinklers are off next fall.
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Yuor radiation shield is cover on the top?
Don't understand the question, sorry.
Glad to see the 7714 test. So how do you keep the fan from getting wet?
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If the fans exposed on the bottom it will still get wet.
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If the fans exposed on the bottom it will still get wet.
it's very very hard that the fun cab be wet...but...only the time of the test, than only metehelix remain working
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In a few days we will start a comparison between
:arrow: Davis 7714 passive
:arrow: Davis 7714 with powerful fan
:arrow: Barani meteohelix
Cool! I look forward to the results.
From my comparison of Davis daytime and Davis 7714 passive covers, I can write that the difference is 0.2C on average in favor of daytime. Soon I will be testing Davis daytime with a 12V fan.
(http://pogodarybnik.pl/obrazki/Davis daytime 12v fan.jpg)
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In a few days we will start a comparison between
:arrow: Davis 7714 passive
:arrow: Davis 7714 with powerful fan
:arrow: Barani meteohelix
Cool! I look forward to the results.
From my comparison of Davis daytime and Davis 7714 passive covers, I can write that the difference is 0.2C on average in favor of daytime. Soon I will be testing Davis daytime with a 12V fan.
(http://pogodarybnik.pl/obrazki/Davis daytime 12v fan.jpg)
0.2 in the average temperature ore in the max th?
it'seems a little difference between daytime and 7714
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Although in Belgium we don't get much snow at all so I'm afraid it won't benefit me too much.
I hope you do the shield comparison. I'm really waiting for the comparison between Barani Pro and Davis 7714. Maybe someone will do a test? :grin:
I will please you 8-)
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0.2 in the average temperature ore in the max th?
it'seems a little difference between daytime and 7714
Of course it was about Tmax. Sorry. The differences are really negligible. Currently, my main radiation shield is ... 7714.
I will please you 8-)
Yes, it will be great. \:D/
I will see if it is worth investing in a shield Barani Pro.
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I've seen enough with the new Pro shield so it's going in service as the main radiation shield. I'm doing one more test that has nothing to do with the Pro performance by raising the sensor height to 80" (inches) above the ground to avoid the sprinklers this summer. I want to do some overnight low-temperature comparisons against the 5' (foot) Fars to see if the 2 extra feet height make a large enough difference.
I'll probably move back down to 5' shield height after sprinklers are off next fall.
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Yuor radiation shield is cover on the top?
Don't understand the question, sorry.
Glad to see the 7714 test. So how do you keep the fan from getting wet?
Which way does the air flow? Is it pulling from the top down or pushing the air up?
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I've seen enough with the new Pro shield so it's going in service as the main radiation shield. I'm doing one more test that has nothing to do with the Pro performance by raising the sensor height to 80" (inches) above the ground to avoid the sprinklers this summer. I want to do some overnight low-temperature comparisons against the 5' (foot) Fars to see if the 2 extra feet height make a large enough difference.
I'll probably move back down to 5' shield height after sprinklers are off next fall.
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Yuor radiation shield is cover on the top?
Don't understand the question, sorry.
Glad to see the 7714 test. So how do you keep the fan from getting wet?
Which way does the air flow? Is it pulling from the top down or pushing the air up?
pushing the air up from the out
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I've seen enough with the new Pro shield so it's going in service as the main radiation shield. I'm doing one more test that has nothing to do with the Pro performance by raising the sensor height to 80" (inches) above the ground to avoid the sprinklers this summer. I want to do some overnight low-temperature comparisons against the 5' (foot) Fars to see if the 2 extra feet height make a large enough difference.
I'll probably move back down to 5' shield height after sprinklers are off next fall.
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Yuor radiation shield is cover on the top?
Don't understand the question, sorry.
Glad to see the 7714 test. So how do you keep the fan from getting wet?
Which way does the air flow? Is it pulling from the top down or pushing the air up?
pushing the air up from the out
I think you mean up and out the top. If so, any heat the fan motor may generate will be immediately picked up by the sensor. Personally, I'd turn it around just to be safe, if you can, and still make it "aspirate" properly.
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I've seen enough with the new Pro shield so it's going in service as the main radiation shield. I'm doing one more test that has nothing to do with the Pro performance by raising the sensor height to 80" (inches) above the ground to avoid the sprinklers this summer. I want to do some overnight low-temperature comparisons against the 5' (foot) Fars to see if the 2 extra feet height make a large enough difference.
I'll probably move back down to 5' shield height after sprinklers are off next fall.
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Yuor radiation shield is cover on the top?
Don't understand the question, sorry.
Glad to see the 7714 test. So how do you keep the fan from getting wet?
Which way does the air flow? Is it pulling from the top down or pushing the air up?
the problem of the davis 7714 (that remain one of the best passive radiation shield in the word) is:
Solar radiation should not be understood only from top to bottom. Solar radiation is from all directions, indirect and direct. The plates of the Davis 7714 are affected not only from above and from the side, but also in their lower part.
Barani, who obviously has a recent project in Davis, understood this by taking advantage of the evidence and knowledge of those who preceded him.
And what did he do?
Practically, in addition to a very well-made helical screen that takes full advantage of the Venturi effect, the sensor has incorporated it into a completely dark room, which receives no light anywhere. In addition, the black parts well arranged along the whole screen internally, allow the screen to block the heat by diffusion and indirect radiation. It does not allow sunlight and heat to pass through it into the inner chamber. That's all...
Davis 7714 has too much space between the plates and lacks the black part. The fan gives the screen a little help, in my case, sometimes even counterproductive perhaps. [ You are not allowed to view attachments ]
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You're missing my point, nothing to do with the sun and solar insolation. I'm saying that any heat generated by the fan's motor is being "pushed" into the sensor chamber and "measured" by the sensor. All aspirated shields have the fan on top and air sucked in from the bottom so the air remains ambient, unaffected by any heat from the motor.
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Yes all FARS draw air across sensor and exhaust out the top. The heat from fan, especially in cold weather, could be an issue otherwise.
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What a great design. No wonder the VP2's 24hr shield is patented.
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Yes all FARS draw air across sensor and exhaust out the top. The heat from fan, especially in cold weather, could be an issue otherwise.
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With my fun Irrelevant. There are not electronic parts exposed.
In Davis H24 fan sensor is into a tube...
In Davis 7714, the air get into the radiation Shield from every space..
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You're missing my point, nothing to do with the sun and solar insolation. I'm saying that any heat generated by the fan's motor is being "pushed" into the sensor chamber and "measured" by the sensor. All aspirated shields have the fan on top and air sucked in from the bottom so the air remains ambient, unaffected by any heat from the motor.
While, sucking in air from above, all the heat present in the plates and between the plates of the screen, heats the air that reaches the fan, heating the internal chamber.
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Never mind.
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Never mind.
???
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While, sucking in air from above, all the heat present in the plates and between the plates of the screen, heats the air that reaches the fan, heating the internal chamber.
It seems as if you're saying that as heat is removed from the shield it gets hotter, which kind of goes against the laws of thermodynamics.
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While, sucking in air from above, all the heat present in the plates and between the plates of the screen, heats the air that reaches the fan, heating the internal chamber.
It seems as if you're saying that as heat is removed from the shield it gets hotter, which kind of goes against the laws of thermodynamics.
I believe it needs to take air from outside, that is from outside the screen, then let the air enter the inner chamber and then let it out.
We can do 3 tests:
:arrow: davis 7714 with fan off
:arrow: davis 7714 with fan that sucks air from outside
:arrow: Davis 7714 with fun that takes air from the inner chamber and pushes it out
no problem for me
my goal is to share with you the difference between a Davis 7714 screen and a barani meteoshield pro screen
i want to say that for meIt is clear that the best screen that Davis produces is the 7714..no doubt
5-plate screens and 5-plate screens + daytime are all worse than 7714
Davis benefits to the rain gauge, to the PCBA that make shade on the screen. Otherwise, without this two part there would be embarrassing temperature overestimations.
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We can do 3 tests:
:arrow: davis 7714 with fan off
:arrow: davis 7714 with fan that sucks air from outside
:arrow: Davis 7714 with fun that takes air from the inner chamber and pushes it out
2 - with fan that sucks air from outside - it sucks air from the outside and pushes the air in the chamber out, replacing the air in the chamber.
3 - with fan that takes air from the inner chamber and pushes it out - the air that is taken from the inner chamber is replaced by air from the outside.
So 2 and 3 are basically the same in that air in the shield is continually being replaced by air from the outside. A fan pushes as well as pulls regardless of where it is placed.
So other than the points people like CW2274 have made, I really see no difference. Besides heat being blown into the chamber from the fan if the fan is set to blow directly into it, there may be even a little more heat transfer from the fan if it is placed at the bottom of the shield as heat rises. Unless you have a perfectly efficient and frictionless fan.
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waiting for the meteoshield pro...
here is the ventilated davis 774
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My today's comparison between Davis 7714 with no name thermometer (0,1C range), Davis daytime fan 12V with SHT31, deep deep shadow place with SHT30. Today was a clear day, cloudy weather and moderate wind. Davis radiation shields are all day in the sun, in the same place. The 24 hour fan didn't help much :???:.
High Low
7714 16,6 -1,5
daytime 16,6 -1,2
deep shadow 16,1 -0,5
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Quick update, i am still doing comparison of shields and have some interesting things going on and i am waiting for some longer runs to be sure it is a long time thing and not just a blip. Just to let you know how impressed i am with the new pro i have been running it on my main site for some time now and i have not found anything so far to want to use the fars even in calm to very low wind it is working great so far.
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Another update, pro still working great and we finally got a day when it was sunny, hot temps in the low nineties and the wind went calm around noon time with some upticks of one to two mph but not for long. This went on for a couple of hours until the wind finally picked up after getting to the southeast which is the prevailing wind here. The pro did real well with only a few readings higher than the fars and the max i saw was .5 higher. Looking like the new pro is going to be a winner for passive shields.
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I guess this will be the final report on the pro shield. I just removed my fars and replaced it with the pro because of the great low wind performance of the shield and it matches the fars real well and has some advantages over the fars that i like. One problem with the fars is the stock fan is too weak and gets over powered when the wind gets above 15 to 20 mph, it does not exhaust right and the air intake gets messed up causing high temp readings. I fixed that problem by going to a 12 volt high powered fan which is a must in windy areas. The other problem with the fars is the filter which is too big and messes up the pro air circulation when put in the pro. On average with no wind and full sun the pro averaged .5 degrees warmer but with just a 1 to 2 mph wind it came back down. I had a period of about 3 hours of calm wind and full sun in the morning which is a hard time for shields having the side of the shield to the sun and it only got to .7 higher. Now as the sun got higher and less of the shield was exposed to the sun the temp got even with the fars and at times a few tenths of a degree cooler. The new pro is a real winner but there is one thing i did test and it was a loser. I make most of my own sensors that are very small and do not block the airflow inside the pro. I modify the 31 to get it down to a size of about 1 inch long and 1/2 inch wide plus i replace the filter with one i make from double sided tape with the center cut out to expose the actual sensor and press a small piece of filter over the hole and then stick in down on the board. Now i did try the factory stock 31 and it is hard to stuff inside the pro, the strain relief has to be bent real hard and it would be better to just cut off the material and then the cable would bend easier. But this would void warranty and i would replace the filter like i dig, it is just to big and blocks air flow. I was totally displeased with the performance of the stock Davis sensor, creates a very long lag time at low wind but as the wind picks up it performs pretty well. With a little work the pro is the best choice for me, no batteries and fans to worry about makes it nice.I like everything about the pro.
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I guess this will be the final report on the pro shield. I just removed my fars and replaced it with the pro because of the great low wind performance of the shield and it matches the fars real well and has some advantages over the fars that i like. One problem with the fars is the stock fan is too weak and gets over powered when the wind gets above 15 to 20 mph, it does not exhaust right and the air intake gets messed up causing high temp readings. I fixed that problem by going to a 12 volt high powered fan which is a must in windy areas. The other problem with the fars is the filter which is too big and messes up the pro air circulation when put in the pro. On average with no wind and full sun the pro averaged .5 degrees warmer but with just a 1 to 2 mph wind it came back down. I had a period of about 3 hours of calm wind and full sun in the morning which is a hard time for shields having the side of the shield to the sun and it only got to .7 higher. Now as the sun got higher and less of the shield was exposed to the sun the temp got even with the fars and at times a few tenths of a degree cooler. The new pro is a real winner but there is one thing i did test and it was a loser. I make most of my own sensors that are very small and do not block the airflow inside the pro. I modify the 31 to get it down to a size of about 1 inch long and 1/2 inch wide plus i replace the filter with one i make from double sided tape with the center cut out to expose the actual sensor and press a small piece of filter over the hole and then stick in down on the board. Now i did try the factory stock 31 and it is hard to stuff inside the pro, the strain relief has to be bent real hard and it would be better to just cut off the material and then the cable would bend easier. But this would void warranty and i would replace the filter like i dig, it is just to big and blocks air flow. I was totally displeased with the performance of the stock Davis sensor, creates a very long lag time at low wind but as the wind picks up it performs pretty well. With a little work the pro is the best choice for me, no batteries and fans to worry about makes it nice.I like everything about the pro.
I absolutely agree,
I've tested a lot of solar radiations shields, even professional and more expensive, but not found better value for money than Barani Meteoshield Pro
Mauro
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@jerryg, would you mind posting a pic of your sensor the way you deploy it? I'm confused about the with or without filter...
I have a standard Barani shield coming (the pro is too rich for me) and I deploy my own sensors. Right now I have a 10mm x 10mm PCB with a SHT31 and a 10mm x 14mm PCB with a BME680, both PCBs are stuck together next to each other and there shouldn't be any issue WRT size in the std shield. The SHT31 is without integrated filter and I was planning to start out with putting this stuff naked into the shield with just a bit of conformal coating and see how it goes.
What I'm planing to do is to put a SHT35 and perhaps a BME280 onto a thinner more elongated PCB, but I'm wondering whether it's worth making it fit into one of those $10 "sensor filter caps". The SHT35 can be had with integrated filter right on the chip, which doesn't affect the response time according to Sensirion. I wonder whether that's not the best way to go, the chips are less than $15, so not expensive to swap out if one has the soldering equipment. (I also saw that the SHT75, which people seem to like is replaced by the SHT85 which looks like an SHT35 on a long skinny PCB, that's what I would get if I didn't like to make my own PCBs...)
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The Barani Standard is much more spacious inside vs the PRO. The standard is a good shield if you paint interior flat black preferably with low VOC paint.
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I've had the Pro setup with the factory SHT 31 sensor and I've been pleased with its performance. I cut away the rubber so the cable could be bent and I did remove the big white filter and just put some of the filter paper onto the sensor and secured it with some tape, I think that speeds up the response time. I did not reduce the size of the sensor though, are you saying it would be even better if I reduced the sensor size @jerryg? I'm not too sure it would have a great effect since I've had similar response times to very small sensors in small shields and even bare sensors.
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You can easily trim the sensor down with wire side cutters (dikes) and not cut into the circuit, Jerry really trims them down he may even solder the connections again.
I've been making my own filters with 100 thread silk cloth, just wrap the whole sensor and so far had no issues.
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I'm pretty reluctant to do that really, I don't think it will matter a great deal either if I just remove small parts of the green material
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The Barani Standard is much more spacious inside vs the PRO. The standard is a good shield if you paint interior flat black preferably with low VOC paint.
I just got the Standard shield. It's black on the inside (looking into the shield from below):
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Hi is their other places which I could buy the MeteoHelix® IoT Pro - Sigfox Micro-Weather Station because on the Barani site the delivery fees are ridiculous to the UK.
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Hi is their other places which I could buy the MeteoHelix® IoT Pro - Sigfox Micro-Weather Station because on the Barani site the delivery fees are ridiculous to the UK.
Hi Daniel,
there's a problem on Barani's site about shipment costs to UK, due to Brexit, they are working to fix it
if you email to them you will receive the correct shipment price, my advice is to write directly to
sales@baranidesign.com
Mauro
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very difficult day yesterday for my Davis, this station suffers a lot in the hot summer afternoons, the shading of the ISS is missing and if, like yesterday, there is an appreciable drop in the wind, the situation becomes more complicated, a really bad performance
well the sht30 in the Meteoshield pro, even better the sht35 with only probe in the other Meteoshield pro
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Mauro
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What's the delivery time usually on the MeteoHelix?
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What's the delivery time usually on the MeteoHelix?
I cannot see where are you from, but usually, the Meteohelix Pro is on stock, so you need to wait only the necessary time for shipment
Mauro
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I'm from the UK
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I'm from the UK
well Daniel, my fault ;(
send an email to sales(at)baranidesign.com
Mauro
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What would you guys recommend. Getting the MeteoHelix or get the MeteoShield Pro and put the
WH-32 EP in it?
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What would you guys recommend. Getting the MeteoHelix or get the MeteoShield Pro and put the
WH-32 EP in it?
Hi Daniel, my personal opinion?
you can start with Meteoshield Pro+wh32-EP
you will have very accurate temperature and humidity performances, better than a lot of "professional" systems
Meteohelix has the same performances, the sensor inside the Meteohelix Pro new versions is the same, Sensirion sht35, but much more expensive for to have solar radiation and atmospheric pressure
Obviously I consider Meteohelix Pro a wonderful product, I'm happy with this, and this is the second for me, the older version was the first prototype
Mauro
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Thanks for the feedback. Have you got any comparisons of both the MeteoHelix and WH-32 EP?
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also how good is the battery life on the WH-32 EP?
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also how good is the battery life on the WH-32 EP?
I will try to reply to all your questions
I do not have experience with battery life, I have two wh32-ep versions, but only from few months and wsview battery indicator is at 100%
I presume the same of the standard wh-32
about comparison, you can take a look to these links
https://www.kwos.org/marinadimontemarciano/indexDesktop.php (https://www.kwos.org/marinadimontemarciano/indexDesktop.php)
https://www.ecowitt.net/home/index?id=14231 (https://www.ecowitt.net/home/index?id=14231)
https://www.kwos.org/comparison/ (https://www.kwos.org/comparison/)
Mauro
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Thanks to those who have helped me decide I think I will be ordering the MeteoHelix tomorrow.
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I've just ordered the MeteoHelix 😁😁 I'll let you guys know how I find it.
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I've just ordered the MeteoHelix 😁😁 I'll let you guys know how I find it.
Good choice Daniel ;)
I'm sure you will happy, and I'm at your disposal for any question
let us know the link to your Allmeteo portal when will be ready
Mauro
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Barani MeteoShield Pro Review.
Automatic translate by Google.
http://www.kwos.it/joomla/en/articoli/144-meteoshield-professional-new
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Barani MeteoShield Pro Review.
Automatic translate by Google.
http://www.kwos.it/joomla/en/articoli/144-meteoshield-professional-new
Thanks Raffaello,
great review =D>
Mauro
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I've been reading up a bit on the Meteo Shield Pro as an alternative to the Davis FARS and/or 7714. I'm having a hard time finding out exactly how a regular Davis SHT31 sensor would be mounted. I see it would involve some trimming, but how it fixed inside the shield afterwards? Or would it just be floating?
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I have cut down a lot of sensors to fit the pro, i use a filter i make to get as much air flow inside the shield as possible, the big filter takes up too much room. You can carefully remove the goop that seals the board and by doing that it will let you fold the cable over and down the middle of the board which i use a tie to hold the cable in place and by carefully trimming the board edge opposite the where the cable solders on being careful not to cut the trace on that side you can slide the shield in the clamp. I use a piece of tubing to drop the cable into with the sensor board sitting on the top and just slide it into the clamp. You can avoid trimming by taking the shield off the mount and inserting the tube in from the top so the width of the board is no problem. I lengthen the cable so i don't have to worry about mounting the shield so the factory cable can reach the iss. I also have made up short cables using cat 5 splices to lengthen the cables so i can put the shield anywhere i want up to around 50 feet from the iss, any more than that the sensor might not work. I believe you can use the davis filter ok by inserting the sensor in from the top. The main thing is to remove the strain material so the cable can be folded over to clear the side of the internal shield. Really the cable length is the main thing because it is not very long. Just depends on how much you feel good about doing but it will fit.
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I have cut down a lot of sensors to fit the pro, i use a filter i make to get as much air flow inside the shield as possible, the big filter takes up too much room. You can carefully remove the goop that seals the board and by doing that it will let you fold the cable over and down the middle of the board which i use a tie to hold the cable in place and by carefully trimming the board edge opposite the where the cable solders on being careful not to cut the trace on that side you can slide the shield in the clamp. I use a piece of tubing to drop the cable into with the sensor board sitting on the top and just slide it into the clamp. You can avoid trimming by taking the shield off the mount and inserting the tube in from the top so the width of the board is no problem. I lengthen the cable so i don't have to worry about mounting the shield so the factory cable can reach the iss. I also have made up short cables using cat 5 splices to lengthen the cables so i can put the shield anywhere i want up to around 50 feet from the iss, any more than that the sensor might not work. I believe you can use the davis filter ok by inserting the sensor in from the top. The main thing is to remove the strain material so the cable can be folded over to clear the side of the internal shield. Really the cable length is the main thing because it is not very long. Just depends on how much you feel good about doing but it will fit.
Thanks Jerry. I noticed I missed some great screenshots around page 13 of part of what you describe. Super useful! You or anyone else happen to have an image of the sf2 filter on top of the Davis sht31 board?
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Received my Meteo Shield Pro from Slovakia earlier this week. Installed it yesterday. :-)
Attempted to reproduce mauro63's sollution for the Davis SHT31 sensor. Ended up cutting slightly into the black wire casing twice #-o But it works!
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Received my Meteo Shield Pro from Slovakia earlier this week. Installed it yesterday. :-)
Attempted to reprocude mauro63's sollution for the Davis SHT31 sensor. Ended up cutting slightly into the black wire casing twice #-o But it works!
My compliments for the choice and for the job ;)
only a question about the solar radiation shields exposure, it seems that the Davis and the Meteoshield is exposed to North, it's better to rotate them to South ;)
Mauro
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only a question about the solar radiation shields exposure, it seems that the Davis and the Meteoshield is exposed to North, it's better to rotate them to South ;)
Mauro
I figured I point the 7714 and the Barani North, thinking to prevent windflow from being blocked by the rain collector. Not sure if that even makes sense. What's the thinking about it being better to have the shields point South? Easily fixed of couse. :-)
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only a question about the solar radiation shields exposure, it seems that the Davis and the Meteoshield is exposed to North, it's better to rotate them to South ;)
Mauro
I figured I point the 7714 and the Barani North, thinking to prevent windflow from being blocked by the rain collector. Not sure if that even makes sense. What's the thinking about it being better to have the shields point South? Easily fixed of couse. :-)
the exposure need to be to South due to do not have shadows from the pole, the brackets, and other equipment during the sun hours
the shadows can alterate temperature readings
Mauro
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I read the paper on this station by the Belgian KMI and it looked good. However; there is a much more thorough research done by the KNMI and I also think one that was deployed in Algeria since radiation errors (I guess) run havoc in the desert over there. An abundance of stations was tested there. The Davis 7714 did well btw, but there were others I think that performed may be even better (I did not reread it and last time I did was in 2014 or so).
I would be really keen to know how it works compared to more than just a Davis, a Stevenson Screen and a Young aspirated one (of which we know it gets a wetbulb once it rains with all the aspiration going on). Especially compared to other nonventilated screens it would be interesting to see what the hellical shape does for the radiation errors.
Thx!
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I do not have a RM-YOUNG ventilated but an Apogee ventilated. It doesn't suffer the wet bulb problem because the fan is shut off or blow at low speed when it rains.
You can see the comparison with other solar shields here:
http://www.kwos.org/comparison/
It is an always on comparison.
Inviato dal mio Mi Note 10 utilizzando Tapatalk
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I've seen a well-conducted year-long (I think) comparison of the Barani Pro against an RM Young Aspirated, Campbell Met21 and Metspec standard Stevenson screen, but it's not my data so sorry but I can't really share the detail. I think the Barani was roughly on a par with the Met21, though unsurprisingly the aspirated screen was maybe 0.3C cooler on average in summer daytimes
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Seems that is the comparison done in Humain, Belgium...What I am missing is this: what is the reference screen. So the better you are means the closer you are to the reference screen. Not necessarily the lower temp under high radiation or things like that. At least not to me. I want to be able for instance to compare to KNMI stations. My station is completely out in the field, just grassland. So that qualifies and so I want to be eradicate everything that affects the readings in a way that makes it deviate from the reference. But that is just me and just that perspective. Of course eradicating radiation errors as much as possible is the way to go if you want correct data.
But it is also fun to do it yourself and I can do that. I have a couple of screens and I can esily mount another one to intercompare. We'll see
thx John and Rafaello for your replies!
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Seems that is the comparison done in Humain, Belgium...
The trial I've seen was done in the UK.
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Oh...that is interesting. I will see if I can find it. Thx!
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Oh...that is interesting. I will see if I can find it. Thx!
AFAIK it's not published anywhere (though I could be wrong) - it was a private communication. .
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May be I'll figure it out myself. But 250 euro for just a screen (if I am correct) seems an awful lot just to test it.
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May be I'll figure it out myself. But 250 euro for just a screen (if I am correct) seems an awful lot just to test it.
Maybe you've already seen it, but if not there are also some interesting charts other forum members have shared earlier this year a couple of pages up in this topic.
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https://www.wxforum.net/index.php?topic=39934.0 (https://www.wxforum.net/index.php?topic=39934.0)
if you want to see comparisons of the barani pro with other screens, visit this thread ;)
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Have the Meteo Shield Pro for a few days now, alongside the 7714 and standard VP2 shield. Been looking at the graphs for yesterday and today. While I noticed that yesterday the 7714 and Barani kept mostly in sync, with at best 1 or 2 tenths of a degree between them, today seems to be a very different day. It's a bit warmer, slightly lower winds and possibly overall more sun.
This is yesterday through the night into today. While the 7714 somehow dropped lower than the Barani during the night, the situation is completely reversed during the day.
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This is today:
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I'm surprised at how big the difference is. At times, the 7714 is as much as 1,3 degrees C higher, with the default VP2 shield apparently in between. In general, the Barani temps are very much in line with the nearest official station.
Winds are SE, only thing I can imagine is that the 7714 suffers some blockage of air flow due to the rain collector.
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Have the Meteo Shield Pro for a few days now, alongside the 7714 and standard VP2 shield. Been looking at the graphs for yesterday and today. While I noticed that yesterday the 7714 and Barani kept mostly in sync, with at best 1 or 2 tenths of a degree between them, today seems to be a very different day. It's a bit warmer, slightly lower winds and possibly overall more sun.
This is yesterday through the night into today. While the 7714 somehow dropped lower than the Barani during the night, the situation is completely reversed during the day.
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This is today:
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I'm surprised at how big the difference is. At times, the 7714 is as much as 1,3 degrees C higher, with the default VP2 shield apparently in between. In general, the Barani temps are very much in line with the nearest official station.
Winds are SE, only thing I can imagine is that the 7714 suffers some blockage of air flow due to the rain collector.
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looking at the photo, and I can also be wrong, it seems to me that the pro and davis are oriented to the north and the vp2 to the south, in my opinion you should put all three screens facing south to avoid shading, as they are all undergo shadows, but especially the vp2, if I'm wrong, the better, then I wanted to ask you what sensors you have inside? the standard ecowitt sensors? can? or with the probe? i new wh EP .... i am also carrying out some tests using the meteoshield pro and other screens, including the davis, but they are all with wh31 / 32 EP probe sensors i also put the link above, [ You are not allowed to view attachments ] this is on the roof and includes a meteoshield pro a lastem and a rotronic all with ecowitt probe sensor
this is the position on the ground at 2.05 meters, meteoshield pro and davis 7714 both with wh32 / 31 EP probe all screens are oriented to the south to avoid shading ,
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looking at the photo, and I can also be wrong, it seems to me that the pro and davis are oriented to the north and the vp2 to the south, in my opinion you should put all three screens facing south to avoid shading, as they are all undergo shadows, but especially the vp2, if I'm wrong, the better, then I wanted to ask you what sensors you have inside? the standard ecowitt sensors? can? or with the probe? i new wh EP .... i am also carrying out some tests using the meteoshield pro and other screens, including the davis, but they are all with wh31 / 32 EP probe sensors i also put the link above, [ You are not allowed to view attachments ] this is on the roof and includes a meteoshield pro a lastem and a rotronic all with ecowitt probe sensor
this is the position on the ground at 2.05 meters, meteoshield pro and davis 7714 both with wh32 / 31 EP probe all screens are oriented to the south to avoid shading ,
Yes you are right. I will be flipping them both to the South. The argument against the shading makes sense.
All 3 shields have the the standard Davis SHT31 sensor.
Will be checking out the topic you mentioned. Will try out some translation tool to read what you are saying. ^_^ But I see that it looks like you have similar experiences with the Meteoshield Pro.
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Hi first of all to all that have posted here: thanks so much for all the comparisons. So interesting.
I have done similar things a decade ago (even a bit more). I took saucers that were black and painted the outer parts bright shiny white. The saucers themselves were HDPE matt black so little to do there. I built two. In one I mounted a Tinytag Ultra2 datalogger with calibration certificate and in the other a Davis sensor. The problem with these thermohygrosensors, to me, is that you cannot easily calibrate it. With probes you can use melting ice and say a 10 liter coolbox and fill it with water of 20 and 40 C (for example) and then put the probe in it together with the datalogger and measure both to get a very good indication of the deviations of the probes and then proceed in the field. With an SHT31/35 or whatever you use it is more difficult or timeconsuming.
I ended up putting the Davis sensor in the Vaisala copy I made back then (I had space enough to do that). The saucer were 21 cm across. The cilinder inside was about 7 cm in diametreand about 15 cm high. So no problem there. And so I could directly compare after all.
I already have a Vantage Pro2 painted black but never used it. I probably will do so for fun shortly. It is the passive version.
I wonder since Bairani said that painting black made such a difference to the non-Pro version which essentially performed very alike the 7714 according to them, why not paint you screens mattblack too (your Davis screens). Seems there is a pretty good chance that it will have a discernable effect? We can buy these Davis screens for 40-50 euro or so. If you would achieve something very close to the Bairani that would be huge saving of money. As nice and exotic I 'd say the Bairani look, 250 euro is quite a lot of money I think surely to 40 euro plus some paint.
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Hi first of all to all that have posted here: thanks so much for all the comparisons. So interesting.
I have done similar things a decade ago (even a bit more). I took saucers that were black and painted the outer parts bright shiny white. The saucers themselves were HDPE matt black so little to do there. I built two. In one I mounted a Tinytag Ultra2 datalogger with calibration certificate and in the other a Davis sensor. The problem with these thermohygrosensors, to me, is that you cannot easily calibrate it. With probes you can use melting ice and say a 10 liter coolbox and fill it with water of 20 and 40 C (for example) and then put the probe in it together with the datalogger and measure both to get a very good indication of the deviations of the probes and then proceed in the field. With an SHT31/35 or whatever you use it is more difficult or timeconsuming.
I ended up putting the Davis sensor in the Vaisala copy I made back then (I had space enough to do that). The saucer were 21 cm across. The cilinder inside was about 7 cm in diametreand about 15 cm high. So no problem there. And so I could directly compare after all.
I already have a Vantage Pro2 painted black but never used it. I probably will do so for fun shortly. It is the passive version.
I wonder since Bairani said that painting black made such a difference to the non-Pro version which essentially performed very alike the 7714 according to them, why not paint you screens mattblack too (your Davis screens). Seems there is a pretty good chance that it will have a discernable effect? We can buy these Davis screens for 40-50 euro or so. If you would achieve something very close to the Bairani that would be huge saving of money. As nice and exotic I 'd say the Bairani look, 250 euro is quite a lot of money I think surely to 40 euro plus some paint.
hello, the barani is not only the internal color of black, but also its helical shape that channels the wind, we can say that it is almost a ventilated one ,,, I have tested some screens, even now I have 3 screens in test all passive but the results are obvious, lower than the pro some of a lot too, the davis 7714 if used with the standard sensor the box ones is a disaster, it takes more than 1 degree from the met pro, instead using it with the probe sensor wh31 / 32 EP is much better, painting the bottom plates black, it doesn't always work, I'll try soon, then the davis 7714 which costs 40 uero ???? where is it ? I paid 110 euros for it ](*,)
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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
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What kind of paint would you use to paint the inside black?
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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.
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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. ^_^
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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
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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.
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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
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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!
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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
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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.
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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
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Mauro
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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!
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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
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Hot day here in September, insane how big the difference is between the standard Davis, 7714 and Barani Meteo Shield:
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Hot day here in September, insane how big the difference is between the standard Davis, 7714 and Barani Meteo Shield:
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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]
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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!
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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!
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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:
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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.
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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.
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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 ;)
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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.
In certain parts there simply isn't any open grassland though. I live in the suburbs of Brugge, the open fields you use as a reference simply don't exist here, so it isn't representative to the climate of this area. I think that's the most important thing to keep in mind, you want your observations to be representative for the area you live in.
With regards to the MeteoShield Pro, I've had it since March and I am very pleased with it. I haven't done a scientific comparison/study but I have noticed several improvements on the VP2 standard shield. Most notably, the temperature fall during clear, calm nights is much closer to reality than the slow, delayed cooldown observed in the VP2 shield. This is due to, as you might know, the bulky rain gauge above the VP2 blocking long wave radiation from leaving the shield. During rapid cooling, the VP2 shield can lag behind the true air temperature as much as 2°C, which is very poor if you ask me. You'd expect better from an expensive weather station. I'd love to know whether Davis are aware of this flaw but had to do it to keep it compact, or if they just didn't know this is the case.
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There is plenty of grassland around Brugge. It is in fact very similar to my situation in Middelburg.
A city is not uniform. So 10 people measuring in the city with bright skies will measure vastly different temperatures and no Barani screen will help because the Barani is not the problem. There is no problem. If you have a small garden it is different from someone with a big garden. If you live in a part with mostly concrete and tiles versus one with more water and greenfields. Open area or tall(er) buildings.
It is surely a very good idea to buy a Barani also there, because that screen seems to be least prone to selfheating. I have to say it is pricey compared to other screens like the Davis.
The Davis I think is so slow to respond not due to the rainbucket. I have tested this extensively. Well...not with the bucket on. But it is simply the sensorcap. I won't go into details but 2 C as compared to a professional,calibrated datalogger in a Vaisala screen (which is a screen that is faster than average to respond to falling temperatures) is eay to obtain with the filtercap on. Once removed, there is no difference to speak off. So like some others I exchanged the sensorcapmaterial and now the Davis is measuring really close to the datalogger. Both are in the Vaisala screen. I have a Davis screen painted black inside and not. I might compare these in the field for fun, but I simply do not have a lot of time so I won't promise it. But it is very interesting to do so...
As a final reply: why not remove the bucket? It is easy make an extension cable with adapter. Can be found in every hardware store. I did so, but I do not use the Davis screen. I think you use a Barani so you have a very good reason to not use the Davis screen ever again.
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There may be open grassland here and there but it's not really representative for an urban area. Like you said, a city has very differing conditions so it's impossible to get it perfect, but you can give it a shot. My station is located in a garden that is open on the south side, against a large green area (Sport Vlaanderen Brugge). On the north side there's more vegetation and houses. I think it's quite representative for a suburban environment, with a mix of obstructions (trees/buildings) and open green areas. It is correct that you can't really compare such temperature records to rural, open fields but like I said, I want to be representative for the area I live in.
With regards to the Davis, I did do a little comparison with no filter vs filter. No filter seemed to respond faster, but still waaaaaay slower than my other shield. I ended up removing the large, white filter and just placing a piece of the filter material against the sensor and securing it with some tape. Not the most professional option, but does the job. The same SHT-31 sensor (with only a bit of filter paper) responds way faster in the Barani MeteoShield Pro, it is in line with the small shield I'm comparing to. A study I read about came to the conclusion that the slow response time is likely due to blockage of long wave radiation by the rainbucket. The Davis passive shield itself isn't particularly large, so that can not be the reason either. Removing the bucket isn't really an option with the VP2 as it plays an important part in generating more accurate daytime results. The VP2 passive shield performs very poorly by day without the shade from the rainbucket, it overheats badly.
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This is what I have, modified the sensor a bit so it fits in the MeteoShield Pro.
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hi, thanks first of all for all the time you took to extensively answer my remarks and assumptions. So the Davis screen is slow to repsond due to long wave radiation blocking. And without it it is still measuring poorly during the day, because I gues the rain bucket being black generates an upward flow that is lost or something like that. Otherwise I cannot explain why that bucket would be needed? There is nothing in it I think that generates movement? I have the latest version of the rainbucket. I never used the Davis screens I have (well, i did use the 7714 until 2007 when I made mny Vaisala copy which is pretty easy to do.
I use my SHt31 muhc like you do, but you have put it in the Barani and I in the Vaisala together with the said datalogger from Tiny.
I never read anything about that study but find it very interesting and will look it up.
Thanks again, these discussions over here are really insightfull. So much to learn and always to see new stuff on the market with good scientific backing like Barani is doing. With one caveat basically (for me) this station is almost perfect and it is very inexpensive for what it offers...
I am convinced this is not the end, I hope not and newer and better equipment will be available over time. And more for use to study and may be try & test. I think that in a year o two I will have a complete Barani station likely alongside with my VP2. But who knows.
Vriendelijke groet vanaf Middelburg naar het schitterende Brugge!
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The VP2 cools down too slow at night due to the large rain gauge right above the shield blocking outgoing long wave radiation (heat). By day, because the rain gauge is directly above the radiation shield, it shades the shield substantially so it keeps the error lower. Removing the rain gauge would expose the shield to direct sunlight, which would create a much higher error. So pretty much, if you removed the rain gauge you'd get a cooler min temp but a much higher max temp, if you get what I mean.
The study, where they compare the Stevenson screen vs VP2, came to the same conclusion. Over a yearly period, the VP2 recorded a slightly higher avg min temp than the Stevenson screen and a slightly cooler avg max temp, this because of the factors I just explained. The mean temperature overall was nearly identical to the Stevenson screen.
Ook mijn vriendelijke groeten, leuk om eens met een Nederlands sprekende weerfreak te kunnen praten! :grin:
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Well I can't argue with testresults, but.....But: the Vaisala screen is not too different and does not record such errors. It too has a roof of two closed plates. Much like the Davis. I wonder if the radiation errors could be in part at least explained by the Davis being white inside versus black. I must say that the vaisala has a much more open construction so I guess it is more connected with the surrounding air and radiation errors that should come with it are taken care of by the black, absorbing inside. I remember the white Barani (inside) performed less well than the current black version.
it is very easy to paint the Davis black inside in fact, like I said, I have on such here lying around for 5 years when I had the intention to test it but never did. Who knows, next summer....
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Can you show me a picture of that Vaisala screen? I'm not talking about the structure of the VP2 shield itself, I'm talking about the black rain gauge right above it, that is what is blocking long wave radiation.
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That rain gauge is effectively functioning as a blanket, reflecting outward going heat back onto the shield, so it loses its heat slower at night and lags behind the true air temp.
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Can you show me a picture of that Vaisala screen? I'm not talking about the structure of the VP2 shield itself, I'm talking about the black rain gauge right above it, that is what is blocking long wave radiation.
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Thx, I know how it looks. But something on top is not necessarily blocking anything to that degree. But in this case, it obviously (research is available) is.
This is the Vaisala screen. As you can see it has no double louvres. I am not saying it is the best option, but it is what is used by the KNMI hence to me given my stationsiting the preferable solution.
The KNMI modified Vaisala screen is on page 8. Interesting research, sadly no Barani to compare.
https://bibliotheek.knmi.nl/stageverslagen/traineereport_Proksch.pdf
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Can you post a screenshot of the screen instead? The link isn’t safe according to my pc.
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The VP2 cools down too slow at night due to the large rain gauge right above the shield blocking outgoing long wave radiation (heat). By day, because the rain gauge is directly above the radiation shield, it shades the shield substantially so it keeps the error lower. Removing the rain gauge would expose the shield to direct sunlight, which would create a much higher error. So pretty much, if you removed the rain gauge you'd get a cooler min temp but a much higher max temp, if you get what I mean.
The study, where they compare the Stevenson screen vs VP2, came to the same conclusion. Over a yearly period, the VP2 recorded a slightly higher avg min temp than the Stevenson screen and a slightly cooler avg max temp, this because of the factors I just explained. The mean temperature overall was nearly identical to the Stevenson screen.
Ook mijn vriendelijke groeten, leuk om eens met een Nederlands sprekende weerfreak te kunnen praten! :grin:
I want to add even more than what you wrote.
The distance between the upper cone and the solar shield is very small and in no wind conditions, the heat remains between the shield and the aerocone without being able to escape.
The space is often occupied by the wires of the various sensors arriving at the ISS
The color of the aerocone does not affect. I also colored it white to try but the problem remains.
I also tried to see the screen with more than forty degrees and a thermal camera. The problem remains the lack of ventilation.
The solar panel helps to keep the screen in the shade but being only on one side, it works only on certain days of the year and for certain latitudes.
The only way to make a Davis solar shield work well, is to remove it from the Aerocone and add plates.
I have this screen among mine that I compare every day.
http://www.kwos.org/comparison/ (http://www.kwos.org/comparison/)
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Can you post a screenshot of the screen instead? The link isn’t safe according to my pc.
No, because it is in a pdf file. It is the KNMI...it is site entered by 10000s every day. It is very safe. But it is up to you. Just look up Vaisala DTR-513 (I think) and you'll probably find a pic of a crosssection somewhere (well to be honest I did once so it seems to be very dependent on the exact wording of your search).
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The VP2 cools down too slow at night due to the large rain gauge right above the shield blocking outgoing long wave radiation (heat). By day, because the rain gauge is directly above the radiation shield, it shades the shield substantially so it keeps the error lower. Removing the rain gauge would expose the shield to direct sunlight, which would create a much higher error. So pretty much, if you removed the rain gauge you'd get a cooler min temp but a much higher max temp, if you get what I mean.
The study, where they compare the Stevenson screen vs VP2, came to the same conclusion. Over a yearly period, the VP2 recorded a slightly higher avg min temp than the Stevenson screen and a slightly cooler avg max temp, this because of the factors I just explained. The mean temperature overall was nearly identical to the Stevenson screen.
Ook mijn vriendelijke groeten, leuk om eens met een Nederlands sprekende weerfreak te kunnen praten! :grin:
I want to add even more than what you wrote.
The distance between the upper cone and the solar shield is very small and in no wind conditions, the heat remains between the shield and the aerocone without being able to escape.
The space is often occupied by the wires of the various sensors arriving at the ISS
The color of the aerocone does not affect. I also colored it white to try but the problem remains.
I also tried to see the screen with more than forty degrees and a thermal camera. The problem remains the lack of ventilation.
The solar panel helps to keep the screen in the shade but being only on one side, it works only on certain days of the year and for certain latitudes.
The only way to make a Davis solar shield work well, is to remove it from the Aerocone and add plates.
I have this screen among mine that I compare every day.
http://www.kwos.org/comparison/ (http://www.kwos.org/comparison/)
Interesting, thanks for the comment. Think we can all agree there's a flaw in the VP2 design. I've solved it by geting a MeteoShield Pro, but there's probably cheaper options aswell.
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Been running the Barani Pro shield for a couple of weeks now, alongside the Campbell Scientific Met21 shield, Davis Vantage Vue and Davis VP2+ w/24 hr fan. All equipped with calibrated Davis sensors.
Have to say it’s been a disappointment so far. Running 0,5-0,8c higher than the fan aspirated shield on calm, sunny days. So far it is no better than the MET21 (which is also black inside). In fact it’s giving me quite the same readings as the Vantage Vue. As of now the Barani shield is unfortunately nowhere close to being an alternative to the fan aspirated shield for me.
I live on 59 degrees north and the sun angle is starting to get low these days. I guess that can influence on the accuracy of the shields. Anyway, I will compare all four of them during all of next year so the jury is still out 8-)
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Do you have any graphs where you compare shields?
I see the photo, how are the solar screens oriented? The Vue looks opposite to the others, I see shadow on it while the others are hit by the sun.
I compare many solar shields every day. Two of them are Barani, so I'm curious to understand why it goes like this with you.
http://www.kwos.org/comparison
Thank you
Raf
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I see the photo, how are the solar screens oriented? The Vue looks opposite to the others, I see shadow on it while the others are hit by the sun.
Specifically on the Vue: If you think about the design (ie with the solar panel facing south) then its small shield will be at least partially in the shade of its ISS body relative to the midday sun. Of course this is less true 2-3 hours either side of midday, but it still helps to give the inexpensive Vue an adequate temperature performance (though I wouldn't expect it to be fully on a par with the VP2, let alone other substantially more expensive shields such as the Barani one.
But, just to reiterate, Jarle's results do mirror what I've seen reported in another recent trial for the Barani Pro, ie approaching the Campbell Met21 in performance.
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But, just to reiterate, Jarle's results do mirror what I've seen reported in another recent trial for the Barani Pro, ie approaching the Campbell Met21 in performance.
So, without thinking about the Vue, I will be able to agree with you about the MET21 when, next summer (now it is no longer time to test solar shields) I will finish testing the MetSpec shields that are nothing but the campbell
You can see two of them on my comparison page, called RAD02 and RAD14.
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As of now the Barani shield is unfortunately nowhere close to being an alternative to the fan aspirated shield for me.
I forgot to mention that no passive can be a substitute for a forced ventilation one. Especially if the area is often windless and strong sunshine.
However, the forced ventilation shield must have the fan controlled by software. It cannot be left on all the time.
Raf
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Do you have any graphs where you compare shields?
I see the photo, how are the solar screens oriented? The Vue looks opposite to the others, I see shadow on it while the others are hit by the sun.
I compare many solar shields every day. Two of them are Barani, so I'm curious to understand why it goes like this with you.
http://www.kwos.org/comparison
Thank you
Raf
Raf,
The MET21, Barani and VP2+ are all facing south. I have lined them up very carefully so they get equally exposed for sun.
Not the best of graphs, but as you can see of the comparison charts from the VP2+ (orange color) and the Barani shield on this clear and mostly calm afternoon, the difference appears after 4 pm. At the same time the sun angle is getting very low at this time of year. I believe the low sun angle to some extent gives the same effect on radiation shields as radiation from snow.
Due to the low sun angle during winter months, the Norwegian Met Office have designed their very own radiation shield that is being used with all official weather stations in Norway. For instance I also own a MA11 shield used by KNMI in The Netherlands, and that is completely useless during winter where I live as the low sun shines directly on the sensor inside the shield (the angle on plates is too poor).
The Vue is btw not a part of the original setup. It was originally planned for another location. As you have noticed the temperature sensor is partly in shadow during the day so it will not get a fair comparison with the other three.
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Raf,
The MET21, Barani and VP2+ are all facing south. I have lined them up very carefully so they get equally exposed for sun.
Not the best of graphs, but as you can see of the comparison charts from the VP2+ (orange color) and the Barani shield on this clear and mostly calm afternoon, the difference appears after 4 pm. At the same time the sun angle is getting very low at this time of year. I believe the low sun angle to some extent gives the same effect on radiation shields as radiation from snow.
Really perfect Jarle,
the behavior of the two shields is perfectly in line with expectations.
My tests also report similar results compared to an artificially ventilated solar shield.
And my Apogee does not have the fan always on at maximum speed, otherwise you would notice even more difference.
http://www.kwos.it/joomla/it/articoli/144-meteoshield-professional-new
But let's remember that we are comparing two different types of shields.
Ventilated screens also have their strengths and weaknesses.
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Raf,
The MET21, Barani and VP2+ are all facing south. I have lined them up very carefully so they get equally exposed for sun.
Not the best of graphs, but as you can see of the comparison charts from the VP2+ (orange color) and the Barani shield on this clear and mostly calm afternoon, the difference appears after 4 pm. At the same time the sun angle is getting very low at this time of year. I believe the low sun angle to some extent gives the same effect on radiation shields as radiation from snow.
Really perfect Jarle,
the behavior of the two shields is perfectly in line with expectations.
My tests also report similar results compared to an artificially ventilated solar shield.
And my Apogee does not have the fan always on at maximum speed, otherwise you would notice even more difference.
http://www.kwos.it/joomla/it/articoli/144-meteoshield-professional-new
But let's remember that we are comparing two different types of shields.
Ventilated screens also have their strengths and weaknesses.
I agree, and I would like to add that could be useful to have a comparison of Met21 vs Meteoshield Pro, not necessary with graphs, could be enough csv files, complete with wind and solar radiation data
Mauro
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Really perfect Jarle,
the behavior of the two shields is perfectly in line with expectations.
My tests also report similar results compared to an artificially ventilated solar shield.
And my Apogee does not have the fan always on at maximum speed, otherwise you would notice even more difference.
http://www.kwos.it/joomla/it/articoli/144-meteoshield-professional-new
But let's remember that we are comparing two different types of shields.
Ventilated screens also have their strengths and weaknesses.
Raf,
I went through your webpage and you are playing in another league than me when it comes to radiation shield comparison. Very nice and very helpful!
I agree with your conclusion regarding passive vs. fan aspirated shield. Interesting enough, though, my observation is that those late afternoon errors doesn't seem to apply to the same degree on the MI-74 radiation shield designed and used by the Norwegian Met Office (all passive). Picture below.
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The most interesting part for me personally will be whether the Barani shield will better the readings from those of the MET21. Next summer I'll hopefully find out.
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However, the forced ventilation shield must have the fan controlled by software. It cannot be left on all the time.
I must have missed that note. My 24hr aspirated VP2 with a 60CFM case fan has been running full power 24/7/365 for over five years. Also, practically all of our "official" measurements in the US come from airport aspirated ASOS's. Their fans run 24/7/365 as well.
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What is the price of the MET21 also will it fit the WH32-EP? I've got the MeteoHelix just looking to compare other radiation shields😁
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However, the forced ventilation shield must have the fan controlled by software. It cannot be left on all the time.
I must have missed that note. My 24hr aspirated VP2 with a 60CFM case fan has been running full power 24/7/365 for over five years. Also, practically all of our "official" measurements in the US come from airport aspirated ASOS's. Their fans run 24/7/365 as well.
Yes I know this. The reason why I wrote it, is not because they break easily, but because there are studies that confirm some situations of overcooling the sensor inside due to the use of the fan in conditions of rain, freezing rain, etc.
I preferred to use the pwm function that all professional screens have to adjust the fan according to the weather conditions.
Read my review on the Apogee: http://www.kwos.it/joomla/it/articoli/145-schermo-solare-aspirato-apogee-ts-100
Of course, even in this case, mistakes can be made ...
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I agree with your conclusion regarding passive vs. fan aspirated shield. Interesting enough, though, my observation is that those late afternoon errors doesn't seem to apply to the same degree on the MI-74 radiation shield designed and used by the Norwegian Met Office (all passive).
Yes, indeed it is interesting. I have never tested an MI-74.
It is also likely to perform well or perform better only in certain situations.
Do you have it in the same location? Or are you comparing it to another similar weather station?
I will find out more about the MI-74.
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However, the forced ventilation shield must have the fan controlled by software. It cannot be left on all the time.
I must have missed that note. My 24hr aspirated VP2 with a 60CFM case fan has been running full power 24/7/365 for over five years. Also, practically all of our "official" measurements in the US come from airport aspirated ASOS's. Their fans run 24/7/365 as well.
there are studies that confirm some situations of overcooling the sensor inside due to the use of the fan in conditions of rain, freezing rain, etc.
How does a fan "over-cool" ambient air temperature? Wind chill factor is irrelevant to a sensor.
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How does a fan "over-cool" ambient air temperature? Wind chill factor is irrelevant to a sensor.
it is not a question of wind chill but of contact of suspended particles colder than the normal temperature of the surrounding air, which are carried by the fan itself on the surface of the thermometer.
http://www.kwos.it/joomla/it/articoli/151-overheating-e-overcooling-degli-schermi-solari
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How does a fan "over-cool" ambient air temperature? Wind chill factor is irrelevant to a sensor.
it is not a question of wind chill but of contact of suspended particles colder than the normal temperature of the surrounding air, which are
Nope, don't see it. What happens to a passive shield during moderate or greater winds in high RH's? Let's say a simple tropical storm, if even that. I guess that would be a skewed temp as well? Unless you group all wind flow, not just aspirated but passive into your reasoning, nope, don't see it.
The only time I will agree to a fan being somewhat influential, in the negative, is if the sensor is directly measuring only the dew point.
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Nope, don't see it. What happens to a passive shield during moderate or greater winds in high RH's? Let's say a simple tropical storm, if even that. I guess that would be a skewed temp as well? Unless you group all wind flow, not just aspirated but passive into your reasoning, nope, don't see it.
The only time I will agree to a fan being somewhat influential, in the negative, is if the sensor is directly measuring only the dew point.
Well, of course, everyone can have their own ideas.
It is possible that with a tropical storm could also happen for passive screens, but in that case, it is an atmospheric condition and not a "human mechanical" element that causes.
In fact, even single-chamber passive solar shields (those of old conception) can suffer from a similar phenomenon.
For double chamber screens, it is necessary to have even stronger winds during "cold" rainy phenomena.
I speak on the basis of direct experiences and on experiments carried out ad hoc to study this phenomenon.
Studies carried out by research centers.
However, this is not the thread to discuss these things. I guess.
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Nope, don't see it. What happens to a passive shield during moderate or greater winds in high RH's? Let's say a simple tropical storm, if even that. I guess that would be a skewed temp as well? Unless you group all wind flow, not just aspirated but passive into your reasoning, nope, don't see it.
The only time I will agree to a fan being somewhat influential, in the negative, is if the sensor is directly measuring only the dew point.
It is possible that with a tropical storm could also happen for passive screens, but in that case, it is an atmospheric condition and not a "human mechanical" element that causes.
However, this is not the thread to discuss these things. I guess.
Well, if that's the case, then I much rather have a constant, a fan, that is just that, a constant, consistent flow, not one dictated by the "weather". Kinda the whole idea of a well aspirated shield, you never care about the wind..ever.
As far as "this isn't the thread", sure seems relevant to me.
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It is possible that with a tropical storm could also happen for passive screens, but in that case, it is an atmospheric condition and not a "human mechanical" element that causes.
However, this is not the thread to discuss these things. I guess.
Well, if that's the case, then I much rather have a constant, a fan, that is just that, a constant, consistent flow, not one dictated by the "weather". Kinda the whole idea of a well aspirated shield, you never care about the wind..ever.
As far as "this isn't the thread", sure seems relevant to me.
In a thermodynamic system such as that of the very first PBL layer, it is not enough to have the fan always on to say that I have a constant and I am no longer interested in the wind.
I wish it were that simple. The wind carries particles in the air which still affect the temperature.
In my opinion and I repeat, it is just my opinion, we should use the technology to the fullest and since many fans now have PWM that allows you to adjust the speed. I speak for professional sunscreens. The amateur ones do not have this possibility and therefore we will always keep them on, even if we know their characteristics.
We have to "help" the thermometer to better follow the real air temperature.
As a reference we can try to have a thermometer in free air and use the energy balance formula to correct the radiative error. Or, as is done with radiosondes, use two different colored thermometers and calculate the radiative error.
Obviously, never really knowing what the true air temperature is in a complex thermodynamic system, we can never think of having a certain reference even if calculated with physical formulas.
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I speak on the basis of direct experiences and on experiments carried out ad hoc to study this phenomenon.
Studies carried out by research centers.
Never read of this phenomenon and not going to argue the possibility of this happening under certain rare circumstances. Can't see where this would happen even a couple times a year, if that, where I live. Will stick with the fan running 24/7 at my place.
Doug
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Never read of this phenomenon and not going to argue the possibility of this happening under certain rare circumstances. Can't see where this would happen even a couple times a year, if that, where I live. Will stick with the fan running 24/7 at my place.
Doug
I agree with your decision. Only those who are local or know their area well from a meteorological point of view can decide what to do.
Although it is advisable to have both a ventilated and a passive solar screen to be able to notice this type of phenomena.
Raf
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There are two reasons I don't like fans:
1) What if it stalls? Some screens like the Davis 24H will get you very high temperatures. I have one of those Davis screens....with a broken fan.
2) Drawing air over the sensor often means drawing moist over the sensor. More than otherwise would be the case. This means you are measuring the wetbulb and no longer the dry (or drier) bulb.
For us it will be difficult to tell what causes what exactly. In order to assess you are not measuring a wetbulb you need to have a drybulb. That will note higher temperature but how can you tell for sure when the dry bulb of course cannot be housed in a screen with a fan since you would measure the same. But if you measure in a less ventilated screen, may be you are measuring a higher temp due to radiation error. Let alone getting a calibrated sensor with certificate (two at least)...
Suffice to say i don't like artificially ventilated screens in MY case since my weatherstation is 3 miles away in the open and flat countryside northeast of my city. I can't go and check the screen very often to check if the fan is still working.
So I prefer naturally ventilated screens. As far as I can tell it seems that throrough tests show that the Barani does perform better than other screens. What those thorough tests do lack, as far as I know, is being extensive. I have only come across comparisons with 2-3 screens. I would love to see how it performs among a group like the famous test done in Algeria.
Still: the Barani seems to have a lot going for it.
@ Jarle: a few notions.
1) KNMI uses the same screens as the SMHI does. I have one. There are no problems with low angles with or without snow. In a direct comparison with lots of snow and sun for a few weeks in januari (and end of march) 2013 I had the Vaisala and the Davis simultaneously. The Davis went berzerk going to +3,6 C whereas the Vaisala remained at 0 C. Indeed it was a very sunny, bright day aftr -10 C in the morning and -11 C the next morning.
I made this movie (below), which is nice and all but just to give you an indication of the sunny and bright weather and the amount of snow since most pics were in the fields right next to my weatherstation. The frozen fog in the movie with the -13,3 C are the wires that protect my station from horses...So the snowcover was always between 10-20 cm from 13-27 january. The max over that period is 0,8 C on one day, another day had 0,4 C and all others remained well below freezing which is important because dry snow is more reflective than wet snow. Also because we had some cms of snow on every other day the cover was fresh and white for that reason too. A long winded way to tell you that this was a situation with low angles and lots of reflections. But the Vaisala screen did fine as we would expect from a screen used in Sweden too.
https://vimeo.com/66656873 (https://vimeo.com/66656873)
2) Your notion that the Barani (and the Met21?) are getting youhigher temperatures at low solar angles these days...You live at 59 N so that has to be pretty close to the Northsea. Where I live at 52 degrees. It is wet here with 200+ mm or more in the past mpnth or so. So a bright sunny day with you is probably very similar to one such day here. And such days become moist and foggy once the sun goes down. So it might be that your Davis is indeed measuring the wetbulb and no longer a drybulb. So it will get you lower temperatures but the screen in error could be the artificially aspirated Davis with the fan drawing moist air over the sensor.
Nothing definitive, just some notions and an interesting discussion I think!
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I saw it with great pleasure.
I agree with everything you said about artificially ventilated solar shields. It would also be necessary to have an alarm for a broken fan, to be able to replace it immediately.
Even the Apogee, with the fan stopped, has a big mistake if the wind is not sustained.
You can find a graph of this test in my review.
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There are two reasons I don't like fans:
1) What if it stalls? Some screens like the Davis 24H will get you very high temperatures. I have one of those Davis screens....with a broken fan.
2) Drawing air over the sensor often means drawing moist over the sensor. More than otherwise would be the case. This means you are measuring the wetbulb and no longer the dry (or drier) bulb.
1) Hence why those of us that are able and willing use a computer case fan. Mine is rated at 70,000 hours of use. I also have a red LED on the 120vac to 12vdc transformer that sits on top of the shield that tells me it's getting power. I can also simply go outside and hear it sucking air from 40' away.
2) How does a fan cause the air to be more "wet"?? Do you not think that a a passive shield sensor doesn't get "wet" as well? Just because the fan is drawing ambient air across the sensor doesn't make the air more concentrated with water vapor. Nothing a fan does makes the wet vs dry bulb one bit different...certainly not of consequence in PWS land. Fourteen years of aspirated PWS ownership and relentless comparisons make my case as well.
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Hi,
Thanks for your thoughts.
1) Drawing more air over the sensor, according to research, causes the sensor to become wetter. Just what research says.
2) There is more to it: the stronger the fan the more it influences the environment outside your screen, again according to research. So on still calm days and nights (I think especially nights) it is like you have some local wind blowing around your station. So a cold night will get less cold and a warm day less warm due to mixing of air, like wind.
3) I swear I tried, but I could not hear the Davis fan in my station 3 miles away. I thought it was my ears but I got in the car and pfoooh: it was broken...Nothing wrong with my ears it seems
4) I know you Americans have 3 holidays ever decade, but we Europeans have 30-40 such days per year (payed by our boss). So we go to places where the fan is not 40 feet away....In other words: how are you going to take care of your fan, in the summer (when people tend to enjoy a nice trip to sunny beaches etc) when it is most needed.
Now this seems far fetched, but at least I am pretty anal about trying to measure as carefree and accurate as possible. A fan that breaks down a fan that breaks down a calm atmosphere around the screen and/or a fan that creates a wetbulb is not helping me. But to each their own!
I can tell you that on cold bright nigts the Davis VP2 in my neighborhood measures higher temperatures than I do. Now he is 12 km away....But in the same very open flat countryside. And 2 km to his east is a KNMI Vaisala station and it also gets lower temperatures during the night than he does. In fact that very user is looking into the Barani, I think for that reason.
It might be better to have a screen with solar aspiration. No sun? No aspiration. But the construction of the Davis would block wind big time. So for a VP2 24h aspirated screen it is probably still not an option.
There is no ideal which is nice for curious people like me, who want to see if there is some ideal that is yet to be discovered. The Barani seems like an excellent effort and it is very interesting if indeed radiation errors are the cause of Jarle's disappointing results.
Edit: here is the research. Sadly this research was done in the most snowpoor period ever in The Netherlands still some interesting results that to some extend coroborate Jarles findings I just read! After 1995 until 2013 the snowcover was still below the average from 1901-1988, but a lot better than 1991-1995. But still some remarkable differences are noted during those days.
https://projects.knmi.nl/klimatologie/onderzoeksgegevens/homogeen_260/meulenbrandsma2007b.pdf (https://projects.knmi.nl/klimatologie/onderzoeksgegevens/homogeen_260/meulenbrandsma2007b.pdf)
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1) Drawing more air over the sensor, according to research, causes the sensor to become wetter. Just what research says.
2) There is more to it: the stronger the fan the more it influences the environment outside your screen, again according to research.
3) I swear I tried, but I could not here the Davis fan in my station 3 miles away. I thought it was my ears but I got in the car and pfoooh: it was broken...Nothing wrong with ears it seems
4) So we go to places where the fan is not 40 feet away....In other words: how are you going to take care of your fan, in the summer (when people tend to enjoy a nice trip to sunny beaches etc) when it is most needed.
1/2) Well, I can "research" as well...and have for a looong time.
3/4) :roll: Sarcasm will get you nowhere.
Tell ya what...you stay passive and I won't. ;)
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Man don't take it so serious. I was just joking! I really appreciated your input and understand your position very well, but I don't like to use the smileys etcetc. I should not need them when I am (I thought) obviously joking. Sorry that it came across in a wrong way!
It was may way of saying: for me it doesn't work and I understand that for you it does, since i clearly wrote "in MY case". Because I do go on holidays and what happens then? And I already noted I live 3 miles from my station, so what than? Not a problem for you, but a serious problem for me.
I love to research and read research and learn, which is why i also visit these fora. Again: sorry I wasn't clear I for not being serious and teasing you a bit.
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Again: sorry I wasn't clear I for not being serious and teasing you a bit.
No worries. I DO take my PWS seriously, probably more so than most. I don't think of it as a mere hobby. I was blessed/cursed with being a perfectionist, and my PWS is just one my foibles.
Besides, the wink was just that... I see your way, I see mine. ;)
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Fine. I am not a perfectionist per se, only when it comes to astronomy and meteorology and apparantly renovating a house...I also want to test and try myself and see what I can do. Also when it comes to these screens I always think: we should do better? I think and think and think that I could do better! But that is not very realistic but it IS worth a try. With 3D printing making your imaginary designs a reality has become a whole lot easier. etc.
I provided a link in my previous messages. May be it is interesting for you too? Have a good day.
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So I've noticed that the sensor in the Pro Shield tends to show slightly lower humidity percentages. My only other comparisons are two other SHT31s, not in Pro Shields, which track each other well.
I haven't yet checked the same sensor in a different shield. It may very well just come down to the sensor itself.
Anyone have specific experiences?
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So I've noticed that the sensor in the Pro Shield tends to show slightly lower humidity percentages.
Unless your temps are always the same, using the humidity to compare can be misleading. For a true comparison, use your dew point temp., it is a constant.
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If I can suggest an experiment, connect the T / H sensor from Barani to another transmitter. In my opinion, the voltage may influence the humidity measurements. I once tested it on a Davis Vue that was draining the batteries fast. I connected the ISS to DC power from the power supply after the conversion. Humidity very often reached 100%. It was interesting.
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If I can suggest an experiment, connect the T / H sensor from Barani to another transmitter. In my opinion, the voltage may influence the humidity measurements. I once tested it on a Davis Vue that was draining the batteries fast. I connected the ISS to DC power from the power supply after the conversion. Humidity very often reached 100%. It was interesting.
I'll try that!
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1) Hence why those of us that are able and willing use a computer case fan. Mine is rated at 70,000 hours of use. I also have a red LED on the 120vac to 12vdc transformer that sits on top of the shield that tells me it's getting power.
Have you considered (dry) heat coming from the LED, its driver, its transformer, or the fan itself? They're definitely not all cool, not even the Noctuas, and two issues that I have seen with my own eyes;
The lady of the house wanted christmas lights in the garden, when we still only had a small garden, they were a few meters away from my then Weather-Pro sensor-box. Suddenly, in the long-term trend, I noticed higher temps only when the wind blew in the wrong direction, coming from where the transformer was. And a similar deviation I've seen on a dracal sensor that I used in a server-room few years ago where a Noctua ULN fan was below the sensor. I expected it to read cooler temps because of more airflow in general in the area, but instead noticed about 0.5 C higher overall, and not because warm air was driven and mixing in the room, but because the sensor was mounted about 20 cm above one side of the fan itself. Just an FYI..
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1) Hence why those of us that are able and willing use a computer case fan. Mine is rated at 70,000 hours of use. I also have a red LED on the 120vac to 12vdc transformer that sits on top of the shield that tells me it's getting power.
Have you considered (dry) heat coming from the LED, its driver, its transformer, or the fan itself? They're definitely not all cool
That's exactly why the ISS design is such that all those components are above the sensor. Nothing but ambient air is drawn across the sensor inside the sensor chamber as it's pulled in from below.
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Expecting my second shield in the mail this week. Oh joy. ^_^ Going to set it up with an SHT35 linked to an Arduino board and solar panel.
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As of now the Barani shield is unfortunately nowhere close to being an alternative to the fan aspirated shield for me.
I forgot to mention that no passive can be a substitute for a forced ventilation one. Especially if the area is often windless and strong sunshine.
Just to add here, we live on a wide open polder area, almost marine (Dutch) climate, the amount of hours without any airflow is negligible, so I've never opted for fan aspirated shields, especially since humidity readings would be skewed from it. I want to chime in to say that the MeteoHelix IoT Pro shield far outperforms all other shields here in the area, even the Stevenson case we have in the same field. The Pressure readings of the MeteoHelix Pro are very accurate, I'm not sure what sensors Barani uses, but they're definitely not overpricing their hardware! Noteworthy is that, just like with brands like Mikrotik (from Latvia), BaraniDesign can build and produce hardware with much lower cost due to the Slovakian tax-system and trade agreements internationally. Much lower than most other EU nations. Income tax and land tenure cost alone are extremely high in, for example, The Netherlands, where I live.
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I am wondering what to make of this. I've added a second Barani Pro shield a while back and have been waiting for some sunshine to see how the SHT35 sensor I've added to it fares compared to the Davis SHT31's in my other Barani shield and the default Davis shield.
See below. I note that when the sun comes out, the new SHT35 jumps a few tenths compared to the two SHT31's. As I'm writing this, solar radiation is stable and the SHT35 remains 2-3 tenths higher. Normally, the three sensors are within 1-tenth.
Question: could this be related to the placement of the sensor inside the shield? The probe is fairly short, and I have not yet extended it like I've done with the SHT31. So it's pretty much located all the way at the bottom of the shield.
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I've added a second Barani Pro shield a while back and have been waiting for some sunshine to see how the SHT35 sensor I've added to it fares compared to the Davis SHT31's in my other Barani shield and the default Davis shield.
See below. I note that when the sun comes out, the new SHT35 jumps a few tenths compared to the two SHT31's. As I'm writing this, solar radiation is stable and the SHT35 remains 2-3 tenths higher. Normally, the three sensors are within 1-tenth.
Question: could this be related to the placement of the sensor inside the shield? The probe is fairly short, and I have not yet extended it like I've done with the SHT31. So it's pretty much located all the way at the bottom of the shield.
So you've replaced the barani sensor with an SHT35 ? And it is lower in the shield than where barani put theirs? I would assume a difference in where it is located inside the shield, no doubt. Less airflow in the bottom end could be logical, I would assume it's best exactly in the middle.
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I've added a second Barani Pro shield a while back and have been waiting for some sunshine to see how the SHT35 sensor I've added to it fares compared to the Davis SHT31's in my other Barani shield and the default Davis shield.
See below. I note that when the sun comes out, the new SHT35 jumps a few tenths compared to the two SHT31's. As I'm writing this, solar radiation is stable and the SHT35 remains 2-3 tenths higher. Normally, the three sensors are within 1-tenth.
Question: could this be related to the placement of the sensor inside the shield? The probe is fairly short, and I have not yet extended it like I've done with the SHT31. So it's pretty much located all the way at the bottom of the shield.
So you've replaced the barani sensor with an SHT35 ? And it is lower in the shield than where barani put theirs? I would assume a difference in where it is located inside the shield, no doubt. Less airflow in the bottom end could be logical, I would assume it's best exactly in the middle.
No, my first Barani shield has a Davis SHT31 with some slight modifications to fit inside the shield, as copied from examples earlier in this topic. It's located more in the middle as you say, as I've used some pvc tubing to get it into place. This sensor has given me great results during the summer compared to the standard shield and the 7714 shield.
My assumption is that adding the SHT35 probe (https://nl.aliexpress.com/item/4001220756351.html?spm=a2g0s.9042311.0.0.70234c4dEBTHiQ) will see the same results in a second Barani shield I added. All sensors, incuding the SHT35 track each other very well most of the time. The only thing I can think of is that the placement is not great. So I'll be moving it to see if that has the desired effect.
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hi, after many tests with my meteshield pro and sht35 EP sensor, the optimal position for the sht35 probe is this [ You are not allowed to view attachments ]
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hi, after many tests with my meteshield pro and sht35 EP sensor, the optimal position for the sht35 probe is this
Thanks for that! What kind of material did you use to extend the length of the probe body?
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hi, after many tests with my meteshield pro and sht35 EP sensor, the optimal position for the sht35 probe is this
Thanks for that! What kind of material did you use to extend the length of the probe body?
i used a piece of a carbon fishing rod, but you can use a pvc pipe the diameter of the sensor base
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My assumption is that adding the SHT35 probe (https://nl.aliexpress.com/item/4001220756351.html?spm=a2g0s.9042311.0.0.70234c4dEBTHiQ) will see the same results in a second Barani shield I added.
Did you add this sensor directly to your Davis VP2 base? Interesting ali link you've posted there.
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My assumption is that adding the SHT35 probe (https://nl.aliexpress.com/item/4001220756351.html?spm=a2g0s.9042311.0.0.70234c4dEBTHiQ) will see the same results in a second Barani shield I added.
Did you add this sensor directly to your Davis VP2 base? Interesting ali link you've posted there.
No the sensor is connected to custom setup with a Wemos microcontroller. (Inside the box next to the left of the Davis Rain collector)
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This should work.:-)
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Hello to everyone
During my 2 yeas of scientific researtch in passive radiation shields, I want to put into conversation some desigh parameters which I thing they are very interesting:
1. The time constant of the temperature devices which is very important and differs when several coatings of the sensor are used
2. The performance of the radiation shield/temperature sensor under low wind speed (less than 1 m/sec)
3. The position of the sensor inside the shield
4. The material of the shield (ABS plastic, PVC, HDPE...), affects the performance especially during the night when long wave radiation is important
Generally speaking, as a results from my experience, the test periode of the radiation shields performance must be more than 1 month and at least with 5 min time intervals. This month couldnot be the only June or December, preferable the period between May and September.
Mean temperature error, mean absolute error and root mean square error during this period must be calculated in order to check the performance. In addition, the difference between max, min and average temperature could be one more option. All these parameters need a more accurate reference temperature device, which must be of course arificially ventilated.
And something more...dont forged the need of calibration of the devices owing to the drift of the sensor!
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My assumption is that adding the SHT35 probe (https://nl.aliexpress.com/item/4001220756351.html?spm=a2g0s.9042311.0.0.70234c4dEBTHiQ) will see the same results in a second Barani shield I added.
Did you add this sensor directly to your Davis VP2 base? Interesting ali link you've posted there.
It would be nearly impossible to add the SHT35 to the VP2 because the SHT35 only comes with I2C bus protocol version and the VP2 does not support this. The VP2 uses the SHT31 because it is available in LSS (Lagacy Sensiron Sensibus) version. The SHT31 also comes in I2C version. Therefore the VP2 is limited to no better than the SHT31.
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Well it definitely looks like adjusting the placement of the sensor has had desired effect. Of course I'll have to wait until summer to see how it really fares, but the jumps in temp under solar radiation spikes are gone for the SHT35. :-)
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This should work.:-)
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Is that 1/2 " pvc pipe ...
Just installed my Meteoshield Pro with Ecowitt 32wh-ep sensor and i have to say comparing this to a converted and painted inside flat black vp2 24h newer year old sht 31 sensor is that right of the bat 10% Humidity difference at peak but overall all day is around 7%..
As far as Temp very quick response with Pro shield compared to Davis but as 40 Latitude there is very littles sun now. High temp .5F lower on pro but was the same for low for 1 day comparison ...
Just checked Barani web site and sensor placement is 7.5cm +-2.5cm so around 3+ inches from base
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This should work.:-)
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comparing this to a converted and painted inside flat black vp2 24h
This is not meant as a criticism, my VP2 has modifications as well, but the 24hr VP2 shield is patented. The sensor chamber has the large, black disc at the bottom for this purpose. Do you feel your mod is necessary/beneficial over stock?
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This should work.:-)
[ You are not allowed to view attachments ]
comparing this to a converted and painted inside flat black vp2 24h
This is not meant as a criticism, my VP2 has modifications as well, but the 24hr VP2 shield is patented. The sensor chamber has the large, black disc at the bottom for this purpose. Do you feel your mod is necessary/beneficial over stock?
No worries , My vp2 is total Frankenstein started as standard vp2 then added daytime fars and ended up with 24h conversion ...
and its for sale , best offer
(https://live.staticflickr.com/65535/50784593982_e42aa2da75_n.jpg) (https://flic.kr/p/2knEjtY)20201224_112231 (https://flic.kr/p/2knEjtY) by Marcin Madry (https://www.flickr.com/photos/lysawy/), on Flickr
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So we have had a lot of snow (for our standards, about 15-30 cm of snow fell in most parts of the country) and since yesterday it has been very sunny and bright. Now today in the centre and north of our country we see KNMi stations shooting up in temp. From -9 C to 0 C in a matter of an hour. First people thought it was an error, but soon others followed. All above zero. Not in my regio. One reason: no wind. No wind meant -15 to localy -21 C. But it also means plus degrees. So we have Hupsel at +1.7 C and Twenthe, just 20 miles NE under the very same local conditions but with a little wind at -2,8 C.
What have we witnessed: KNMI removing at least some of the exceptional values. I checked it and the KNMI has three screens operating at the Bilt and all showed a similar rise with the 0,0 C value sitting right in between. My suspiscion: they have corrected here due to radiation errors.
Now interestingly at Silvolde we have a Davis that registered -2,8 C and a Barani at the same field that registered -3,8 C. Silvolde is close to Hupsel. It has a little wind (1 m/s). But it seems we seen the problems with radiation errors now: very clear sky, no wind and lots of snow...
I also noted a KNMI station at De Bilt named KNMI LoRa...It is not in use currently, but what could that be? May be...?
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I haven't post on here in some time but i decided to try testing how the height of the sensor placement in the shield might make a difference in performance of the Pro shield. I am comparing it to my Young 43502 shield. Both sensors are the sht 31 and have been calibrated to match each other and the shields are co-located on my weather tower at the same height. First results with wind blowing all night both shields read the same low temp of 56.3 and with the sunshine this morning and still good wind blowing the Pro has been running about .4F lower than the Young. Now i need a calm wind day with sunshine to see how The Pro with the repositioned sensor holds up against the Young. I have high solar here in South Texas at a lat. of 27.8 degrees and no snow problems so readings are over grass.
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A quick update, winds were blowing today and mostly sunny with some clouds in the afternoon and surprisingly the Pro was running 1.3 degrees lower than the Young shield and when a cloud moved over the Young temp dropped down to the Pro temp and went back up with the return of the sun. Now which is right, so i put my Davis 24 hour shield back out and calibrated to match the other two. It is supposed to be sunny tomorrow and i will get to see if the Young is reading high compared to the Pro and the Davis shields.
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It is good to see you back. I have been thinking about getting the Barani shield.