Author Topic: Barani pro passive shield  (Read 8871 times)

0 Members and 1 Guest are viewing this topic.

Offline jgentry

  • Forecaster
  • *****
  • Posts: 365
Re: Barani pro passive shield
« Reply #200 on: October 12, 2018, 12:26:39 PM »
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 donít 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
Davis Vantage Pro2. SHT-75. WU: KXALJEMI2 & KALTHORS2. CWOP/APRS: C6353 & E6358

  

Offline ValentineWeather

  • Forecaster
  • *****
  • Posts: 5542
Re: Barani pro passive shield
« Reply #201 on: October 12, 2018, 01:08:26 PM »
I'm seeing less need for FARS also as we are in fall mode even relative calm windless days. 

Randy

Offline jgentry

  • Forecaster
  • *****
  • Posts: 365
Re: Barani pro passive shield
« Reply #202 on: October 14, 2018, 05:20:54 PM »
Where my station is located (in an enclosed area) itís 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 stationís recorded highs are typically around 1-2į cooler than my highs.

But Iím thinking my station at my house deals with a lack of ďmixingĒ 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. Iíve seen as much as .3į jump in temp and 4-5% in RH per update cycle. Then again, Iím sure part of that is due to the 75.
Davis Vantage Pro2. SHT-75. WU: KXALJEMI2 & KALTHORS2. CWOP/APRS: C6353 & E6358

  

Offline jgentry

  • Forecaster
  • *****
  • Posts: 365
Re: Barani pro passive shield
« Reply #203 on: October 14, 2018, 09:55:41 PM »
I will say that insects are still crawling on the shield like they donít give a flip. Lol
Davis Vantage Pro2. SHT-75. WU: KXALJEMI2 & KALTHORS2. CWOP/APRS: C6353 & E6358

  

Offline ValentineWeather

  • Forecaster
  • *****
  • Posts: 5542
Re: Barani pro passive shield
« Reply #204 on: October 14, 2018, 10:18:26 PM »
I will say that insects are still crawling on the shield like they donít give a flip. Lol

Same here I had ants trailing on mine...
Randy

Offline ValentineWeather

  • Forecaster
  • *****
  • Posts: 5542
Re: Barani pro passive shield
« Reply #205 on: October 15, 2018, 01:53:37 PM »
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 3-4į 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 37į.
 [ You are not allowed to view attachments ]

 [ You are not allowed to view attachments ]
 [ You are not allowed to view attachments ]

Randy

Offline dendrite

  • Forecaster
  • *****
  • Posts: 360
Re: Barani pro passive shield
« Reply #206 on: October 15, 2018, 02:07:25 PM »
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.

Offline dendrite

  • Forecaster
  • *****
  • Posts: 360
Re: Barani pro passive shield
« Reply #207 on: October 15, 2018, 02:12:00 PM »
Actually your standard has all white plates, correct? Or did you paint the underside a flat black?

Offline ValentineWeather

  • Forecaster
  • *****
  • Posts: 5542
Re: Barani pro passive shield
« Reply #208 on: October 15, 2018, 02:14:14 PM »
I painted the inside on standard flat brown to reduce glare.
Randy

Offline ValentineWeather

  • Forecaster
  • *****
  • Posts: 5542
Re: Barani pro passive shield
« Reply #209 on: October 15, 2018, 03:30:37 PM »
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.
 [ You are not allowed to view attachments ]
 [ You are not allowed to view attachments ]
 
« Last Edit: October 16, 2018, 05:20:02 AM by ValentineWeather »
Randy

Offline ValentineWeather

  • Forecaster
  • *****
  • Posts: 5542
Re: Barani pro passive shield
« Reply #210 on: October 15, 2018, 09:28:15 PM »
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.
 [ You are not allowed to view attachments ]
Randy

Offline ValentineWeather

  • Forecaster
  • *****
  • Posts: 5542
Re: Barani pro passive shield
« Reply #211 on: October 16, 2018, 12:55:20 PM »
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.
Randy

Offline jgentry

  • Forecaster
  • *****
  • Posts: 365
Re: Barani pro passive shield
« Reply #212 on: October 17, 2018, 09:36:28 PM »
IMO: Itís false advertising from Barani to say that insects and spiders donít like your shield. Already had a spider built a web on the shield and laid some eggs on the black louver...
Davis Vantage Pro2. SHT-75. WU: KXALJEMI2 & KALTHORS2. CWOP/APRS: C6353 & E6358

  

Offline mauro63

  • Senior Member
  • **
  • Posts: 50
Re: Barani pro passive shield
« Reply #213 on: October 26, 2018, 10:02:34 AM »
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  ;)

 [ You are not allowed to view attachments ]
 [ You are not allowed to view attachments ]
 [ You are not allowed to view attachments ]
 [ You are not allowed to view attachments ]

yesterday graph comparision, clear, low wind and about 550w/mq solar radiation

 [ You are not allowed to view attachments ]

Mauro

Offline ValentineWeather

  • Forecaster
  • *****
  • Posts: 5542
Re: Barani pro passive shield
« Reply #214 on: October 26, 2018, 11:02:03 AM »
Did you include the insulating sleeve?


https://www.scaledinstruments.com/wp-content/uploads/2014/09/24hr_fars_Exploded_Diagram.pdf

 [ You are not allowed to view attachments ]
Randy

Offline mauro63

  • Senior Member
  • **
  • Posts: 50
Re: Barani pro passive shield
« Reply #215 on: October 26, 2018, 11:59:00 AM »
Did you include the insulating sleeve?


https://www.scaledinstruments.com/wp-content/uploads/2014/09/24hr_fars_Exploded_Diagram.pdf

 [ You are not allowed to view attachments ]

no randy, I did not do it, this is only first test, I think I will do a lot of improvement
Mauro

Offline mauro63

  • Senior Member
  • **
  • Posts: 50
Re: Barani pro passive shield
« Reply #216 on: October 26, 2018, 12:46:35 PM »
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

 [ You are not allowed to view attachments ]

Offline mauro63

  • Senior Member
  • **
  • Posts: 50
Re: Barani pro passive shield
« Reply #217 on: October 27, 2018, 03:57:49 PM »
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
 ;)

 [ You are not allowed to view attachments ]

Offline Ken7

  • Member
  • *
  • Posts: 45
Re: Barani pro passive shield
« Reply #218 on: November 15, 2018, 06:48:13 AM »
...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.

Iíve got the FARS 6323 sensor array (about 6 months old) and Iím curious what youíre referencing with the Ďmoveí you say that Davis pulled with RH. My readings seem on target, but perhaps Iím not aware of some issue. Are you saying their RH specs are off?
« Last Edit: November 15, 2018, 06:56:10 AM by Ken7 »

Offline jgentry

  • Forecaster
  • *****
  • Posts: 365
Re: Barani pro passive shield
« Reply #219 on: November 17, 2018, 05:07:35 PM »
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.
 [ You are not allowed to view attachments ]

What did Jan say about your temperature issues with snow cover?
Davis Vantage Pro2. SHT-75. WU: KXALJEMI2 & KALTHORS2. CWOP/APRS: C6353 & E6358

  

Offline ValentineWeather

  • Forecaster
  • *****
  • Posts: 5542
Re: Barani pro passive shield
« Reply #220 on: November 17, 2018, 06:57:20 PM »
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.
 [ You are not allowed to view attachments ]

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.
Randy

Offline jgentry

  • Forecaster
  • *****
  • Posts: 365
Re: Barani pro passive shield
« Reply #221 on: November 18, 2018, 05:23:12 PM »
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.
 [ You are not allowed to view attachments ]

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. Youíre 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? Iím believing that the black louvers are increasing the error of temperature readings during calm wind conditions.
Davis Vantage Pro2. SHT-75. WU: KXALJEMI2 & KALTHORS2. CWOP/APRS: C6353 & E6358

  

Offline openvista

  • Forecaster
  • *****
  • Posts: 423
    • marquetteweather.com
Re: Barani pro passive shield
« Reply #222 on: November 18, 2018, 06:05:24 PM »
...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.

Iíve got the FARS 6323 sensor array (about 6 months old) and Iím curious what youíre referencing with the Ďmoveí you say that Davis pulled with RH. My readings seem on target, but perhaps Iím 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

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. 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.
Davis Vantage Pro2 FARS | https://marquetteweather.com | EW7933

Offline Ken7

  • Member
  • *
  • Posts: 45
Re: Barani pro passive shield
« Reply #223 on: November 18, 2018, 08:44:59 PM »

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

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. 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.

Offline openvista

  • Forecaster
  • *****
  • Posts: 423
    • marquetteweather.com
Re: Barani pro passive shield
« Reply #224 on: November 18, 2018, 11:45:09 PM »

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

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. 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). 
Davis Vantage Pro2 FARS | https://marquetteweather.com | EW7933

 

anything