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Weather Station Hardware => Davis Instruments Weather Stations => Topic started by: ValentineWeather on July 27, 2018, 06:40:45 AM

Title: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on July 27, 2018, 06:40:45 AM
Never thought I would become an advocate of a passive shield over FARS but yesterday I started testing the passive 7714 vs 24 hr. FARS and just the first day under clear sky and light winds the 7714 ran .5 to 1 lower than the FARS all day never having  afternoon spike like so many passive shields I've tested before did. I modified my shield with interior floor and roof painted flat black.

This is an inexpensive shield is why I'm excited and no moving parts.
 
The WMO did a study 2008-2009 using reference instruments. The passive 7714 actually got the highest 5 star rating and was cooler than reference and beat out the Davis FARS under light winds sunny conditions.

PDF of full study:  https://www.wmo.int/pages/prog/www/IMOP/publications/IOM-106_Ghardaia/IOM-106_Report.pdf

SDAVIS are the 2 passive 7714  and VDAVIS are the two FARS units tested.  0 is reference, you can see both performed well but most impressive the 7714 did better which confirms what I saw yesterday.

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These are the test summaries of both shields. Low wind the FARS did well but warmer than reference when wind came up and got a 3 star rating. The passive performed well all areas and got a 5 star rating.

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Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: Old Tele man on July 27, 2018, 09:18:27 AM
Thanks for posting that! VERY applicable testing & analyses to people (like me) living in desert locations.

However, I would change this statement from the (8 plate) Davis 07714 booklet: "The radiation shield allows the temperature sensor to accurately measure air temperature without the effects of direct radiation from sunlight."

to this: "The radiation shield allows the temperature sensor to accurately measure air temperature without by mitigating the effects of direct radiation from sunlight."

Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: jgentry on July 27, 2018, 09:27:33 AM
Interesting. But would there still be some lag time with that passive shield?
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: Old Tele man on July 27, 2018, 09:33:05 AM
Interesting. But would there still be some lag time with that passive shield?
Smaller material volume means less HEAT buildup (and retension) as well as less material surface area acting like car radiator heating the incoming air. The more material the quicker the sun heat is captured and thus quicker to transfer more heat (larger radiator) into the incoming air; less material is opposite effect.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: dendrite on July 27, 2018, 09:38:30 AM
I had the 7714 back in my WMII days. Then I got the Davis cabled FARS when that was a shiny and new product. The results were night and day for me. Way more response and cooler temps with the FARS. I'm glad you're happy with it, but I won't be going passive any time soon.

Do you have a pic showing them all setup together?
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: openvista on July 27, 2018, 10:14:19 AM
OK, I just snagged the last 7714 in stock from Ryan. Gonna run this as my passive shield backup. I'll put a wet 31 sensor in there and see how temps perform. I will be SHOCKED if this thing can run neck and neck with my FARS with the AC fan inside long term.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: openvista on July 27, 2018, 10:17:03 AM
Smaller material volume means less HEAT buildup (and retension) as well as less material surface area acting like car radiator heating the incoming air. The more material the quicker the sun heat is captured and thus quicker to transfer more heat (larger radiator) into the incoming air; less material is opposite effect.

If anything the 7714 with its 3 extra plates that are 1" longer than the stock Davis shield would present more thermal mass. It would seem the "magic" lies elsewhere... but where?

EDIT: I get now that you're comparing it to the FARS shield, but I still can't figure out how it outperforms the default passive shield (7710).
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: ValentineWeather on July 27, 2018, 10:19:14 AM
Just finished switch over on remote station.  The study does show it's a great shield and my 1 day of testing seemed to confirm with no afternoon heat spike that has always made me stay away from passive shields. 

For now I'll just update this thread with a few daily graphs with no bias. I love accuracy so no bias, I'm as curious as the next and always thought fars was the way to go.

One thing I noticed in the study the Davis FARS was tagged as having a cool bias over reference shield in certain conditions and warm bias in others while the passive was same 97-99% of time. Anyone wondering how fast reaction time on temperature changes it scored well in testing.

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Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: ValentineWeather on July 27, 2018, 10:26:30 AM
OK, I just snagged the last 7714 in stock from Ryan. Gonna run this as my passive shield backup. I'll put a wet 31 sensor in there and see how temps perform. I will be SHOCKED if this thing can run neck and neck with my FARS with the AC fan inside long term.

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Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: dendrite on July 27, 2018, 10:46:19 AM
Heh. You have some wide open fields there. Maybe it would work for you with that much ventilation. No such luck at my place with all of the trees surrounding my yard. I'm lucky to get a 10mph gust on a fair weather summer day.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: kcidwx on July 27, 2018, 10:49:31 AM
My daughters WMII temperature/humidity sensor has been in the 7714 for about 20 months. My Nimbus temperature probe is in a RM Young FARS a few feet away. I lab test both sensors every 12 months to check calibration. Looking at both of our 1-minute data over the last 20 months, her WMII under sunny/calm wind conditions has never been any higher than 1.8F above my temperature sensor. She's been as low as 1.9F below my temperature sensor at night.

In looking over the data, I've seen instances where she's been 3F to 4F above me. However, this was always right after a frontal passage where the temperature dropped significantly and that exposed some lag in her readings. Once the temperature stabilized, it was within 1F of me again. I actually found one instance where we dropped 15F in 10 minutes and she was 7F above me for a brief period of time.

I would never trade a FARS for a passive shield when it comes to temperature. However, if for whatever reason you want a passive shield, then the 7714 is the way to go. I've not tested one that works any better than the 7714.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: dendrite on July 27, 2018, 10:51:54 AM
The thing with the higher RH with the passive at night...

I generally noticed cooler temps with mins via radiational cooling with the passive since the shield and sensor experience some heat loss. Without forced air coming through, maybe it reaches condensation a little easier on the sensor.

The FARS is going to keep forcing air through there which increases the evaporation rate on the sensor/PCB and inhibits condensation trying to form.

It'd be interesting if you had a 75 in the passive shield. You'd probably gain any response time that you lost with the 31 + FARS combo.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: openvista on July 27, 2018, 11:11:06 AM
I can see how passive would work out well in an open field (like the one pictured above) or in a well-ventilated back yard. However, we get so many low wind days/nights here in town, especially during the summer, that it might be tough for any passive shield to compete with my FARS.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: ValentineWeather on July 27, 2018, 11:13:14 AM
I think the only way to properly test is having matching thermometers. These SHT31's are all the same within .1F  but
if anyone wants to follow this Davis station with 7714 pictured above and airport ASOS I'll add links with 5 minute updates.


links with 5 minute updates about 2 miles distance.

https://mesowest.utah.edu/cgi-bin/droman/meso_base_dyn.cgi?stn=E7498
https://mesowest.utah.edu/cgi-bin/droman/meso_base_dyn.cgi?stn=KVTN&unit=0&timetype=LOCAL/

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Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: Old Tele man on July 27, 2018, 11:24:19 AM
Randy, do you visit Dr Steve Dimse's findU weather site? There, you can overlay selected local sites (yes, more than one) over your plots. For example, here's my DW6988 (blue) overlaid with local Marana airport KVAQ (purple):

https://weather.gladstonefamily.net/qchart/D6988?date=20180727&addnl=KAVQ&Add+to+charts=Add+to+charts&.cgifields=addnl (https://weather.gladstonefamily.net/qchart/D6988?date=20180727&addnl=KAVQ&Add+to+charts=Add+to+charts&.cgifields=addnl)

Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: dendrite on July 27, 2018, 11:25:40 AM
Of course your local ASOS, that you're comparing to, is pumping the air through the sensor chamber too so the FARS really shouldn't be considered the root of the problem. It still goes back to the Davis sensor. If you're getting readings you like with the passive shield though then I guess the workaround works for you with your setup. It would still be nice to get the readings to jive with the FARS installed.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: openvista on July 27, 2018, 11:33:34 AM
Of course your local ASOS, that you're comparing to, is pumping the air through the sensor chamber too so the FARS really shouldn't be considered the root of the problem. It still goes back to the Davis sensor. If you're getting readings you like with the passive shield though then I guess the workaround works for you with your setup. It would still be nice to get the readings to jive with the FARS installed.

If the "problem" you're referring to is humidity measurement, the airport does not aspirate their humidity sensor. It's only minimally shielded from the elements, not contained within a standard radiation shield.

EDIT: I got that info from Ron (kcidwx) in the other thread about psychrometers and SHT31 humidity problems. However, in looking at the Wikipedia page for AWOS (https://en.wikipedia.org/wiki/Automated_airport_weather_station#Temperature_and_dew_point (https://en.wikipedia.org/wiki/Automated_airport_weather_station#Temperature_and_dew_point)), it appears the modern systems use a radiation shield, just not, perhaps, aspirated.

Randy can correct me if I'm wrong, but I think he's just trying to establish temperature accuracy before tearing down his existing aspirated shields and replacing them with the 7714.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: dendrite on July 27, 2018, 11:50:49 AM
Of course your local ASOS, that you're comparing to, is pumping the air through the sensor chamber too so the FARS really shouldn't be considered the root of the problem. It still goes back to the Davis sensor. If you're getting readings you like with the passive shield though then I guess the workaround works for you with your setup. It would still be nice to get the readings to jive with the FARS installed.

If the "problem" you're referring to is humidity measurement, the airport does not aspirate their humidity sensor. It's only minimally shielded from the elements, not contained within a standard radiation shield.

Randy can correct me if I'm wrong, but I think he's just trying to establish temperature accuracy before tearing down his existing aspirated shields and replacing them with the 7714.

EDIT: I should probably clarify that it's the dew point sensor that is minimally shielded and humidity is derived from that.
True. Of course the Vaisala sensor is artificially heated to completely prevent condensation from forming on it. Then they have their algorithms to produce a fairly accurate Td. The whole topic has my brain spinning in circles and my migraine doesn't help.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: hwcorder on July 27, 2018, 01:32:26 PM
Has anyone else tested one of these?

https://www.baranidesign.com/meteoshield-professional/

I've had mine in for about three days and happy with the results. Stats from MADIS have held about the same compared to ASOS station close to me and the last two days have been mostly sunny and fairly light wind. The shield is expensive for a passive and definitely more than the 7714. It's supposedly designed to protect the sensor from contamination in the way airflow is directed inside the chamber.
Edit: Forgot to add you will have to do some engineering to get the Davis sensor to fit.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: openvista on July 27, 2018, 01:36:03 PM
Has anyone else tested one of these?

https://www.baranidesign.com/meteoshield-professional/

I've had mine in for about three days and happy with the results. Stats from MADIS have held about the same compared to ASOS station close to me and the last two days have been mostly sunny and fairly light wind. The shield is expensive for a passive and definitely more than the 7714. It's supposedly designed to protect the sensor from contamination in the way airflow is directed inside the chamber.

My problem with it is it's designed for a probe sensor and is completely open at the bottom letting in reflected radiation. I'm thinking of snow albedo and longwave radiation at night, in particular. Plus, isn't it something like $500 just for the shield?
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: Old Tele man on July 27, 2018, 01:57:00 PM
Has anyone else tested one of these?

https://www.baranidesign.com/meteoshield-professional/

I've had mine in for about three days and happy with the results. Stats from MADIS have held about the same compared to ASOS station close to me and the last two days have been mostly sunny and fairly light wind. The shield is expensive for a passive and definitely more than the 7714. It's supposedly designed to protect the sensor from contamination in the way airflow is directed inside the chamber.

My problem with it is it's designed for a probe sensor and is completely open at the bottom letting in reflected radiation. I'm thinking of snow albedo and longwave radiation at night, in particular. Plus, isn't it something like $500 just for the shield?

The Davis #07714 has a closed bottom shield plate and was only $54.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: ValentineWeather on July 27, 2018, 02:09:53 PM
Randy, do you visit Dr Steve Dimse's findU weather site? There, you can overlay selected local sites (yes, more than one) over your plots. For example, here's my DW6988 (blue) overlaid with local Marana airport KVAQ (purple):

https://weather.gladstonefamily.net/qchart/D6988?date=20180727&addnl=KAVQ&Add+to+charts=Add+to+charts&.cgifields=addnl (https://weather.gladstonefamily.net/qchart/D6988?date=20180727&addnl=KAVQ&Add+to+charts=Add+to+charts&.cgifields=addnl)

Nice thanks.

Yes the 7714 are completely closed on bottom someone was a genius when designing or just got really lucky.   :grin:
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: openvista on July 27, 2018, 02:14:16 PM
OK, so doing a bit of research into reference humidity measurement and stumbled onto user's manual from All Weather Inc., the manufacturer of the AWOS system. It mentions using an *optional* aspirated shield for measuring humidity. See: http://www.allweatherinc.com/wp-content/uploads/5190-C-0011.pdf (http://www.allweatherinc.com/wp-content/uploads/5190-C-0011.pdf). I'm 99.9% sure this sensor is used ONLY for measuring humidity as temperature measurement occurs in a different shield and requires fan aspiration.

Also interesting is that at -20C (-4F) it's max humidity reading is down to 81%.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: ValentineWeather on July 27, 2018, 02:15:53 PM
Has anyone else tested one of these?

https://www.baranidesign.com/meteoshield-professional/

I've had mine in for about three days and happy with the results. Stats from MADIS have held about the same compared to ASOS station close to me and the last two days have been mostly sunny and fairly light wind. The shield is expensive for a passive and definitely more than the 7714. It's supposedly designed to protect the sensor from contamination in the way airflow is directed inside the chamber.
Edit: Forgot to add you will have to do some engineering to get the Davis sensor to fit.

Can you get the SHT31 inside?  I was going to be involved with testing these but they never got back after I gave them all information.

I made the mistake of posting a thread here and had a few negative post about persons with no interest in a passive shield and never heard back from them again. 
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: openvista on July 27, 2018, 02:22:19 PM
Has anyone else tested one of these?

https://www.baranidesign.com/meteoshield-professional/

I've had mine in for about three days and happy with the results. Stats from MADIS have held about the same compared to ASOS station close to me and the last two days have been mostly sunny and fairly light wind. The shield is expensive for a passive and definitely more than the 7714. It's supposedly designed to protect the sensor from contamination in the way airflow is directed inside the chamber.

My problem with it is it's designed for a probe sensor and is completely open at the bottom letting in reflected radiation. I'm thinking of snow albedo and longwave radiation at night, in particular. Plus, isn't it something like $500 just for the shield?

The Davis #07714 has a closed bottom shield plate and was only $54.

See bolded & enlarged part of quote.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: openvista on July 27, 2018, 02:26:49 PM
Has anyone else tested one of these?

https://www.baranidesign.com/meteoshield-professional/

I've had mine in for about three days and happy with the results. Stats from MADIS have held about the same compared to ASOS station close to me and the last two days have been mostly sunny and fairly light wind. The shield is expensive for a passive and definitely more than the 7714. It's supposedly designed to protect the sensor from contamination in the way airflow is directed inside the chamber.
Edit: Forgot to add you will have to do some engineering to get the Davis sensor to fit.

Can you get the SHT31 inside?  I was going to be involved with testing these but they never got back after I gave them all information.

I made the mistake of posting a thread here and had a few negative post about persons with no interest in a passive shield and never heard back from them again.

They quietly pulled their development of their VP2 compatible shield. They were trying to use a probe and couldn't get it connected to the SIM. My guess is Davis won't sell their sensors to a competitor so they tried their own solution and couldn't get it to work.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: ValentineWeather on July 27, 2018, 02:37:42 PM
Has anyone else tested one of these?

https://www.baranidesign.com/meteoshield-professional/

I've had mine in for about three days and happy with the results. Stats from MADIS have held about the same compared to ASOS station close to me and the last two days have been mostly sunny and fairly light wind. The shield is expensive for a passive and definitely more than the 7714. It's supposedly designed to protect the sensor from contamination in the way airflow is directed inside the chamber.
Edit: Forgot to add you will have to do some engineering to get the Davis sensor to fit.

Can you get the SHT31 inside?  I was going to be involved with testing these but they never got back after I gave them all information.

I made the mistake of posting a thread here and had a few negative post about persons with no interest in a passive shield and never heard back from them again.

They quietly pulled their development of their VP2 compatible shield. They were trying to use a probe and couldn't get it connected to the SIM. My guess is Davis won't sell their sensors to a competitor so they tried their own solution and couldn't get it to work.

I see.  :-(   I spent time with them sent images measurements etc. and never heard back after the initial first couple weeks.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: hwcorder on July 27, 2018, 03:18:48 PM
Has anyone else tested one of these?

https://www.baranidesign.com/meteoshield-professional/

I've had mine in for about three days and happy with the results. Stats from MADIS have held about the same compared to ASOS station close to me and the last two days have been mostly sunny and fairly light wind. The shield is expensive for a passive and definitely more than the 7714. It's supposedly designed to protect the sensor from contamination in the way airflow is directed inside the chamber.

My problem with it is it's designed for a probe sensor and is completely open at the bottom letting in reflected radiation. I'm thinking of snow albedo and longwave radiation at night, in particular. Plus, isn't it something like $500 just for the shield?

The only opening on the bottom is for a probe type opening. Like I said you have to do some engineering to get a Davis to work. This is actually kind of a double shield with the outer being white and the inner being black to protect against longwave radiation loss at nigh

Seems like I saw a test somewhere where they compared this shield over a snowpack and it outperformed some FARS units. Will have to see if I can find it though.
As far as pricing I think I got it for around $250.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: openvista on July 27, 2018, 03:22:05 PM
More AWOS goodness. This is from another All Weather Inc. document seen here: http://www.allweatherinc.com/wp-content/uploads/AWOS-III-PTHU-Specification-1505220-16-Latest-Edition1.pdf (http://www.allweatherinc.com/wp-content/uploads/AWOS-III-PTHU-Specification-1505220-16-Latest-Edition1.pdf)

Quote
The relative humidity sensor shall be
thermally  isolated  in  a  motor  aspirat
ed  radiation  shield
  to  accurately 
measure the atmospheric
dew point temperature.

This is for the AWOS III P/T which is used at my local airport KSAW.

So if the reason for investigating passive shields is because fan aspiration is not "best practice" for humidity measurement, this may not be completely true. Also consider that many highly accurate analog psychrometers now use aspiration. Plus, consider the research concluding that passive shields create an artificially wet environment in low wind situations.

Unfortunately, there's no perfect solution. I can certainly appreciate the "wear & tear" consideration on sensors subjected to extra air and moisture crossing them due to active ventilation, especially if your sensors can be adequately passively ventilated. In the end, I suppose we all choose according to our unique priorities.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: kcidwx on July 27, 2018, 03:24:52 PM
Here, I took a couple photos of the ASOS DTS1 sensor/shield. The weeds are gone now but my allergies aren't  :lol:

(https://farm1.staticflickr.com/860/41869017750_ab6c6910f7_b.jpg)

(https://farm1.staticflickr.com/859/41869006820_57f6624235_b.jpg)
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: hwcorder on July 27, 2018, 03:28:42 PM
Has anyone else tested one of these?

https://www.baranidesign.com/meteoshield-professional/

I've had mine in for about three days and happy with the results. Stats from MADIS have held about the same compared to ASOS station close to me and the last two days have been mostly sunny and fairly light wind. The shield is expensive for a passive and definitely more than the 7714. It's supposedly designed to protect the sensor from contamination in the way airflow is directed inside the chamber.
Edit: Forgot to add you will have to do some engineering to get the Davis sensor to fit.

Can you get the SHT31 inside?  I was going to be involved with testing these but they never got back after I gave them all information.

I made the mistake of posting a thread here and had a few negative post about persons with no interest in a passive shield and never heard back from them again.

They quietly pulled their development of their VP2 compatible shield. They were trying to use a probe and couldn't get it connected to the SIM. My guess is Davis won't sell their sensors to a competitor so they tried their own solution and couldn't get it to work.

I'm planning on making my own probe using a magic marker casing a 4pin connector and an sht75. Will also get a filter from Campbell scientific or Vaisala to put on top.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: openvista on July 27, 2018, 03:29:39 PM
Here, I took a couple photos of the ASOS DTS1 sensor/shield. The weeds are gone now but my allergies aren't  :lol:

OK, just to clarify, this is for an ASOS system? But, apparently, the more modern AWOS's, or some subset of them, aspirate the humidity sensor, at least according to the documentation.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: openvista on July 27, 2018, 03:50:04 PM
My problem with it is it's designed for a probe sensor and is completely open at the bottom letting in reflected radiation. I'm thinking of snow albedo and longwave radiation at night, in particular. Plus, isn't it something like $500 just for the shield?

The only opening on the bottom is for a probe type opening. Like I said you have to do some engineering to get a Davis to work. This is actually kind of a double shield with the outer being white and the inner being black to protect against longwave radiation loss at nigh

Seems like I saw a test somewhere where they compared this shield over a snowpack and it outperformed some FARS units. Will have to see if I can find it though.
As far as pricing I think I got it for around $250.

I stand corrected.

I'll be interested to see what you come up with in the end to mount the 75 in there. It would deserve its own thread. I, too, have been quite curious about whether this shield can live up to the claims.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: ValentineWeather on July 27, 2018, 04:02:55 PM
The ASOS DTS1 humidity sensor sure is exposed for a good air sample.
 
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: kcidwx on July 27, 2018, 04:08:25 PM
Here, I took a couple photos of the ASOS DTS1 sensor/shield. The weeds are gone now but my allergies aren't  :lol:

OK, just to clarify, this is for an ASOS system? But, apparently, the more modern AWOS's, or some subset of them, aspirate the humidity sensor, at least according to the documentation.

Yes, they do. I've worked on the AWOS III-PT. Unless they have done something custom it doesn't use separate sensors for temperature and humidity. It uses a combination 5190-F temperature/humidity sensor inside the 8190 MARS.

Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: openvista on July 27, 2018, 04:29:41 PM
Yes, they do. I've worked on the AWOS III-PT. Unless they have done something custom it doesn't use separate sensors for temperature and humidity. It uses a combination 5190-F temperature/humidity sensor inside the 8190 MARS.

Interesting!

My local airport, KSAW, seems to run about 2-3 degrees low lately in dewpoint as compared to other airports/RAWS stations. Just checked the spec and max error is 3F between +30 and +90F. So, I guess they're within spec!

Do the AWOS IIIP/T capacitive sensors tend to drift noticeably and, if so, which direction is typical?

Also, any idea of the aspiration rate (m/s, cfm, whatever)?
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: dendrite on July 27, 2018, 05:13:29 PM
Nice info in this thread. Thanks guys.


KCID...do you have any spec documentation for the DTS1? I can't find much through Google.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: ValentineWeather on July 27, 2018, 05:22:19 PM
Emailed Ryan about being out of the 7714 he said business has been steady for long time, especially in Canada hard to keep them in stock. Backordered again.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: Old Tele man on July 27, 2018, 05:36:48 PM
Emailed Ryan about being out of the 7714 he said business has been steady for long time, especially in Canada hard to keep them in stock. Backordered again.
Have you tried contacting Bob Ingham at Rainman Weather?
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: ValentineWeather on July 27, 2018, 06:14:09 PM

Have you tried contacting Bob Ingham at Rainman Weather?

No, I'm good for now on shields I was just asking Ryan because few days ago he had more stock in.

Noticed Rainman has the originally Stratus gauge at killer price. $29 + shipping.
Lot's of knockoffs of the gauge now days. Wish someone would make the gauge more accurate and deepen the funnel by couple inches.
That was my first 4" diameter gauge back in 1976.  I think I paid more back then... :roll:
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: openvista on July 27, 2018, 06:18:01 PM
I purchased my first VP2 from Rainman back in the day. I've also gotten some parts here and there from them. Good, fast service. But I see they don't stock the 7714.

If anyone is in a yank, I'd try scientificsales.com (http://scientificsales.com). I've had good luck with them too. I think SS includes shipping in their prices, which is why they seem higher. So don't compare on unit price alone. Shipping just keeps going up and up!
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: CW2274 on July 27, 2018, 06:55:53 PM
Was hosing off my ISS to get some of the dust off of it and got water into the chamber and killed my 67 CFM fan. Ordered another but will take faaar too long to get here, so went and bought one that's "only" 40 CFM from down the street, cause this boy ain't doin' without a fan. Thing's really quiet compared to the other, Ill probably just leave this weaker one in.
GL to all the passive efforts!
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: WxLover16 on July 27, 2018, 08:17:11 PM
Was hosing off my ISS to get some of the dust off of it and got water into the chamber and killed my 67 CFM fan. Ordered another but will take faaar too long to get here, so went and bought one that's "only" 40 CFM from down the street, cause this boy ain't doin' without a fan. Thing's really quiet compared to the other, Ill probably just leave this weaker one in.
GL to all the passive efforts!

If only you had two ISS's to compare to. I wonder how much temp difference there might be between using a 67 and 40cfm fan, if any.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: CW2274 on July 27, 2018, 08:24:42 PM
Was hosing off my ISS to get some of the dust off of it and got water into the chamber and killed my 67 CFM fan. Ordered another but will take faaar too long to get here, so went and bought one that's "only" 40 CFM from down the street, cause this boy ain't doin' without a fan. Thing's really quiet compared to the other, Ill probably just leave this weaker one in.
GL to all the passive efforts!

If only you had two ISS's to compare to. I wonder how much temp difference there might be between using a 67 and 40cfm fan, if any.
I see zero difference, nor did I expect to. 67, although overkill, worked just fine, so will 40, even if it's overkill too. I'll take it.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: ValentineWeather on July 27, 2018, 09:06:17 PM
 I'm removing this graph because I was using a modified shield which was running warmer. Rest of test will include stock shield with fan.

 
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: dendrite on July 27, 2018, 09:46:30 PM
First full day lots of clouds even a thunderstorm with passive once again slightly cooler vs FARS. Couple things morning warm up showed some lag vs FARS red arrow and the fars was more jagged with dew point.  I hate that when we are in high heat index area and it spikes.

 
Looks like it's right in line with the FARS with just a slower response. I see no problem with the jagged dewpoint graph. To each his own though. Pretty sweet performance by the passive though...clouds or not. What did your winds average?
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: ValentineWeather on July 27, 2018, 09:56:01 PM
First full day lots of clouds even a thunderstorm with passive once again slightly cooler vs FARS. Couple things morning warm up showed some lag vs FARS red arrow and the fars was more jagged with dew point.  I hate that when we are in high heat index area and it spikes.

 
Looks like it's right in line with the FARS with just a slower response. I see no problem with the jagged dewpoint graph. To each his own though. Pretty sweet performance by the passive though...clouds or not. What did your winds average?

Thunderstorm peaked into 20's it dropped .24" put mainly went west of town.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: CW7491 on July 28, 2018, 12:48:55 AM
My results with the 7714 compared side by side to the stock 24hr FARS are pretty much right on with ValentineWeather. Maybe its the latitude? Im a FARS fanatic too and almost didnt want to believe it as it seemed counterintuitive.  I went with the 7714 recently because I just moved and my yard presents unique circumstances. The results of the side by side made it easier to swallow.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: ValentineWeather on July 28, 2018, 06:08:03 AM
My results with the 7714 compared side by side to the stock 24hr FARS are pretty much right on with ValentineWeather. Maybe its the latitude? Im a FARS fanatic too and almost didnt want to believe it as it seemed counterintuitive.  I went with the 7714 recently because I just moved and my yard presents unique circumstances. The results of the side by side made it easier to swallow.

I know the feeling. I've always defended and said it's the only way to go and now I'm wondering what's going on.
I've tested passive units before just not this one. The VP2 passive always ran +2 even +3 with light wind speeds. 

Is this correct thinking with tilt of earth summer sun angle is actually more intense northern latitudes vs southern latitudes? If so that can't be an issue on testing.
I know it's different here vs Arizona, sunsets far NW where Arizona it was more west.  Here sunlight is 1+ hours longer also.
I see a 90F day on the 10 day forecast hope wind speeds are light.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: jerryg on July 28, 2018, 10:39:47 AM
Something i have been wondering is i have read a lot about the inside of shields being painted black to absorb radiation inside of the shield and white on the outside to reflect the solar effect. Most of the studies show a positive effect so why aren't more of the shields on the market made that way? The only reason i can think of is cost?
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: ValentineWeather on July 28, 2018, 10:54:39 AM
I see more now flat black on inside, even the single probe gill shields.  I think it came from a study WMO did some years back showing the benefit. They even tested Stevenson screens with white and black interiors. Black always had less error because the flat black reduces heat reflection by absorbing it, I believe was how it was explained.   
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: jerryg on July 28, 2018, 11:14:45 AM
It just seems to me to make good sense that you would want to reflect all the solar energy you could be fore it gets inside and absorb all you could before it gets to the sensor instead of having it white inside and bouncing all that heat around in the chamber.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: Old Tele man on July 28, 2018, 12:58:03 PM
The insides of ALL optical devices (cameras, binoculars, telescopes, etc.) are painted flat black to absorb and de-scatter stray light, which includes long wavelength infrared where the heat is.

The protocol for ALL optical and thermal sensing devices used at USArmy Yuma Proving Ground is shiny WHITE/top surfaces with flat BLACK/bottom surfaces.

That's how my solar shields are now, however, there IS a caveat, not all white paints are 100% reflective and not all black paints are 100% absorptive...AND, some paints want to dissolve/eat the plastic plates (depends on the plastic). For now, I'm using Rustoleum Flat Black and Gloss White...but I'm interested to hear what others use.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: jerryg on July 28, 2018, 01:11:50 PM
I haven't played with black yet but i used  Rust. flat white paint made for plastic and uv resistant. I am not sure how you tell if black will be absorbent or not, just thought black would absorb being black and all lol. Need a paint guru to chime in here. :???:
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: ValentineWeather on July 28, 2018, 01:27:34 PM
I'm starting this test over today because the first day shield being used was modified with bottom removed so I could insert another sensor inside.

I believe this was allowing reflective heat waves inside sensor chamber causing a slight warming. I went back to stock shield with AC fan today. I'm currently seeing FARS running .3 to .5 F cooler with completely stock shield. Still not bad for passive but will need to continue testing.
 [ You are not allowed to view attachments ]
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: SnowHiker on July 28, 2018, 02:44:18 PM
I haven't played with black yet but i used  Rust. flat white paint made for plastic and uv resistant. I am not sure how you tell if black will be absorbent or not, just thought black would absorb being black and all lol. Need a paint guru to chime in here. :???:
Not a paint guru, so I'll just state what's probably more or less obvious.  If you paint the inside of your shield you better give the paint plenty of time to dry before putting the sensor in, as there seems to already be a lot of concern about contamination.  Also I would be a little concerned about the paint, especially if low quality, eventually flaking and turning to dust, even though not in direct sunlight, possibly causing more problems.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: Old Tele man on July 28, 2018, 02:55:07 PM
I haven't played with black yet but i used  Rust. flat white paint made for plastic and uv resistant. I am not sure how you tell if black will be absorbent or not, just thought black would absorb being black and all lol. Need a paint guru to chime in here. :???:
Not a paint guru, so I'll just state what's probably more or less obvious.  If you paint the inside of your shield you better give the paint plenty of time to dry before putting the sensor in, as there seems to already be a lot of concern about contamination.  Also I would be a little concerned about the paint, especially if low quality, eventually flaking and turning to dust, even though not in direct sunlight, possibly causing more problems.
Absolutely, 'out-gassing' of paint volatile's will detrimentally affect RH sensor accuracy.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: kcidwx on July 28, 2018, 03:03:29 PM
Yes, they do. I've worked on the AWOS III-PT. Unless they have done something custom it doesn't use separate sensors for temperature and humidity. It uses a combination 5190-F temperature/humidity sensor inside the 8190 MARS.

Interesting!

My local airport, KSAW, seems to run about 2-3 degrees low lately in dewpoint as compared to other airports/RAWS stations. Just checked the spec and max error is 3F between +30 and +90F. So, I guess they're within spec!

Do the AWOS IIIP/T capacitive sensors tend to drift noticeably and, if so, which direction is typical?

Also, any idea of the aspiration rate (m/s, cfm, whatever)?

The 5190 can drift as much as 1% per year and tends to lean on the wet bias side when it does drift. The 8190 MARS aspirates at 360ft/min. The typical problem I see with AWOS systems is the lack of a consistent maintenance schedule.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: kcidwx on July 28, 2018, 03:03:46 PM
Nice info in this thread. Thanks guys.


KCID...do you have any spec documentation for the DTS1? I can't find much through Google.

Relative humidity measurement: Measurement range: 0-100%RH; Accuracy at 68F: +-1.0% RH (0-90%RH), +-1.7%RH (90-100%RH); Sensor: Vaisala HUMICAP 180 Vaisala HUMICAP 180R

Accuracy (Including Non-linearity, Hysteresis, and Repeatability)
At +15 ... +25 C (+59 ... +77 F)1 %RH (0 ... 90 %RH)
1.7 %RH (90 ... 100 %RH)
At −20 ... +40 C (−4 ... +104 F) (1.0 + 0.008 reading) %RH
At −40 ... −20 C (−40 ... −4 F) (1.2 + 0.012 reading) %RH
At +40 ... +60 C (+104 ... +140 F)(1.2 + 0.012 reading) %RH
At −60 ... −40 C (−76 ... −40 F)(1.4 + 0.032 reading) %RH


The sensor outputs in DP.

Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: ValentineWeather on July 28, 2018, 03:22:21 PM
I haven't played with black yet but i used  Rust. flat white paint made for plastic and uv resistant. I am not sure how you tell if black will be absorbent or not, just thought black would absorb being black and all lol. Need a paint guru to chime in here. :???:
Not a paint guru, so I'll just state what's probably more or less obvious.  If you paint the inside of your shield you better give the paint plenty of time to dry before putting the sensor in, as there seems to already be a lot of concern about contamination.  Also I would be a little concerned about the paint, especially if low quality, eventually flaking and turning to dust, even though not in direct sunlight, possibly causing more problems.
Absolutely...'out-gassing' of paint volatile's will detrimentally affect RH sensor accuracy.

I thought about that so painted them last week when they first arrived so they had at least 5 days of drying time.  Also open air outside I hope alls well. Did hit 98% on humidity today both stations.

Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: CW2274 on July 28, 2018, 03:29:09 PM
Yes, they do. I've worked on the AWOS III-PT. Unless they have done something custom it doesn't use separate sensors for temperature and humidity. It uses a combination 5190-F temperature/humidity sensor inside the 8190 MARS.

Interesting!

My local airport, KSAW, seems to run about 2-3 degrees low lately in dewpoint as compared to other airports/RAWS stations. Just checked the spec and max error is 3F between +30 and +90F. So, I guess they're within spec!

Do the AWOS IIIP/T capacitive sensors tend to drift noticeably and, if so, which direction is typical?

Also, any idea of the aspiration rate (m/s, cfm, whatever)?
The typical problem I see with AWOS systems is the lack of a consistent maintenance schedule.
I'm sure there are exceptions, but ASOS's are placed at larger airports that handle more passenger traffic than say, at a strictly GA airport and are serviced by NWS or FAA techs. AWOS's are usually at the, as we say, "dink" airports and are "serviced" by airport management.
Like I said, I'm sure one size doesn't fit all.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: Old Tele man on July 28, 2018, 03:49:07 PM
Yes, they do. I've worked on the AWOS III-PT. Unless they have done something custom it doesn't use separate sensors for temperature and humidity. It uses a combination 5190-F temperature/humidity sensor inside the 8190 MARS.

Interesting!

My local airport, KSAW, seems to run about 2-3 degrees low lately in dewpoint as compared to other airports/RAWS stations. Just checked the spec and max error is 3F between +30 and +90F. So, I guess they're within spec!

Do the AWOS IIIP/T capacitive sensors tend to drift noticeably and, if so, which direction is typical?

Also, any idea of the aspiration rate (m/s, cfm, whatever)?
The typical problem I see with AWOS systems is the lack of a consistent maintenance schedule.
I'm sure there are exceptions, but ASOS's are placed at larger airports that handle more passenger traffic than say, at a strictly GA airport and are serviced by NWS or FAA techs. AWOS's are usually at the, as we say, "dink" airports and are "serviced" by airport management.
Like I said, I'm sure one size doesn't fit all.

Yep, I've noticed local airports KVAQ and KRYN exhibit lots of 'questionable' data variability compared to local international airport KTUS and USAF base KDMA...there seldom are agreements in their temp, DP or ALT readings.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: jgentry on July 28, 2018, 04:03:29 PM
I think the only way to properly test is having matching thermometers. These SHT31's are all the same within .1F  but
if anyone wants to follow this Davis station with 7714 pictured above and airport ASOS I'll add links with 5 minute updates.


links with 5 minute updates about 2 miles distance.

https://mesowest.utah.edu/cgi-bin/droman/meso_base_dyn.cgi?stn=E7498
https://mesowest.utah.edu/cgi-bin/droman/meso_base_dyn.cgi?stn=KVTN&unit=0&timetype=LOCAL/

 [ You are not allowed to view attachments ]

See where your 31 went up to 100% today.

So far, the DP is matching up with the Airport
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: graculus on July 28, 2018, 04:22:52 PM
VP2 ISS Upgrade Kit:

7714 shield with SHT-??
Rainwise gauge
Real NEMA enclosure for the ISS electronics board

 ;)
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: ValentineWeather on July 28, 2018, 05:09:52 PM
I think the only way to properly test is having matching thermometers. These SHT31's are all the same within .1F  but
if anyone wants to follow this Davis station with 7714 pictured above and airport ASOS I'll add links with 5 minute updates.


links with 5 minute updates about 2 miles distance.

https://mesowest.utah.edu/cgi-bin/droman/meso_base_dyn.cgi?stn=E7498
https://mesowest.utah.edu/cgi-bin/droman/meso_base_dyn.cgi?stn=KVTN&unit=0&timetype=LOCAL/

 [ You are not allowed to view attachments ]

See where your 31 went up to 100% today.

So far, the DP is matching up with the Airport

 I use Cumulus and can select use 100% for 98%.  They did reach 98% just not 100%. This was in light fog nothing real soupy. I was thinking about the ASOS how sensor is exposed and wonder if that's not also an issue with ours being inside a shield with a filter. 98% may be max in certain environments....Just a :idea:
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: SnowHiker on July 29, 2018, 12:15:00 AM
Flat Black and Gloss White...but I'm interested to hear what others use.
I was wondering about some kind of tape for the black that could be used to line the chamber?  Seems like it would be safer than paint, and easier to remove if needed, depending on the adhesive used.  My first thought was electrical tape, but it would probably be too shiny.  Maybe some kind of gaffer's tape or something?

Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: ValentineWeather on July 29, 2018, 05:23:50 AM
Tape has adhesive on the back which may last much longer. The paint issue is legit concern also, at the time main concern was making the passive shield as good as possible and wasn't planning on putting new sensors in but that has changed now where the passive will be primary shield especially at remote site which is totally wide open with wind movement I have little concern but in town backyard less wind, I still need to test before satisfied.   

Hoping for some calm mostly cloudless hot days ahead for good testing.
Primary concern is sunny calm days I'm not getting max temperature spikes the passive shields are famous for, and so far only .6 which is very acceptable even fars shields 1 difference is common on high temperatures, usually less differential on lows. 
 
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: Bobvelle on July 29, 2018, 01:54:44 PM

Absolutely, 'out-gassing' of paint volatile's will detrimentally affect RH sensor accuracy.
As in Permanently ruin it ?  :shock:
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: DaleReid on July 29, 2018, 02:00:51 PM
Titanium dioxide based white paint, its what they use on the National Solar Observatory Telescope which was on Kitt Peak.

If it is good enough for the research guys, it should be good enough for us.

PS, no idea where they get the stuff.  Maybe an auto paint store which seems to be able to get just about anything might do?
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: Bobvelle on July 29, 2018, 02:01:53 PM
I'm starting this test over today because the first day shield being used was modified with bottom removed so I could insert another sensor inside.

I know we are talking about 2 different shields here but on the 7710, is the recommended mounting location back on the "biscuit disk" hanging from the plate above? I know of three different mount options.. one even uses 1 inch stand-offs. How are you mounting the sensor board?
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: SLOweather on July 29, 2018, 02:02:11 PM
Probably not. As I recall, you can bake the sensor to recondition it. See the Sensirion handling docs and spec sheets.


Absolutely, 'out-gassing' of paint volatile's will detrimentally affect RH sensor accuracy.
As in Permanently ruin it ?  :shock:
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: jgentry on July 29, 2018, 02:02:41 PM
I'm starting this test over today because the first day shield being used was modified with bottom removed so I could insert another sensor inside.

I believe this was allowing reflective heat waves inside sensor chamber causing a slight warming. I went back to stock shield with AC fan today. I'm currently seeing FARS running .3 to .5 F cooler with completely stock shield. Still not bad for passive but will need to continue testing.
 [ You are not allowed to view attachments ]

How is your test turning out?
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: Bobvelle on July 29, 2018, 02:06:29 PM
Titanium dioxide based white paint, its what they use on the National Solar Observatory Telescope which was on Kitt Peak.

If it is good enough for the research guys, it should be good enough for us.

PS, no idea where they get the stuff.  Maybe an auto paint store which seems to be able to get just about anything might do?

TiO2 standard white pigment... Titanium white is the color.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: ValentineWeather on July 29, 2018, 02:21:51 PM
Question asked on mounting it has good options even for multiple sensors if wanted using existing holes with screws.
Testing still in infancy nothing but rain and clouds.

 [ You are not allowed to view attachments ]
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: Bobvelle on July 29, 2018, 02:41:13 PM
Probably not. As I recall, you can bake the sensor to recondition it. See the Sensirion handling docs and spec sheets.


Absolutely, 'out-gassing' of paint volatile's will detrimentally affect RH sensor accuracy.
As in Permanently ruin it ?  :shock:
Thanks, Found it:  (This is for the SHT-15)
1.4 Reconditioning Procedure
As stated above extreme conditions or exposure to solvent
vapors may offset the sensor. The following reconditioning
procedure may bring the sensor back to calibration state:
Baking: 100 105C at < 5%RH for 10h
Re-Hydration: 20 30C at ~ 75%RH for 12h


I wonder how low Rh my oven gets? Likely not <5%. Not in a Gulf Coast region household oven anyway.
.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: SnowHiker on July 29, 2018, 03:13:37 PM
The following reconditioning
procedure may bring the sensor back to calibration state:

Just keep the word "may" in mind. It may bring it back, but then it may not.  Worth a try if the sensor is already contaminated.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: ValentineWeather on July 29, 2018, 03:17:55 PM
Probably not. As I recall, you can bake the sensor to recondition it. See the Sensirion handling docs and spec sheets.


Absolutely, 'out-gassing' of paint volatile's will detrimentally affect RH sensor accuracy.
As in Permanently ruin it ?  :shock:
Thanks, Found it:  (This is for the SHT-15)
1.4 Reconditioning Procedure
As stated above extreme conditions or exposure to solvent
vapors may offset the sensor. The following reconditioning
procedure may bring the sensor back to calibration state:
Baking: 100 105C at < 5%RH for 10h
Re-Hydration: 20 30C at ~ 75%RH for 12h


I wonder how low Rh my oven gets? Likely not <5%. Not in a Gulf Coast region household oven anyway.
.

I used crock pot SLOweather's idea.  I just made a tin foil tent/platform keeping sensor off bottom and baked 10 hours keeping lid cracked open 1/2 to 3/4". Using temperature gun I was between 110-125c. Spark Fun does all sensor baking at 125 even though they say 105c in reconditioning literature.
Some of my sensors only maxed at 96% new baking didn't correct. If sensor reached 98+ new and stopped baking may restore to original performance.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: Bobvelle on July 29, 2018, 03:32:39 PM
Probably not. As I recall, you can bake the sensor to recondition it. See the Sensirion handling docs and spec sheets.


Absolutely, 'out-gassing' of paint volatile's will detrimentally affect RH sensor accuracy.
As in Permanently ruin it ?  :shock:
Thanks, Found it:  (This is for the SHT-15)
1.4 Reconditioning Procedure
As stated above extreme conditions or exposure to solvent
vapors may offset the sensor. The following reconditioning
procedure may bring the sensor back to calibration state:
Baking: 100 105C at < 5%RH for 10h
Re-Hydration: 20 30C at ~ 75%RH for 12h


I wonder how low Rh my oven gets? Likely not <5%. Not in a Gulf Coast region household oven anyway.
.

I used crock pot SLOweather's idea.  I just made a tin foil tent/platform keeping sensor off bottom and baked 10 hours keeping lid cracked open 1/2 to 3/4". Using temperature gun I was between 110-125c. Spark Fun does all sensor baking at 125 even though they say 105c in reconditioning literature.
Some of my sensors only maxed at 96% new baking didn't correct. If sensor reached 98+ new and stopped baking may restore to original performance.

I assume this is the whole assembly? i.e. the PCB and 6c cable attached? If so, what did you do with the cable during baking to keep it of the bottom?
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: openvista on July 29, 2018, 03:54:34 PM
Some of my sensors only maxed at 96% new baking didn't correct. If sensor reached 98+ new and stopped baking may restore to original performance.

Sounds like a mixed bag, at best. But it's good to have someone else attempt it. More data, either way.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: Bobvelle on July 29, 2018, 04:05:30 PM
Some of my sensors only maxed at 96% new baking didn't correct. If sensor reached 98+ new and stopped baking may restore to original performance.

Sounds like a mixed bag, at best. But it's good to have someone else attempt it. More data, either way.

Just to be clear. I'm baking a SHT-11 that's about 5 or 6 years old and hasn't been in use for 2 years. I plan to put in use tomorrow or the next day as a second temp/hum station. If memory serves, it never read over 98% RH. But I wasn't watching for it until I replaced it with my first 31. That 31 would reach 100% RH on only a few occasions, and that was early in it's life.
I may bake it next.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: ValentineWeather on July 29, 2018, 04:22:37 PM
Probably not. As I recall, you can bake the sensor to recondition it. See the Sensirion handling docs and spec sheets.


Absolutely, 'out-gassing' of paint volatile's will detrimentally affect RH sensor accuracy.
As in Permanently ruin it ?  :shock:
Thanks, Found it:  (This is for the SHT-15)
1.4 Reconditioning Procedure
As stated above extreme conditions or exposure to solvent
vapors may offset the sensor. The following reconditioning
procedure may bring the sensor back to calibration state:
Baking: 100 105C at < 5%RH for 10h
Re-Hydration: 20 30C at ~ 75%RH for 12h


I wonder how low Rh my oven gets? Likely not <5%. Not in a Gulf Coast region household oven anyway.
.

I used crock pot SLOweather's idea.  I just made a tin foil tent/platform keeping sensor off bottom and baked 10 hours keeping lid cracked open 1/2 to 3/4". Using temperature gun I was between 110-125c. Spark Fun does all sensor baking at 125 even though they say 105c in reconditioning literature.
Some of my sensors only maxed at 96% new baking didn't correct. If sensor reached 98+ new and stopped baking may restore to original performance.

I assume this is the whole assembly? i.e. the PCB and 6c cable attached? If so, what did you do with the cable during baking to keep it of the bottom?

Cable is attached but leave hanging out. I remove sensor if attached to board that slides into 24 hr. fars sensor chamber and remove filter cap.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: ValentineWeather on July 29, 2018, 04:24:45 PM
Some of my sensors only maxed at 96% new baking didn't correct. If sensor reached 98+ new and stopped baking may restore to original performance.

Sounds like a mixed bag, at best. But it's good to have someone else attempt it. More data, either way.

Yeah if sensor never did reach 98% baking won't help is what I've found.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: Bobvelle on July 29, 2018, 04:37:14 PM
Probably not. As I recall, you can bake the sensor to recondition it. See the Sensirion handling docs and spec sheets.


Absolutely, 'out-gassing' of paint volatile's will detrimentally affect RH sensor accuracy.
As in Permanently ruin it ?  :shock:
Thanks, Found it:  (This is for the SHT-15)
1.4 Reconditioning Procedure
As stated above extreme conditions or exposure to solvent
vapors may offset the sensor. The following reconditioning
procedure may bring the sensor back to calibration state:
Baking: 100 105C at < 5%RH for 10h
Re-Hydration: 20 30C at ~ 75%RH for 12h


I wonder how low Rh my oven gets? Likely not <5%. Not in a Gulf Coast region household oven anyway.
.

I used crock pot SLOweather's idea.  I just made a tin foil tent/platform keeping sensor off bottom and baked 10 hours keeping lid cracked open 1/2 to 3/4". Using temperature gun I was between 110-125c. Spark Fun does all sensor baking at 125 even though they say 105c in reconditioning literature.
Some of my sensors only maxed at 96% new baking didn't correct. If sensor reached 98+ new and stopped baking may restore to original performance.

I assume this is the whole assembly? i.e. the PCB and 6c cable attached? If so, what did you do with the cable during baking to keep it of the bottom?

Cable is attached but leave hanging out. I remove sensor if attached to board that slides into 24 hr. fars sensor chamber and remove filter cap.
Yeah, I thought about that right after I posted, #-o let the cord hang out. I cut a 1 inch length off a paper towel core and ran the cable through it and set the lid on it. It's baking now, but taking a while to get to temp. I remembered too that I have an industrial oven temp meter w/probe that I used for baking Cerakote. Its perfect for this.
Also through some desiccant packs in with it... maybe it will help soak up some humidity.
Thanks for all the Info!
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: jerryg on July 29, 2018, 05:33:45 PM
Well i pulled the trigger on what is supposed to be a really great passive shield from Barani. I am getting the pro and standard shields to compare the two against each other and of course the Davis fars. It sure would be nice to have a passive shield and eliminate the fan and batteries that go with the fars shield. One of the things i will be checking is how the sensor fits into the shields the pro only has an opening of 1.6 inches and the standard has an opening of 2.6 which should allow the sensor to fit. Here is the url to the two shields https://www.allmeteo.com/solar-radiation-shield/
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: SLOweather on July 29, 2018, 05:39:18 PM
Probably not. As I recall, you can bake the sensor to recondition it. See the Sensirion handling docs and spec sheets.


Absolutely, 'out-gassing' of paint volatile's will detrimentally affect RH sensor accuracy.
As in Permanently ruin it ?  :shock:
Thanks, Found it:  (This is for the SHT-15)
1.4 Reconditioning Procedure
As stated above extreme conditions or exposure to solvent
vapors may offset the sensor. The following reconditioning
procedure may bring the sensor back to calibration state:
Baking: 100 105C at < 5%RH for 10h
Re-Hydration: 20 30C at ~ 75%RH for 12h


I wonder how low Rh my oven gets? Likely not <5%. Not in a Gulf Coast region household oven anyway.
.

I used crock pot SLOweather's idea.  I just made a tin foil tent/platform keeping sensor off bottom and baked 10 hours keeping lid cracked open 1/2 to 3/4". Using temperature gun I was between 110-125c. Spark Fun does all sensor baking at 125 even though they say 105c in reconditioning literature.
Some of my sensors only maxed at 96% new baking didn't correct. If sensor reached 98+ new and stopped baking may restore to original performance.

I assume this is the whole assembly? i.e. the PCB and 6c cable attached? If so, what did you do with the cable during baking to keep it of the bottom?

Cable is attached but leave hanging out. I remove sensor if attached to board that slides into 24 hr. fars sensor chamber and remove filter cap.
Yeah, I thought about that right after I posted, #-o let the cord hang out. I cut a 1 inch length off a paper towel core and ran the cable through it and set the lid on it. It's baking now, but taking a while to get to temp. I remembered too that I have an industrial oven temp meter w/probe that I used for baking Cerakote. Its perfect for this.
Also through some desiccant packs in with it... maybe it will help soak up some humidity.
Thanks for all the Info!

FWIW, you should be able to find a site that will calculate absolute humidity (moisture content of the air in er, mass per unit volume, and the use that and the temperature inside the crock pot oven to back calculate the RH in there. :)
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: SLOweather on July 29, 2018, 05:41:41 PM
I used crock pot SLOweather's idea. 

Great... Is that my new nickname around here, Crock Pot SLOweather?

:)
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: ValentineWeather on July 29, 2018, 06:03:51 PM
Well i pulled the trigger on what is supposed to be a really great passive shield from Barani. I am getting the pro and standard shields to compare the two against each other and of course the Davis fars. It sure would be nice to have a passive shield and eliminate the fan and batteries that go with the fars shield. One of the things i will be checking is how the sensor fits into the shields the pro only has an opening of 1.6 inches and the standard has an opening of 2.6 which should allow the sensor to fit. Here is the url to the two shields https://www.allmeteo.com/solar-radiation-shield/

So you think the 2.6" will fit a SHT31? I'm also very interested same reason. I should contact them since we were working together on this originally.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: jerryg on July 29, 2018, 06:15:24 PM
Well it looks like it will by diameter measurement just not sure if the big filter will make it tight. I have looked at a bunch of the sensor boards and it looks like the board could be made smaller by removing the extra to the left of where the shield snaps in, there does not appear to be any circuit printed there and it would come close to fitting in the pro shield with a factory filter which is so much smaller. It sure would be nice to get rid of all the fars stuff and it will be interesting to see how it handles the high humidity problem also.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: ValentineWeather on July 29, 2018, 06:23:10 PM
Well it looks like it will by diameter measurement just not sure if the big filter will make it tight. I have looked at a bunch of the sensor boards and it looks like the board could be made smaller by removing the extra to the left of where the shield snaps in, there does not appear to be any circuit printed there and it would come close to fitting in the pro shield with a factory filter which is so much smaller. It sure would be nice to get rid of all the fars stuff and it will be interesting to see how it handles the high humidity problem also.

I just sent Richard Toth<richard.toth@baranidesign.com>;Jan Barani<jan@baranidesign.com>; email asking if it will fit.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: jerryg on July 29, 2018, 06:45:47 PM
Another nice thing about the shield is your can mount it away from the Davis stuff if you needed to just by using a straight thru jumper and a cat splice. I just made up my new sht75 sensor the other day and made it to fit the pro opening with extra long cable to be able to mount the shield on my tower next to the iss. The 75 has been looking real good in readings and response time. When they get here i will probably use the three 31 sensors because they are nearly identical in temperature readings and that is what the testing is all about, low to no wind and no temp spikes would be great.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: CW2274 on July 29, 2018, 06:47:28 PM
Well i pulled the trigger on what is supposed to be a really great passive shield from Barani. I am getting the pro and standard shields to compare the two against each other and of course the Davis fars.
They were on here when this came out and it looks promising. Thing I don't like is there claim to be as good or better than aspirated shields. Well, what aspirated shields? Just because a PWS has a fan doesn't make a bad shield good, that's for sure. They do do a comparison against an aspirated VP2, but the graph colors are so close together it makes it damn near impossible to distinguish between the two, but I get the point, they're close. That being said, they leave out one tiny little factor, wind speed during the test. :roll: Kinda makes a difference.
Look forward to your comparisons.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: jerryg on July 29, 2018, 07:11:13 PM
It should be interesting to see how they compare against each other as well as the fars. I know when the wind is blowing the standard shield did real well against the fars but as the wind slowed down then the spikes started showing up. It will really be interesting to see how the two compare against each other too. Now all i have to do is sit here a wait for them to show up, that is the hard part lol.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: CW2274 on July 29, 2018, 07:38:41 PM
Now all i have to do is sit here a wait for them to show up, that is the hard part lol.
Yeah, it's been Christmas for a lot of you guys around here, buying stuff left and right, kinda jealous.... Actually, I'm seriously considering picking up a psycho-dyne, as CW7491 has, and see if the drier air here has lessened the wet bias and/or premature aging, as I'm leaning to believe it has.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: Old Tele man on July 29, 2018, 09:57:27 PM
Now all i have to do is sit here a wait for them to show up, that is the hard part lol.
Yeah, it's been Christmas for a lot of you guys around here, buying stuff left and right, kinda jealous.... Actually, I'm seriously considering picking up a psycho-dyne, as CW7491 has, and see if the drier air here has lessened the wet bias and/or premature aging, as I'm leaning to believe it has.

BE VERY CAREFUL disassembling your FARS plates! With only 6.3 years use, mine crumbled in my hand as I replaced fan...replacement plates ordered from SI.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: CW2274 on July 29, 2018, 10:32:35 PM
Now all i have to do is sit here a wait for them to show up, that is the hard part lol.
Yeah, it's been Christmas for a lot of you guys around here, buying stuff left and right, kinda jealous.... Actually, I'm seriously considering picking up a psycho-dyne, as CW7491 has, and see if the drier air here has lessened the wet bias and/or premature aging, as I'm leaning to believe it has.

BE VERY CAREFUL disassembling your FARS plates! With only 6.3 years use, mine crumbled in my hand as I replaced fan...replacement plates ordered from SI.
I replaced my top two plates and solar PCB cover about this time last year due to this exact issue, except I managed 10 years outta mine. The bottom plates are still like new. Only structural replacement parts I've ever needed for my VP2.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: Old Tele man on July 29, 2018, 10:39:40 PM
Now all i have to do is sit here a wait for them to show up, that is the hard part lol.
Yeah, it's been Christmas for a lot of you guys around here, buying stuff left and right, kinda jealous.... Actually, I'm seriously considering picking up a psycho-dyne, as CW7491 has, and see if the drier air here has lessened the wet bias and/or premature aging, as I'm leaning to believe it has.

BE VERY CAREFUL disassembling your FARS plates! With only 6.3 years use, mine crumbled in my hand as I replaced fan...replacement plates ordered from SI.
I replaced my top two plates and solar PCB cover about this time last year due to this exact issue, except I managed 10 years outta mine. The bottom plates are still like new. Only structural replacement parts I've ever needed for my VP2.
Yep, those are the plates that fell apart as I handled them. So much for being UV-resistant -- NOT!
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: Bobvelle on July 30, 2018, 02:21:47 AM
I made a mistake in an earlier post and corrected it. The sensor I was/am reconditioning is not a SHT-15 it is in an 11.

I guess I wasn't very clear  :? Sorry bout dat
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: ValentineWeather on July 30, 2018, 06:32:09 AM
Have a new shield to test in few weeks. The Metoshield standard will fit the Davis sensor now, no mention if this was with or without filter cover.

If interested in going FARSLESS (I am), I'll be testing these units when I finally get one or two in hand. 
It will be a couple weeks before in stock however in meantime I'll continue testing the Davis 7714.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: jgentry on July 30, 2018, 06:56:14 AM
Have a new shield to test in few weeks. The Metoshield standard will fit the Davis sensor now, no mention if this was with or without filter cover.

If interested in going FARSLESS (I am), I'll be testing these units when I finally get one or two in hand. 
It will be a couple weeks before in stock however in meantime I'll continue testing the Davis 7714.

Keep us posted. Would be interested to see how that shield compares to the FARS & Davis passive shield.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: ValentineWeather on July 30, 2018, 07:07:50 AM
Will do, rest of the week looks better for testing 7714 also. Hoping I have at least 1-2 days of light winds so can get some real numbers.

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Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: jerryg on July 30, 2018, 07:39:22 AM
Just got an email from Jan Barani  that my pro shield will ship out right away as they are in stock in the usa store and the standard will be a little later as they are about to be shipped to the usa store and have to go thru all the processing for imported products.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: ValentineWeather on July 30, 2018, 07:53:09 AM
Just got an email from Jan Barani  that my pro shield will ship out right away as they are in stock in the usa store and the standard will be a little later as they are about to be shipped to the usa store and have to go thru all the processing for imported products.

Your sensor won't fit in the Pro will it?
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: ValentineWeather on July 30, 2018, 08:01:50 AM
Just got an email from Jan Barani  that my pro shield will ship out right away as they are in stock in the usa store and the standard will be a little later as they are about to be shipped to the usa store and have to go thru all the processing for imported products.

Your sensor won't fit in the Pro will it?

PM from Jerry he has custom SHT75 built for the pro shield.
Performance on 75 does look promising also not displaying the high humidity. 
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: ValentineWeather on July 30, 2018, 09:57:26 AM
Big announcement I posted in original thread also.

The Meteoshield Standard Shield will now accept the Davis SHT sensor. Not sure if this is with large Davis filter however.
They are now taking orders and gave a discount code for fellow forum members if interested.
They expect deliveries to start in about a week.

Code: $25DISCOUNT     will work through August 31
Purchase in USA at: https://www.allmeteo.com/meteo-shop/solar-radiation-shield-for-weather-station-lite

I only posted to help forum members who want to get away from FARS. The safe thing is wait for some test to get done by members and not trust Metoshield testing especially since the SHT is bigger sensor than original probe they used. Airflow may be restricted and shield a failure.
I spent enough time with them being it was my original idea and get the same $25 discount. If the product works great if not don't blame me.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: Bobvelle on July 30, 2018, 10:11:56 AM
Big announcement I posted in original thread also.

The Meteoshield Standard Shield will now accept the Davis SHT sensor. Not sure if this is with large Davis filter however.
They are now taking orders and gave a discount code for fellow forum members if interested.
They expect deliveries to start in about a week.

Code: $25DISCOUNT     will work through August 31
Purchase in USA at: https://www.allmeteo.com/meteo-shop/solar-radiation-shield-for-weather-station-lite

And how much are you making off each sale?

  :grin:  Just Kidding

I wish I could use these but even the greatest passive shield on the planet will have issues in areas with stagnate air, Right?. However... I'm keeping an open mind... and I might bite.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: kcidwx on July 30, 2018, 10:46:41 AM
They have already done some tests. Including the VP2 FARS.

https://www.allmeteo.com/radiation-shield-comparisons/ (https://www.allmeteo.com/radiation-shield-comparisons/)
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: Bobvelle on July 30, 2018, 11:15:45 AM
They have already done some tests. Including the VP2 FARS.

https://www.allmeteo.com/radiation-shield-comparisons/ (https://www.allmeteo.com/radiation-shield-comparisons/)

I looked at that. But I wish they would have recorded (or reported) wind conditions. The gallery photos show a lot of wide open spaces and a couple appear to be next to a large body of water (ocean, sea, gulf?)
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: ValentineWeather on July 30, 2018, 12:56:24 PM
They have already done some tests. Including the VP2 FARS.

https://www.allmeteo.com/radiation-shield-comparisons/ (https://www.allmeteo.com/radiation-shield-comparisons/)

Well it's their product, I know how those test can go.   :-P
 
I'll feel better seeing with my own eyes. That test was done without using the SHT also they used one of the skinny sensors so whole new ballgame with sht taking up more room maybe reducing airflow. 

I regret putting the discount code out if shield is a failure and people waste money.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: Old Tele man on July 30, 2018, 02:12:29 PM
They have already done some tests. Including the VP2 FARS.

https://www.allmeteo.com/radiation-shield-comparisons/ (https://www.allmeteo.com/radiation-shield-comparisons/)

Well it's their product, I know how those test can go.   :-P
 
I'll feel better seeing with my own eyes. That test was done without using the SHT also they used one of the skinny sensors so whole new ballgame with sht taking up more room maybe reducing airflow. 

I regret putting the discount code out if shield is a failure and people waste money.
In weather, as in commerce, CAVEAT EMPTOR
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: ValentineWeather on July 30, 2018, 02:23:47 PM
They have already done some tests. Including the VP2 FARS.

https://www.allmeteo.com/radiation-shield-comparisons/ (https://www.allmeteo.com/radiation-shield-comparisons/)

Well it's their product, I know how those test can go.   :-P
 
I'll feel better seeing with my own eyes. That test was done without using the SHT also they used one of the skinny sensors so whole new ballgame with sht taking up more room maybe reducing airflow. 

I regret putting the discount code out if shield is a failure and people waste money.
In weather as in commerce: CAVEAT EMPTOR

I agree. Buyer beware is another.
Sensor size started worrying me. What if sensor causes restriction?
I'm actually liking what I see on the 7714 so far and it's less than 1/2 the price if purchased through Ryan at SI.
Nice sunny days toward end of the week forecast 95.  =D&gt;
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: CW2274 on July 30, 2018, 04:48:42 PM
They have already done some tests. Including the VP2 FARS.

https://www.allmeteo.com/radiation-shield-comparisons/ (https://www.allmeteo.com/radiation-shield-comparisons/)
And like I stated on the previous page, they conveniently left out the wind, or lack thereof. Without wind data, this test is basically meaningless. Any decent passive shield will keep up with a FARS, when there's enough wind. This thing could be the greatest passive shield since sliced bread, but leaving out the most crucial element, the wind, makes me dubious.
Just sayin'....
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: ValentineWeather on July 30, 2018, 09:18:30 PM
Todays test #1 is the passive shield 7714. Looks like +1F difference on high temperature under mainly light wind speeds. Haven't looked it over exactly where solar, wind, temperature were.  Just putting it out for any others who want to evaluate and comment. 

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Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: jerryg on July 30, 2018, 10:22:51 PM
Here's a interesting test comparison of the shield. Scroll down to the pix of stevenson screen and expand the comments. https://www.facebook.com/allmeteo/
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: ValentineWeather on July 30, 2018, 10:51:25 PM
And those are all passive shields. Doesn't say much good about the Vaisala. Big numbers for all being passive just shows how different they can be and why some don't trust passive shields.  Good comparison for the Meteoshield. 
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: ValentineWeather on July 30, 2018, 10:58:23 PM
Jerry would you know if the lite and standard are same shields. Noticed on FB they used the term lite in Aug 2017.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: Old Tele man on July 31, 2018, 12:08:41 AM
Todays test #1 is the passive shield 7714. Looks like +1F difference on high temperature under mainly light wind speeds. Haven't looked it over exactly where solar, wind, temperature were.  Just putting it out for any others who want to evaluate and comment. 

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Looks to me as though DFARS would likely be adequate, of course, you're not at 100F and still winds.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: jgentry on July 31, 2018, 12:29:41 AM
Here is some interesting research on radiation shields...

https://journals.ametsoc.org/doi/pdf/10.1175/1520-0426(2001)018%3C0851%3ATEOTAM%3E2.0.CO%3B2
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: ValentineWeather on July 31, 2018, 06:41:59 AM
Todays test #1 is the passive shield 7714. Looks like +1F difference on high temperature under mainly light wind speeds. Haven't looked it over exactly where solar, wind, temperature were.  Just putting it out for any others who want to evaluate and comment. 



Looks to me as though DFARS would likely be adequate, of course, you're not at 100F and still winds.

Think so too. The meteoshield results will be interesting. I don't think it can do any better, how can it? But who knows without testing. One of the knocks on Davis fars it read lower than reference on calm days and higher windy days. Theoretically based on WMO study the reference may have been dead on with the fars reading low being 7714 was within 97-99% of reference in desert testing with 40-45c common temperatures.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: Bobvelle on July 31, 2018, 12:25:05 PM
Here is some interesting research on radiation shields...

https://journals.ametsoc.org/doi/pdf/10.1175/1520-0426(2001)018%3C0851%3ATEOTAM%3E2.0.CO%3B2

Maybe I don't know what the hell I'm looking at (very likely  :-P) but the graphs seem to show the gill plate shield doing pretty well against the others. At least in the inner shield temp vs the sensor temp.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: ValentineWeather on August 01, 2018, 06:47:36 AM
Oops! forgot the other graphs,

Day-2, was a great test day with light winds and only few clouds later. 7714 was +1.6F vs FARS at the in town station with less air movement .  Not sure if this is acceptable for all but IMO still not a total bust.  Hoping the Meteoshield does better.

The wind speeds are recorded at 30' not ground level.

The station outside of town wide open, temp max was 85, 1 degree lower most likely due to better air movement.
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Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: Bobvelle on August 01, 2018, 10:50:03 AM
So I'm confused. The 7714 passive shield plates come out of the box, black on the underside ? Or you had to paint them?
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: dendrite on August 01, 2018, 11:04:40 AM
I think I'd give up that 4% RH in exchange for the 1.5F temperature, but that's just me. That's definitely not bad for a passive with almost full sun on it all day though. Temp is always my first priority. Humidity is way down the list...probably a hair above solar/uv.  ;)
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: ValentineWeather on August 01, 2018, 12:05:31 PM
So I'm confused. The 7714 passive shield plates come out of the box, black on the underside ? Or you had to paint them?

I painted mine  Flat Black just bottom plate where sensor mounts  and the nearest top plate toward sensor. I used painters blue tape edges around upper plate so only white (no black) was exposed to sun. Instructions on assembly can be tricky. Better to assembly first time then once you figure that out you will understand what parts I painted black.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: hwcorder on August 01, 2018, 01:07:09 PM
For some of you that have extra money lying around and want to go high tech with your black coating. By the way its apparently on sale!  :lol:

https://www.acktar.com/product/light-absorbing-sample-kit-standard-adhesive/
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: Bobvelle on August 01, 2018, 01:11:59 PM
So I'm confused. The 7714 passive shield plates come out of the box, black on the underside ? Or you had to paint them?

I painted mine  Flat Black just bottom plate where sensor mounts  and the nearest top plate toward sensor. I used painters blue tape edges around upper plate so only white (no black) was exposed to sun. Instructions on assembly can be tricky. Better to assembly first time then once you figure that out you will understand what parts I painted black.

Oh OK..So it was the Metoeshield that comes black on the underside. I got them confused.
I just looked at the Meteoshield specs and It's a lot smaller than the Davis shields as far as diameter. Inside diameter is ~ 2.56". But if you could mount the SHTxx PCB vertically (as in the cable hanging straight down) you should have ~.5" on either side which would allow you to place the PCB off-center. thereby positioning the sensor about center. This would allow an upward draft through the center with only the Davis filter cap (assuming you use it) in the airflow.  However, horizontal airflow would be blocked. But according to the design intent, and unlike most gill plate shields.. natural aspiration should be a "quasi-spiral-vertical" (Helical) movement, should it not?
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: ValentineWeather on August 01, 2018, 02:33:58 PM
So I'm confused. The 7714 passive shield plates come out of the box, black on the underside ? Or you had to paint them?

I painted mine  Flat Black just bottom plate where sensor mounts  and the nearest top plate toward sensor. I used painters blue tape edges around upper plate so only white (no black) was exposed to sun. Instructions on assembly can be tricky. Better to assembly first time then once you figure that out you will understand what parts I painted black.

Oh OK..So it was the Metoeshield that comes black on the underside. I got them confused.
I just looked at the Meteoshield specs and It's a lot smaller than the Davis shields as far as diameter. Inside diameter is ~ 2.56". But if you could mount the SHTxx PCB vertically (as in the cable hanging straight down) you should have ~.5" on either side which would allow you to place the PCB off-center. thereby positioning the sensor about center. This would allow an upward draft through the center with only the Davis filter cap (assuming you use it) in the airflow.  However, horizontal airflow would be blocked. But according to the design intent, and unlike most gill plate shields.. natural aspiration should be a "quasi-spiral-vertical" (Helical) movement, should it not?

I was in contact with Jan at Metoshield about the big stock filter, he thought it would work. Until I get the shield and see not totally convinced so ordered some of the small filters just in case.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: jerryg on August 01, 2018, 03:02:21 PM
I was wondering the same thing about the big sensor blocking the spiraling air
 flow or disrupting it so much it might not meet the specs of a smaller round probe designed for it. I would think at the least it might be the thing to do to remove the big davis filter in favor of the smaller low profile of the sf1.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: Bobvelle on August 01, 2018, 03:19:52 PM
So I'm confused. The 7714 passive shield plates come out of the box, black on the underside ? Or you had to paint them?

I painted mine  Flat Black just bottom plate where sensor mounts  and the nearest top plate toward sensor. I used painters blue tape edges around upper plate so only white (no black) was exposed to sun. Instructions on assembly can be tricky. Better to assembly first time then once you figure that out you will understand what parts I painted black.

Oh OK..So it was the Metoeshield that comes black on the underside. I got them confused.
I just looked at the Meteoshield specs and It's a lot smaller than the Davis shields as far as diameter. Inside diameter is ~ 2.56". But if you could mount the SHTxx PCB vertically (as in the cable hanging straight down) you should have ~.5" on either side which would allow you to place the PCB off-center. thereby positioning the sensor about center. This would allow an upward draft through the center with only the Davis filter cap (assuming you use it) in the airflow.  However, horizontal airflow would be blocked. But according to the design intent, and unlike most gill plate shields.. natural aspiration should be a "quasi-spiral-vertical" (Helical) movement, should it not?

I was in contact with Jan at Metoshield about the big stock filter, he thought it would work. Until I get the shield and see not totally convinced so ordered some of the small filters just in case.

Well I think there is room... but then the bigger question is... how and what would you mount it to? There are no mounting brackets up inside the interior that I'm aware of. Looking at the PDFs, the only "bracket" for mounting a sensor is the 1/2" or 3/4" hole in the bottom plate for what looks like a "seal-tite" elec. box connector. Some kind of home-brew bracket/mount would have to be found by sorting through the 30+ years of junk I have stashed here and there. But, after all, isn't that the fun of it.  :-P
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: ValentineWeather on August 01, 2018, 03:35:37 PM
I was wondering the same thing about the big sensor blocking the spiraling air
 flow or disrupting it so much it might not meet the specs of a smaller round probe designed for it. I would think at the least it might be the thing to do to remove the big davis filter in favor of the smaller low profile of the sf1.


I thought the 31's took the SF2's You sent me a link. That's what I ordered. So do I have the wrong filter coming?

Sensirion says its the SF2.   #-o SF2 Filter Cap
For SHT2x and SHT3x Humidity Sensors


https://www.sensirion.com/en/environmental-sensors/humidity-sensors/filter-cap-sf2/
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: dendrite on August 01, 2018, 03:42:52 PM
I was wondering the same thing about the big sensor blocking the spiraling air
 flow or disrupting it so much it might not meet the specs of a smaller round probe designed for it. I would think at the least it might be the thing to do to remove the big davis filter in favor of the smaller low profile of the sf1.


I thought the 31's took the SF2's You sent me a link. That's what I ordered. So do I have the wrong filter coming?

Sensirion says its the SF2.   #-o SF2 Filter Cap
For SHT2x and SHT3x Humidity Sensors


https://www.sensirion.com/en/environmental-sensors/humidity-sensors/filter-cap-sf2/
I think youre fine. I believe the SF1 was for the SHT1x.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: openvista on August 01, 2018, 03:48:51 PM
Here is some interesting research on radiation shields...

https://journals.ametsoc.org/doi/pdf/10.1175/1520-0426(2001)018%3C0851%3ATEOTAM%3E2.0.CO%3B2

Summary:

ASOS > CRS > MMTS > Gill = rank of solar radiation shield effectiveness.
CRS > MMTS > Gill > ASOS = DAYTIME rank of infrared radiation shielding effectiveness.
Gill ≥ MMTS > CRS ≈ ASOS = NITETIME rank of infrared radiation shielding effectiveness.

...where:

ASOS = Automated Surface Observing System shield
MMTS = Maximum-Minimum Temperature System shield
CRS = Cotton Region (Stevenson) Shelter.
Gill = multliple-plate cylindrical shaped shield

That's the old ASOS shield (circa 2000) that had the chilled mirror in it. They had to leave the bottom open which really messed it up with ground reflected radiation, especially at night. They discuss this in the abstract and then again around pp 861-863 in the paper.

The newer ASOS's have a separate housing for dew point. Not sure, but I doubt, the aspirated temperature shield is still left open at the bottom now. Ron would have to verify.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: ValentineWeather on August 01, 2018, 03:57:39 PM
I was wondering the same thing about the big sensor blocking the spiraling air
 flow or disrupting it so much it might not meet the specs of a smaller round probe designed for it. I would think at the least it might be the thing to do to remove the big davis filter in favor of the smaller low profile of the sf1.


I thought the 31's took the SF2's You sent me a link. That's what I ordered. So do I have the wrong filter coming?

Sensirion says its the SF2.   #-o SF2 Filter Cap
For SHT2x and SHT3x Humidity Sensors


https://www.sensirion.com/en/environmental-sensors/humidity-sensors/filter-cap-sf2/
I think youre fine. I believe the SF1 was for the SHT1x.

Could be the SF1 has to be larger, maybe that's what he likes it for better handling and gluing down. Can't image any sensor smaller than the tiny 31's so about any filter should fit.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: CW7491 on August 01, 2018, 04:54:59 PM
Here is some interesting research on radiation shields...

https://journals.ametsoc.org/doi/pdf/10.1175/1520-0426(2001)018%3C0851%3ATEOTAM%3E2.0.CO%3B2

Summary:

ASOS > CRS > MMTS > Gill = rank of solar radiation shield effectiveness.
CRS > MMTS > Gill > ASOS = DAYTIME rank of infrared radiation shielding effectiveness.
Gill ≥ MMTS > CRS ≈ ASOS = NITETIME rank of infrared radiation shielding effectiveness.

...where:

ASOS = Automated Surface Observing System shield
MMTS = Maximum-Minimum Temperature System shield
CRS = Cotton Region (Stevenson) Shelter.
Gill = multliple-plate cylindrical shaped shield

That's the old ASOS shield (circa 2000) that had the chilled mirror in it. They had to leave the bottom open which really messed it up with ground reflected radiation, especially at night. They discuss this in the abstract and then again around pp 861-863 in the paper.

The newer ASOS's have a separate housing for dew point. Not sure, but I doubt, the aspirated temperature shield is still left open at the bottom now. Ron would have to verify.

I was surprised when I saw for myself the ASOS HO-1088 is still open at the bottom with the temperature sensor nearly all the way at the bottom. The only thing between the sensor and the ground is a screen. And Im not certain, but I dont even think theyve removed the chilled mirror device; they just dont use it. 
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: Bobvelle on August 01, 2018, 05:05:46 PM
I was wondering the same thing about the big sensor blocking the spiraling air
 flow or disrupting it so much it might not meet the specs of a smaller round probe designed for it. I would think at the least it might be the thing to do to remove the big davis filter in favor of the smaller low profile of the sf1.


I thought the 31's took the SF2's You sent me a link. That's what I ordered. So do I have the wrong filter coming?

Sensirion says its the SF2.   #-o SF2 Filter Cap
For SHT2x and SHT3x Humidity Sensors


https://www.sensirion.com/en/environmental-sensors/humidity-sensors/filter-cap-sf2/
I think youre fine. I believe the SF1 was for the SHT1x.

Could be the SF1 has to be larger, maybe that's what he likes it for better handling and gluing down. Can't image any sensor smaller than the tiny 31's so about any filter should fit.

SF2 is for the SHT3x
SF1 is for the SHT1x

SF2 is just an open box underneath that covers the whole sensor. It leaves a airspace all the way around the sensor.
SF1 has a tunnel like opening that is offset to only allow the actual sensor orifice of the SHT11 or 15 exposed to the membrane. It's designed specifically for the SH1x series sensor and AFAIK will not fit any other sensor.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: ValentineWeather on August 01, 2018, 05:24:04 PM
Thanks so have the right one coming.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: ValentineWeather on August 01, 2018, 11:05:07 PM
Day 3, summary passive shield 7714 (+1.2F) over FARS on high temperature. Mostly sunny just few clouds temperatures 70's, winds up just a little (1-9 mph) with passing of weak cold front. Wind measured at 30'.
Expect mid 90's tomorrow will be warmest test day.
Acceptable.
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Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: ValentineWeather on August 02, 2018, 09:50:35 PM
Only .3F difference day 4 mid 90's with wind passive and fars are the same.
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Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: CW2274 on August 02, 2018, 10:17:51 PM
With that wind, should be close. When conditions are ripe, show us, as we used to say, a "dac" day. ;)
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: ValentineWeather on August 02, 2018, 10:33:57 PM
The 7714 is best passive shield I've tested so far.
But the shield I'm really looking forward to is the meteoshield.  This was my baby giving Jan the idea of fitting Davis sensor inside so really hope it performs.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: jerryg on August 03, 2018, 01:46:28 PM
Ok this is just a quick update got the two shields in awhile ago and just put out the pro, wanted to try it at noon in the heat of the day and little to no wind right now and the fars is showing 90.6 and the pro 90.1 first quick look and the standard shield has plenty of room for the davis sensor it can be wiggled around inside. Will give up date later when get some good looks at the pro.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: jerryg on August 03, 2018, 03:06:11 PM
Just had a thought if i remember right i think that a passive shield is supposed to run cooler at night than a fars. It will be another thing i check out tonight to see how much if any temp difference there is.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: jgentry on August 03, 2018, 03:59:28 PM
Just had a thought if i remember right i think that a passive shield is supposed to run cooler at night than a fars. It will be another thing i check out tonight to see how much if any temp difference there is.


How is the FARS and the Barani shield comparing now?
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: ValentineWeather on August 03, 2018, 04:10:13 PM
Barani shields are still in customs, takes about a week maybe getting close now. Once retailer receives they get shipped to customers.

Jerry I don't find high noon the time of day for passive shields showing most error, this usually starts around 4pm and ends around 6:30 pm this time of year.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: jerryg on August 03, 2018, 04:24:03 PM
Maybe so i am sitting here looking at the two stations and i can not figure out why the fars is running on average a degree higher. I was concerned about temp spike of the pro and now i wonder about the fars. I moved the shield between the two fars and nothing changed and i moved the sensor inside the fars between the two fars and same thing. The difference is always the same no matter the combo. One thing the mounting for the Barani shield is sort of universal mounts with screws  or u bolts the ones from Davis mount fit fine. Tomorrow i am going to get the standard shield set up with a 31 sensor.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: dendrite on August 03, 2018, 05:06:14 PM
So which sensors are in which shields? Pretty crazy the FARS is running warmer. What are you using for a fan in the FARS? I have 40 CFM going through so way more than the Davis stock.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: jerryg on August 03, 2018, 05:31:46 PM
I have an sht 75 in my main station and i just set out the standard shield with a Davis sht 31 and my fars is also an sht 31. All the sensors were compared in temp to each other and were always within a .1 to .2 of each other. I made a mount for the standard shield that works pretty well, nothing fancy but the unit comes with a cable clamp fitting that i put a 6 inch piece of tubing into that is 1 inch outside diameter and just fits and lets me slide it up and down to position the sensor in a good spot and then tighten it down to secure it. The two Barani shields are running pretty close to each other in temp. That's a good sign for Davis sensor users. Will know more after watching it for awhile, really waiting for tonight to see how the humidity pans out.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: ValentineWeather on August 03, 2018, 06:05:38 PM
Okay after reading all the threads looks like this will turn into a Barani shield test thread also. I'll add the name to title.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new Barani shield
Post by: ValentineWeather on August 03, 2018, 06:12:22 PM
Yes good sign if Fars is running higher unless Jerry has modified Davis shield causing it to run warmer, like I did with open bottom (Don't do this),  :oops:
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new Barani shield
Post by: jerryg on August 03, 2018, 07:31:10 PM
No mods just Davis fars with stock fans.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: Bobvelle on August 04, 2018, 02:59:48 AM
Barani shields are still in customs, takes about a week maybe getting close now. Once retailer receives they get shipped to customers.

OK... Barani...Meteoshield...Standard shield  ](*,) Are we all talking about the same thing here?

And If so, Doesn't Jerryg and Jgentry already have the Meteoshields? How are they held up in Customs...???
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new Barani shield
Post by: ValentineWeather on August 04, 2018, 03:13:10 AM
Jerry I know you like using the 75 for humidity but for testing purposes I would stick to the 31's reason being I believe when the 31's came out they ran .3-.5F warmer than the SHT15's and 11's in certain ranges. They were not off just highly accurate and don't know where the 75 is on this accuracy scale because specs are more in line with the 15's.
 
One of the impressive things with the SHT31's they all matched with temperature within .1 and still do new and old sensors as long as proper offset according to transmitter manufacturer date (pre -.9 ) Jan 2016 is used.
 
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: ValentineWeather on August 04, 2018, 03:35:15 AM
Barani shields are still in customs, takes about a week maybe getting close now. Once retailer receives they get shipped to customers.

OK... Barani...Meteoshield...Standard shield  ](*,) Are we all talking about the same thing here?

And If so, Doesn't Jerryg and Jgentry already have the Meteoshields? How are they held up in Customs...???

Actual name of shield is METEOSHIELD made by BARANI DESIGN brand of meteorological sensors.  Two versions STANDARD version was designed to hold the Davis size sensor.  PRO sensor chamber isn't as wide with black interior and longer for some of the high dollar sensors to fit.

allMETEO is the distributor.

All I know is Jerry got his yesterday and when I first posted was told by distributor allMETEO in email they would be in customs for about a week and as soon as cleared and received would ship orders out.
 
I think Jerry got a set of shields which had already cleared customs prior because first big order went to USGA which cleaned original stock out so this is another batch being received by distributor.

Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: Bobvelle on August 04, 2018, 03:59:11 AM
Barani shields are still in customs, takes about a week maybe getting close now. Once retailer receives they get shipped to customers.

OK... Barani...Meteoshield...Standard shield  ](*,) Are we all talking about the same thing here?

And If so, Doesn't Jerryg and Jgentry already have the Meteoshields? How are they held up in Customs...???

Actual name of shield is METEOSHIELD made by BARANI DESIGN brand of meteorological sensors.  Two versions STANDARD version was designed to hold the Davis size sensor.  PRO sensor chamber isn't as wide with black interior and longer for some of the high dollar sensors to fit.

allMETEO is the distributor.

All I know is Jerry got his yesterday and when I first posted was told by distributor allMETEO in email they would be in customs for about a week and as soon as they cleared and they received would ship orders out.
 
I think Jerry got a set of shields which had already cleared customs prior because first big order went to USGA which cleaned original stock out so this is another batch being received by distributor.

Sorry, My statement about the different names was a failed attempt at sarcasm. I assumed we were using 3 different names for the same thing. I think calling it a "standard shield" is likely to cause confusion to readers though.

Understood about the Customs issue. I thought none of the new Meteoshields had made it to any distributors yet. Then members say they set one up?? It was confusing.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 04, 2018, 05:23:55 AM
Here are the shield differences; 
   PRO
ULTIMATE PRECISION
Double louver design eliminates heat transfer
Light absorbent black inner louvers
UV & impact resistant Titanium white outside
Hydrophobic plastic.
Maintenance free; not affected by soiling and dirt.
No flat surfaces = spider web free on the inside.                                                 

Standard
SUPERB ACCURACY & PROTECTION
Slotted louver design reduces heat transfer
Large inner volume (Diam: 65mm, Height: 150mm) Fits Davis SHT31
UV & impact resistant Titanium white outside
Hydrophobic plastic.
MeteoShield does not like bugs and bugs don't like it either.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: dendrite on August 04, 2018, 06:00:56 AM
The Pro version should work for those of us with SHT75 setups.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: jerryg on August 04, 2018, 07:37:35 AM
I am going to be doing some swapping around with sensors, right now i am running 75's in both Barani shields to compare the two shields. I had the 75's together and checked the temp of each side by side so i know they match pretty well. At the same time i have a 31 in the fars which matched in temp with the 75's. After todays run i am going to put the 31 in the standard shield and move the 75 to the fars and compare that way. Right now the pro and standard temps are the same as well as the fars all at 74.0f degrees.
Title: Re: WMO field study thermometer shield FARS 7755, Passive 7714
Post by: dport on August 04, 2018, 08:17:04 AM
Barani shields are still in customs, takes about a week maybe getting close now. Once retailer receives they get shipped to customers.

OK... Barani...Meteoshield...Standard shield  ](*,) Are we all talking about the same thing here?

And If so, Doesn't Jerryg and Jgentry already have the Meteoshields? How are they held up in Customs...???

Actual name of shield is METEOSHIELD made by BARANI DESIGN brand of meteorological sensors.  Two versions STANDARD version was designed to hold the Davis size sensor.  PRO sensor chamber isn't as wide with black interior and longer for some of the high dollar sensors to fit.

allMETEO is the distributor.

All I know is Jerry got his yesterday and when I first posted was told by distributor allMETEO in email they would be in customs for about a week and as soon as cleared and received would ship orders out.
 
I think Jerry got a set of shields which had already cleared customs prior because first big order went to USGA which cleaned original stock out so this is another batch being received by distributor.

The USGA is buying up these bad boys?  Interesting.  I wonder what they have been using prior to the new shield.  If it was some kind of FARS, this will be a huge reduction in work for the folks trying to maintain the stations. 
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: jgentry on August 04, 2018, 10:35:11 AM
Hey Jerry, how did your lows and maximum humidity compare between the FARS & Barani shield?
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: jerryg on August 04, 2018, 10:56:14 AM
Ok just a little change up to stuff, i now have my new 31 in the standard shield in its permanent spot and the fars is still the 31 and the pro is still the 75. Now i can do some good checks between them.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: jgentry on August 04, 2018, 11:04:11 AM
My interest in the Barani shield has gone up. Jerry, Could you post some pics on here on how you mounted the Barani pro shield?  Also, how is the response time compares to the FARS?
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: DaleReid on August 04, 2018, 11:26:49 AM
Jerry, do you have an RM Young or Vaisala radiation shield to put head to head against the Baranti? 

They have been around a long time, are 'standard' but very pricey new (eBay has them pretty good once in awhile) and I'm wondering if the new design as taken the passive method one step further towards true ambient temps.

I recall seeing a graph from Young, I think, on how wind speed affects the temperature, based against temperature.  It was as much as 4 degrees different on a calm warm day, if I recall.

Are you also logging if there is sunshine vs. overcast to see if there are greater degrees of disparity on a cloudy day vs. sunshine?
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: DaleReid on August 04, 2018, 11:28:05 AM
Every time I read 'Baranti' I think I should be over on the Coffee Geeks site reading about the newest espresso machine or coffee grinder. 
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: jerryg on August 04, 2018, 12:20:54 PM
Well as far as pictures go don't know how to post on here, might figure it out. Its not too fancy just mounted on my tower with an 8 feet galvanized pipe mounted cross ways on it with virtical mounting pipes. The standard shield is on one end and the pro is on the other connected to the iss mounted on the standard Davis mount with the uv and solar sensors so have a longer cable made up on my 75 sensor i made so i could mount the shield facing north so as not to shade the sensors. The standard was easier even though it had the shorter cable from the 31 sensor. I used the metal Davis mounting plate that fits the fars setup and i mounted the iss using one of the holes nearest the shield, i do not use Davis rain gauges all mine are external gauges so i don't have the problem of keeping it level and bulky. This mount is my test mount and i don't use it for anything else so didn't need rain gauge or anything else to mount on the plate. If i had the rain gauge set up then i would have had to extend the cable or figure out some really fancy way moving the iss to get it better located but then rain gauge wouldn't reach  ](*,)
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 04, 2018, 12:24:19 PM
Jerry, do you have an RM Young or Vaisala radiation shield to put head to head against the Baranti? 

They have been around a long time, are 'standard' but very pricey new (eBay has them pretty good once in awhile) and I'm wondering if the new design as taken the passive method one step further towards true ambient temps.

I recall seeing a graph from Young, I think, on how wind speed affects the temperature, based against temperature.  It was as much as 4 degrees different on a calm warm day, if I recall.

Are you also logging if there is sunshine vs. overcast to see if there are greater degrees of disparity on a cloudy day vs. sunshine?

If anything the Davis fars over cooled on calm days. How's that possible you might ask, it may have something to do with Venturi effect  through sensor chamber shedding heat prior to sensor, ( like heat exchanger does but with air) for whatever reason they scored it lower because of it. 
So IMO the Davis FARS as reference may be bad choice because it reads low on calm days, but for Davis owners is all that matters, how does it compare.
Read the comments of WMO study. I found it odd a shield could actually over cool but the Davis FARS does. 

If meteoshield beats the Davis passive 7714 that will be impressive. The calm days my test the 7714 was 1.6 higher than Davis Fars which may be actually overcooling. The 7714 was with reference shield 97-99% of time depending on wind speeds and scored a perfect 5 of 5 rating.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: jerryg on August 04, 2018, 12:27:58 PM
Since i got the sensors where i want them i have been keeping a written log every half hour, while i sit here watching movies lol, and note the sky conditions when i take the reading along with air speed.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: jgentry on August 04, 2018, 01:23:04 PM

If anything the Davis fars over cooled on calm days. How's that possible you might ask, it may have something to do with Venturi effect  through sensor chamber shedding heat prior to sensor, ( like heat exchanger does but with air) for whatever reason they scored it lower because of it. 
So IMO the Davis FARS as reference may be bad choice because it reads low on calm days, but for Davis owners is all that matters, how does it compare.
Read the comments of WMO study. I found it odd a shield could actually over cool but the Davis FARS does. 


If meteoshield beats the Davis passive 7714 that will be impressive. The calm days my test the 7714 was 1.6 higher than Davis Fars which may be actually overcooling. The 7714 was with reference shield 97-99% of time depending on wind speeds and scored a perfect 5 of 5 rating.
[/quote]

From allmeto.com

BASED IN INDEPENDENT TESTING FROM CUSTOMERS IN REAL WORLD APPLICATIONS (LITTOCLIME, FRANCE 2017)
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: openvista on August 04, 2018, 01:35:42 PM
It makes perfect sense to me that the FARS would be cooler than the passive reference shield on low wind days. The study authors even admit that the reference shield exhibited solar errors on such days.

Also, the FARS is pretty impervious to wind, which either has to enter above the sensor and go through the fan that's blowing perpendicular to the air flow or enter from the bottom to get sucked into the chamber. We know the Davis stock fan is not that powerful. So it's not hard to imagine the chamber temp being just a bit warmer than passive shields if the wind is strong enough.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: jgentry on August 04, 2018, 01:37:39 PM
Well as far as pictures go don't know how to post on here, might figure it out. Its not too fancy just mounted on my tower with an 8 feet galvanized pipe mounted cross ways on it with virtical mounting pipes. The standard shield is on one end and the pro is on the other connected to the iss mounted on the standard Davis mount with the uv and solar sensors so have a longer cable made up on my 75 sensor i made so i could mount the shield facing north so as not to shade the sensors. The standard was easier even though it had the shorter cable from the 31 sensor. I used the metal Davis mounting plate that fits the fars setup and i mounted the iss using one of the holes nearest the shield, i do not use Davis rain gauges all mine are external gauges so i don't have the problem of keeping it level and bulky. This mount is my test mount and i don't use it for anything else so didn't need rain gauge or anything else to mount on the plate. If i had the rain gauge set up then i would have had to extend the cable or figure out some really fancy way moving the iss to get it better located but then rain gauge wouldn't reach  ](*,)

You should see attachments below the written section. So basically I can take a mounting bracket for the Davis temp/hum station and install the Barani pro shield underneath it like the Davis stock shield?
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: jerryg on August 04, 2018, 01:52:25 PM
Not quite sure what you are saying, but if you want to replace the davis shield with the barani  you could i guess but it would take a lot of thinking out how to make it fit to the base of the davis setup. If you needed it underneath the davis set up then the best way would be to mount the barani on the support at the proper height and then mount the davis base on top of it using the separate mounting brackets. I would not try mounting it to the base of the davis because you would have to make some kind of bracket to top mount the barani, i noticed in their ads they say top mount is available. Might be able to use the top set up to do it.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 04, 2018, 01:58:32 PM
One thing to remember, you can't get far away from ISS because plugs on these 31's are shorter than ever now. Barely reaches as is and gives no wiggle room.

 I don't know what Davis was thinking maybe trying to sell the 30' plugs. Oh yeah we could always purchase the 30 footers for extra $10.

Also for mounting on pipe you could leave existing shield base and just mount under like I did on the 7714.

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Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: jerryg on August 04, 2018, 02:25:54 PM
Pictures standard and pro
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: jerryg on August 04, 2018, 03:16:38 PM
Just some info with the pro generally showing lower temps i took my calibrated temp meter and inserted the probe inside the pro shield and watch console and meter they were dead on with each other so the readings are correct. My meter certified +/- .3f pretty close to dead on when checked with factory calibrator box. It looks like the pro is pretty niffty. The standard shield so far has stayed even with the fars and at times slightly lower in temp, looks good also.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 04, 2018, 03:34:39 PM
Look good Jerry
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 04, 2018, 03:36:59 PM
If you can get images to computer say email, I've alway found the snipping tool to be handy for easy publish.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: jerryg on August 04, 2018, 03:37:47 PM
Short update averages from 10 am to 2:30 pm  pro 83.9  standard 84.4 fars 84.5
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: jgentry on August 04, 2018, 04:37:42 PM
Pictures standard and pro

Those pics are a great help!  Thanks!  I can mount the Barani mount on my pvc pipe. Planning on using a SHT-75 in the shield.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 04, 2018, 05:13:56 PM
Short update averages from 10 am to 2:30 pm  pro 83.9  standard 84.4 fars 84.5

What sensors in pro again?
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: jerryg on August 04, 2018, 05:25:48 PM
sht 75
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: jgentry on August 04, 2018, 05:30:28 PM
sht 75

Are you using the pro shield for your main station that you have uploading data online?
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: jgentry on August 04, 2018, 06:04:27 PM
BTW: This is my current setup. Planning on mounting the Barani shield mount on the pvc.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 04, 2018, 06:16:27 PM

Final update today great test day, it couldn't get better with no wind at peak heat of afternoon. High was 1.5 difference with zero wind speeds. Not bad. 88 FARS 89.5 on 7714 shield. Passing grade B-,  I'll wait for the meteoshild now unless I see something unusual.

Just entered the witching hour 5pm for passive shields with zero wind at 30'.  +1.5 differential on the 7714.
Sure wish I had a Metoshield this doesn't happen often with no wind during heat of day.  Shows solar radiation error is
better than many passive shields but still some room for improvement.

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Adjust solar level bubble it was off.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: jerryg on August 04, 2018, 06:17:08 PM
Yes the pro shield is on my main uploading site and if it keeps working the way it has been it will stay that way from now on. \:D/
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: jgentry on August 04, 2018, 07:46:47 PM
Yes the pro shield is on my main uploading site and if it keeps working the way it has been it will stay that way from now on. \:D/

I know its not easy to tell since the temp updates every 10-12 secs and the humidity updates every 60 seconds; but can you tell me if the response time from Barani Shields is the same as the FARS?
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 04, 2018, 07:51:15 PM
Jerry did you plug the holes? I would think shield wasn't designed to have air flow coming in bottom middle.  Just a thought may change original design.
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Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: jerryg on August 04, 2018, 07:59:04 PM
No i don't think it's necessary or they would have made the adapter set up air tight because the shield at the top of the adapter is wide open so same-o same-o.  Here are my final averages for the day. pro 86.7 standard 87.3 and fars 87.3 how about that match, uncanny how it worked out.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: jerryg on August 04, 2018, 08:02:18 PM
Forgot to answer other question, it is more of an educated guess but with the good air flow on the barani shield i really never noticed any real lag time between the two.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: CW2274 on August 04, 2018, 08:23:09 PM
Just saw this from Barani's web site:

Removes influences of city walls on temperature
Not affected by radiating heat from city walls, pavement, and sun reflections, real-air-temperature measurements are a reality with the MeteoShield. Urban climate research with WMO accuracy in a dense urban environment is now possible.
Learn to trust your data.


Really?? Someone please explain to me how this shield is so smart it knows where the heat's coming from and how to ignore it?

Like I said before, this shield could be the best thing since sliced bread, but some of their statements are preposterous.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: jgentry on August 04, 2018, 08:29:00 PM
Forgot to answer other question, it is more of an educated guess but with the good air flow on the barani shield i really never noticed any real lag time between the two.

Sounds good. It would be interesting to see under calm wind conditions. How are the morning lows and peak humidities conpare?
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 04, 2018, 08:39:22 PM
This is what happened when wind dropped from 3-7 mph down to less than 2 mph and even 0 for extended times today with the Davis passive 7714. So only a calm period will show what the shield can do.  I don't doubt shield is good but finding ideal conditions is rare.
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Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 05, 2018, 06:37:41 AM
No i don't think it's necessary or they would have made the adapter set up air tight because the shield at the top of the adapter is wide open so same-o same-o.  Here are my final averages for the day. pro 86.7 standard 87.3 and fars 87.3 how about that match, uncanny how it worked out.

Thanks....Here is cut out , so this area looks open.
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Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 05, 2018, 06:51:23 AM
Mesowest graphs for Jerrys Meteoshield test yesterday. Wind speeds were high.
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https://mesowest.utah.edu/cgi-bin/droman/meso_base_dyn.cgi?stn=AT358&unit=0&time=LOCAL&product=&year1=&month1=&day1=00&hour1=00&hours=24&graph=1&past=0&order=1

Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: openvista on August 05, 2018, 10:36:05 AM
Just saw this from Barani's web site:

Removes influences of city walls on temperature
Not affected by radiating heat from city walls, pavement, and sun reflections, real-air-temperature measurements are a reality with the MeteoShield. Urban climate research with WMO accuracy in a dense urban environment is now possible.
Learn to trust your data.


Really?? Someone please explain to me how this shield is so smart it knows where the heat's coming from and how to ignore it?

Like I said before, this shield could be the best thing since sliced bread, but some of their statements are preposterous.

Yes, I wondered the same thing. Maybe they mean only the reflected radiation itself (still questionable), but the claim ignores that walls/pavement also conduct heat into the air once they absorb sunshine. That warmed air is certainly not going to be rejected by the shield. That's part of the urban heat island effect. In our small, northerly town that phenomenon is good for at least 1-2F of warming on a sunny, summer day compared to outlying communities at the same elevation.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: hwcorder on August 05, 2018, 10:46:41 AM
Just saw this from Barani's web site:

Removes influences of city walls on temperature
Not affected by radiating heat from city walls, pavement, and sun reflections, real-air-temperature measurements are a reality with the MeteoShield. Urban climate research with WMO accuracy in a dense urban environment is now possible.
Learn to trust your data.


Really?? Someone please explain to me how this shield is so smart it knows where the heat's coming from and how to ignore it?

Like I said before, this shield could be the best thing since sliced bread, but some of their statements are preposterous.

Yes, I wondered the same thing. Maybe they mean only the reflected radiation itself (still questionable), but the claim ignores that walls/pavement also conduct heat into the air once they absorb sunshine. That warmed air is certainly not going to be rejected by the shield. That's part of the urban heat island effect. In our small, northerly town that phenomenon is good for at least 1-2F of warming on a sunny, summer day compared to outlying communities at the same elevation.

Its basically a poorly phrased way of saying the shield will minimize the effects of long wave radiative transfer from surrounding concrete buildings, asphalt, into the sensor.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: jerryg on August 05, 2018, 06:24:53 PM
Going to do max/min temp on the stations. Pro 91.3/73.8  standard 91.3/73.9 fars 91.7/73.7
I need to add the sky conditions to make it more usable. It was mostly cloudy most of the day until late in the afternoon so not much sun to heat things up.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: CW2274 on August 05, 2018, 06:46:02 PM
Going to do max/min temp on the stations. Pro 91.3/73.8  standard 91.3/73.9 fars 91.7/73.7
Not saying it's right or wrong, but certainly one reason the FARS is reading higher is for the simply fact it's drawing air across the sensor allowing for more "direct/instant" reading of the temp whereas the passive is missing it.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 05, 2018, 06:58:48 PM
Going to do max/min temp on the stations. Pro 91.3/73.8  standard 91.3/73.9 fars 91.7/73.7

Bet you can't wait for a sunny still day and see how these shields perform. I know I can't. 
Today's wind speeds looked like:
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Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 06, 2018, 05:13:34 AM
Got email from Jan, was under impression they were here says.

The MeteoShield Std will arrive in the USA any day now. As soon as they are processed, the MeteoShield Pro and Std will ship your way. :-)

 =D&gt;
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: jerryg on August 06, 2018, 07:27:30 AM
Well one of the things about the shield is it is supposed to have good airflow even in low wind conditions giving it it's accuracy. So if that is true then the readings should be close.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 06, 2018, 07:41:47 AM
Jerry was looking at forecast for your area doesn't look like you have any sunny calm wind days coming up.
Looking forward to full sun less than 5 mph at 30' for good test on passive shields.
Can't wait to get my shields hopefully by end of week, I've missed some really good test days already.
 
You probably know this, staggering your uploads to CWOP 15 minutes they may miss low and high temperatures like yesterday CWOP reported high of 90 but you reported 91.   
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: jerryg on August 06, 2018, 08:40:30 AM
Yeah i thought about the upload time i might lower it to 5 minutes for test but i am looking at real time here so did not cross my mine. I know, a real bummer, i had 5 days of clear blue skies with light to calm morning winds and seabreeze winds in the afternoon, perfect for testing and no shields  :-( I got just one day and that was afternoon time just before seabreeze hit. I thought i might get a shot this am but clouds and rain already moving in and morning sun is being block by heavy clouds in the east. I would like to get just one good full day of light wind and sun to test things but the weather gods are laughing at me lol.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: jerryg on August 06, 2018, 08:54:21 AM
Valentine if you want to see the sky conditions click on the banner at the bottom of my post and then click on live web cam at the bottom of the still cam pix and you can see the sky conditions. I changed the upload time to 5 minutes.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 06, 2018, 11:04:37 AM
Yeah i thought about the upload time i might lower it to 5 minutes for test but i am looking at real time here so did not cross my mine. I know, a real bummer, i had 5 days of clear blue skies with light to calm morning winds and seabreeze winds in the afternoon, perfect for testing and no shields  :-( I got just one day and that was afternoon time just before seabreeze hit. I thought i might get a shot this am but clouds and rain already moving in and morning sun is being block by heavy clouds in the east. I would like to get just one good full day of light wind and sun to test things but the weather gods are laughing at me lol.

Good idea at least for length of test we can use the mesowest graph for at least the primary shield.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: jerryg on August 06, 2018, 04:07:30 PM
It's early in the test but i have been watching the temps and we finally go sun with calm to low winds for awhile and with calm wind the standard shield was up to 1 degree warmer than the fars and the pro was even with it but as soon as we got a little wind the temps when down on both, the pro down .5 and the standard down about the same. I decided to compare the two shields to each other and generally the pro runs about 1 degree lower than the standard. It looks like the extra black louvers inside the pro is the big difference. Keeping in mind the possible variations between the sensors as long as there is some wind the standard does a good job against the fars and for the price isn't bad. For those that want the most accurate it looks like the pro is the way to go. Right now wind 4 mph pro is .4 lower and standard is .4 higher. The thing is with the fars my dp always seemed to run high and now it is doing fine. Oh yes, i plugged the hole in the tube, the cable was flopping around in the wind so used some foam rubber and plugged it. Now cable is more secure.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 06, 2018, 04:35:29 PM
In my testing the 31's run about .5F degree warmer than the 15's.
Both the 31 and 15 are in fars only few feet away from each other and this is consistent with the 15 it just runs lower at mid range temps and has similar specs with the 75.

Jerry anything keeping standard shield owners from doing their own flat black interior? Does it split open for access?

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Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: dendrite on August 06, 2018, 04:55:17 PM
A man with a thermometer knows what the temperature is. A man with two thermometers is never sure.  :idea:
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: jerryg on August 06, 2018, 04:58:37 PM
The pro looks like it is put together like the davis plates, stacked with long screws holding them together. The pro is like the standard but with a smaller black louvered shield inside it.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 06, 2018, 05:42:43 PM
The pro looks like it is put together like the davis plates, stacked with long screws holding them together. The pro is like the standard but with a smaller black louvered shield inside it.

I see, so that's the double shield.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: jerryg on August 06, 2018, 05:46:29 PM
Yes that is why the sensor chamber is smaller than the standard, i did not look to much into how the inner shield went into it but i think i would be real careful if i took it apart might be a nightmare to put back together. It looks like you would have to alternate a white then black plate somehow. Should never have to take it apart though if the self cleaning holds up.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: Old Tele man on August 06, 2018, 05:58:23 PM
This link shows a bottom view:

http://www.littoclime.net/abri-meteorologique-cylindrique-a-ventilation-naturelle-shield-standard,fr,4,SHIELD-STD.cfm (http://www.littoclime.net/abri-meteorologique-cylindrique-a-ventilation-naturelle-shield-standard,fr,4,SHIELD-STD.cfm)
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 06, 2018, 06:49:33 PM
Looks like it could be done. Thanks for bottom few on standard.

I ran across this info, the pro shield compared to highly regarded FARS unit. Max error was .5c or (.9f).
The 7714 max error against FARS (DAVIS) has been .9C (1.6f). 
If the standard is much worse than the pro I expect the standard to be about the same as the 7714.
That's why we test.
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Bottom of standard
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Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 07, 2018, 05:06:04 AM
I think it's important inside of these shields be non reflective flat black. Why they didn't' do it on standard shield? Maybe selling point for the more expensive pro model.
Vaisala does their new shields this way, it's almost become a standard now for absorbing accumulated heat thus eliminating the  possible warming inside the shield.

I was testing black spray paints yesterday and figured out you can accelerate the drying time substantially reducing odor by using a hair dryer. I'm going to look at hardware stores today for some Krylon Fusion black silk. This paint claims to work well on plastic and 10 minute dry times. I currently have the Valspar includes primer for plastics which is good quality paint but odor sticks around a day or so.

https://my.vaisala.net/Vaisala%20Documents/Vaisala%20News%20Articles/VN160/VN160_New_Radiation_Shield_Models_DTR502B_and_DTR503A.pdf
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: openvista on August 07, 2018, 07:59:25 AM
I think it's important inside of these shields be non reflective flat black. Why they didn't' do it on standard shield? Maybe selling point for the more expensive pro model.
Vaisala does their new shields this way, it's almost become a standard now for absorbing accumulated heat thus eliminating the  possible warming inside the shield.

I was testing black spray paints yesterday and figured out you can accelerate the drying time substantially reducing odor by using a hair dryer. I'm going to look at hardware stores today for some Krylon Fusion black silk. This paint claims to work well on plastic and 10 minute dry times. I currently have the Valspar includes primer for plastics which is good quality paint but odor sticks around a day or so.

https://my.vaisala.net/Vaisala%20Documents/Vaisala%20News%20Articles/VN160/VN160_New_Radiation_Shield_Models_DTR502B_and_DTR503A.pdf

Problem with spray paints is they are all high in VOCs which is not good for the sensor. You can find reduced VOC spray paint, but it's still not "low" in VOCs and I'd question the quality (flaking).
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: jerryg on August 07, 2018, 08:32:24 AM
Comparing shields is really a tough thing to do, i was thinking about the davis fars and in their comparison test they state the error was no more than say .6f higher than the rm young but you have to input the rm young also has an error of say .5f so your davis fars error could be over 1 degree and still be in spec. This is why my wondering about the pro readings with some wind blowing always being lower than the fars could mean the pro is closer to the actual temp and the fars is showing that potential 1f degree error. The test you show could be against a really good fars with great specs and that .9 with no wind would be great specs, after all we are talking about a cost effective shield that gives good results unless there is no wind and even then usable temps. We need to keep in mind these test are under the most severe conditions as far as no wind and high isolation conditions which only occur at certain times. Where i live the wind generally blows during the day and only lays at night but with no sun at night no heating effect. So it is really dependent on your location and wind conditions that will determine how well any given shield works. What is good for me may not work for you. Even the best fars have a temp rise error at max isolation and low wind. I was looking at the one they use for the climate network that cost 750 smackers and it has a low but it is there temp error. When it comes to daytime temp readings i use the nighttime temp comparison between the three shields and they never vary more than a tenth at night so any difference during the day is due to the shield itself and how it handles the varying conditions.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: jerryg on August 07, 2018, 08:51:36 AM
I think that since the pro seems to perform slightly better than my fars i am going to do some head to head comparison between the pro and the standard shields. I will have to put a 75 sensor in the standard shield for the comparison. I guess i could see if what i suspect is that a davis sensor could be cut down to fit inside a pro shield, the worse that could happen is i have a mutilated 31 lol.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: jerryg on August 07, 2018, 09:02:47 AM
To start still dark and no wind pro and standard showing 73.7  now at 8 am wind 2 mph and sunny skies pro is 79.1 and standard is 79.3 . More later.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: dendrite on August 07, 2018, 09:36:32 AM
Comparing shields is really a tough thing to do, i was thinking about the davis fars and in their comparison test they state the error was no more than say .6f higher than the rm young but you have to input the rm young also has an error of say .5f so your davis fars error could be over 1 degree and still be in spec. This is why my wondering about the pro readings with some wind blowing always being lower than the fars could mean the pro is closer to the actual temp and the fars is showing that potential 1f degree error. The test you show could be against a really good fars with great specs and that .9 with no wind would be great specs, after all we are talking about a cost effective shield that gives good results unless there is no wind and even then usable temps. We need to keep in mind these test are under the most severe conditions as far as no wind and high isolation conditions which only occur at certain times. Where i live the wind generally blows during the day and only lays at night but with no sun at night no heating effect. So it is really dependent on your location and wind conditions that will determine how well any given shield works. What is good for me may not work for you. Even the best fars have a temp rise error at max isolation and low wind. I was looking at the one they use for the climate network that cost 750 smackers and it has a low but it is there temp error. When it comes to daytime temp readings i use the nighttime temp comparison between the three shields and they never vary more than a tenth at night so any difference during the day is due to the shield itself and how it handles the varying conditions.
You use the stock fan in your FARS, correct? Have you tried comparing 2 Davis FARS -- one with a stock fan and one with more CFMs?
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: jerryg on August 07, 2018, 10:06:03 AM
Yes i did for some time and after having sensor failures because of moisture problems i went back to the davis set up because of the lower fan speed at night. This is the second morning that i have cut the fan off at night and got the same results much better readings in the mornin g that follows the other shields pretty well and not lagging behind for an up to an hour. I really think a fars if pretty tough on sensors in high humidity areas and i plan on running the pro shield for good. At 9 am the standard was 84.6 and the pro was 84.4 with winds 4-6 mph and still sunny.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: dendrite on August 07, 2018, 10:15:31 AM
Yes i did for some time and after having sensor failures because of moisture problems i went back to the davis set up because of the lower fan speed at night. This is the second morning that i have cut the fan off at night and got the same results much better readings in the mornin g that follows the other shields pretty well and not lagging behind for an up to an hour. I really think a fars if pretty tough on sensors in high humidity areas and i plan on running the pro shield for good. At 9 am the standard was 84.6 and the pro was 84.4 with winds 4-6 mph and still sunny.
It's interesting that you fine the RH lags in the morning with a FARS. Even with dewpoints near 70F, I've always found the opposite.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: dendrite on August 07, 2018, 10:18:11 AM
To start still dark and no wind pro and standard showing 73.7  now at 8 am wind 2 mph and sunny skies pro is 79.1 and standard is 79.3 . More later.
Just saw CRP is 83/81 right now. I don't know how you guys handle that down there.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: hwcorder on August 07, 2018, 10:30:49 AM
I have had my modified 75 in a  Meteoshield Pro for several days now with the stock Davis filter.  Here is my station dw5686 if you want to follow along with my stats compared to MADIS and two ASOS stations one 5 miles east (CLT) and the other 8miles southwest (AKH). I also upload to WxUnderground if you want to follow my data more in real time.

https://weather.gladstonefamily.net/site/D5686
https://www.wunderground.com/personal-weather-station/dashboard?ID=KNCBELMO18#history

So far I'm very happy as it seems my CWOP stats haven't changed very much at all. Perhaps running just .2F to .3F warmer compared to other stations than I used to. When comparing highs and lows I to local ASOS I go back and look at my one minute data and find the 5min running avg for the high and low for the day.  I think this is important that you do this since when comparing your readings with ASOS as it smooths out temperature data this way.  Anyhow, I have been running either even or one degree cooler than my local ASOS stations which is on par when I was running a davis FARS with stock fan, actually the replacement 3V motor from Nichibo.

Weather has been great for testing except for cloud cover.  Hot humid afternoons with light winds, but with scattered to broken layers. Want to eventually get around to some side by side testing with my FARS but from what jerryg has found in his testing it sounds like both the meteoshields and especially the pro may be promising alternatives to aspirated shields.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 07, 2018, 10:32:22 AM
To start still dark and no wind pro and standard showing 73.7  now at 8 am wind 2 mph and sunny skies pro is 79.1 and standard is 79.3 . More later.
Just saw CRP is 83/81 right now. I don't know how you guys handle that down there.

I've lived on the gulf before when I was a kid and remember it was the only place I sweated alot...Absolutely there is no evaporation so any moisture turns into liquid. 
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 07, 2018, 10:57:31 AM
I think it's important inside of these shields be non reflective flat black. Why they didn't' do it on standard shield? Maybe selling point for the more expensive pro model.
Vaisala does their new shields this way, it's almost become a standard now for absorbing accumulated heat thus eliminating the  possible warming inside the shield.

I was testing black spray paints yesterday and figured out you can accelerate the drying time substantially reducing odor by using a hair dryer. I'm going to look at hardware stores today for some Krylon Fusion black silk. This paint claims to work well on plastic and 10 minute dry times. I currently have the Valspar includes primer for plastics which is good quality paint but odor sticks around a day or so.

https://my.vaisala.net/Vaisala%20Documents/Vaisala%20News%20Articles/VN160/VN160_New_Radiation_Shield_Models_DTR502B_and_DTR503A.pdf

Problem with spray paints is they are all high in VOCs which is not good for the sensor. You can find reduced VOC spray paint, but it's still not "low" in VOCs and I'd question the quality (flaking).


I've checked for low VOC spray paint for plastic and can't find any.
What I read about the VOC's once paint is dry they stop emitting but it could be days maybe weeks depending.   One of the checks sensirion mentioned was if odor is present especially strong it can damage humidity sensor.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 07, 2018, 11:09:50 AM
This is why my wondering about the pro readings with some wind blowing always being lower than the fars could mean the pro is closer to the actual temp and the fars is showing that potential 1f degree error.

The WMO test on page 1 knocked the Davis FARS shield down for reading warmer vs reference shield with wind. Not sure how much wind it takes before the weak fan wouldn't work. Not much is my guess.

You need all 3 shields with exact sensor so 2 more 75's for a good comparison. However problem is 11 and 15's never matched exact and the 75's not sure :?:  Different story with the SHT31's they all seem to match within .02f.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 07, 2018, 12:15:15 PM
I have had my modified 75 in a  Meteoshield Pro for several days now with the stock Davis filter.  Here is my station dw5686 if you want to follow along with my stats compared to MADIS and two ASOS stations one 5 miles east (CLT) and the other 8miles southwest (AKH). I also upload to WxUnderground if you want to follow my data more in real time.

https://weather.gladstonefamily.net/site/D5686
https://www.wunderground.com/personal-weather-station/dashboard?ID=KNCBELMO18#history

So far I'm very happy as it seems my CWOP stats haven't changed very much at all. Perhaps running just .2F to .3F warmer compared to other stations than I used to. When comparing highs and lows I to local ASOS I go back and look at my one minute data and find the 5min running avg for the high and low for the day.  I think this is important that you do this since when comparing your readings with ASOS as it smooths out temperature data this way.  Anyhow, I have been running either even or one degree cooler than my local ASOS stations which is on par when I was running a davis FARS with stock fan, actually the replacement 3V motor from Nichibo.

Weather has been great for testing except for cloud cover.  Hot humid afternoons with light winds, but with scattered to broken layers. Want to eventually get around to some side by side testing with my FARS but from what jerryg has found in his testing it sounds like both the meteoshields and especially the pro may be promising alternatives to aspirated shields.

Very nice so another with a pro.

Has me thinking do I want to change at least 1 shield coming to a pro?
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 07, 2018, 12:31:16 PM
Here are the hwcorder ASOS comparisons. Very good dewpoints also on 75.

https://mesowest.utah.edu/cgi-bin/droman/meso_base_dyn.cgi?stn=D5686&unit=0&timetype=LOCAL/
https://mesowest.utah.edu/cgi-bin/droman/meso_base_dyn.cgi?stn=KCLT
https://mesowest.utah.edu/cgi-bin/droman/meso_base_dyn.cgi?stn=KAKH
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: jgentry on August 07, 2018, 12:34:43 PM
I have had my modified 75 in a  Meteoshield Pro for several days now with the stock Davis filter.  Here is my station dw5686 if you want to follow along with my stats compared to MADIS and two ASOS stations one 5 miles east (CLT) and the other 8miles southwest (AKH). I also upload to WxUnderground if you want to follow my data more in real time.

https://weather.gladstonefamily.net/site/D5686
https://www.wunderground.com/personal-weather-station/dashboard?ID=KNCBELMO18#history

So far I'm very happy as it seems my CWOP stats haven't changed very much at all. Perhaps running just .2F to .3F warmer compared to other stations than I used to. When comparing highs and lows I to local ASOS I go back and look at my one minute data and find the 5min running avg for the high and low for the day.  I think this is important that you do this since when comparing your readings with ASOS as it smooths out temperature data this way.  Anyhow, I have been running either even or one degree cooler than my local ASOS stations which is on par when I was running a davis FARS with stock fan, actually the replacement 3V motor from Nichibo.

Weather has been great for testing except for cloud cover.  Hot humid afternoons with light winds, but with scattered to broken layers. Want to eventually get around to some side by side testing with my FARS but from what jerryg has found in his testing it sounds like both the meteoshields and especially the pro may be promising alternatives to aspirated shields.

Very nice so another with a pro.

Has me thinking do I want to change at least 1 shield coming to a pro?

As of now, thats what Im planning on doing. For me, it will help the humidity sensor and will not have to worry about all the maintenance stuff. From what I understand so far, as long as you get a little breeze during the daytime hours, youre in good shape.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 07, 2018, 12:50:57 PM
Can't find the Krylon fusion black silk but did find camo version may actually be better called ultra flat in dark brown.
Process of smell test now after drying with hair dryer.
Left is the Krylon fusion Ultra flat camo. These are the 1/2" conduit PVC standpipes I'll use for mounting the 31's inside the meteoshield standard.

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Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: jerryg on August 07, 2018, 02:19:49 PM
Just a quickie, i got a 31 to fit inside the pro, tight, but it will go when you whack off the excess board on the right side of the sensor.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 07, 2018, 03:11:15 PM
Just a quickie, i got a 31 to fit inside the pro, tight, but it will go when you whack off the excess board on the right side of the sensor.
Very nice now what do I do?  LOL
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: jerryg on August 07, 2018, 03:20:23 PM
I did not leave it in too long to see if the size caused any air flow problems was just for fit. I had the shield up and down a few times today trying stuff and just got it back on for good i hope. i fixed up my sensor board so that i can slide the tube out with the sensor attached so i don't have to take the base apart. Now i can adjust the sensor height but remove it to try a different one easily. So at 2:20 pro 89.8 and standard 90.0 wind 6 to 10 mph and partly cloudy.  Need to add the sky is cloudy right now so temps are closer than they would be if in sunshine.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: jerryg on August 07, 2018, 04:00:24 PM
3 pm still cloudy pro 91.1 standard 913 forgot to add wind 5-12 mph
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: jerryg on August 07, 2018, 05:11:26 PM
Update 4pm pro 91.0 standard 91.0 still cloudy and windy 12 to 16 mph
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: jerryg on August 07, 2018, 06:02:46 PM
Update 5pm pro 92.8 std 93.1 sunny winds 7-10 mph
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: jerryg on August 07, 2018, 07:03:22 PM
Update 6pm pro 91.0 standard 91.2 partly cloudy wind 5 to 12 mph
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 07, 2018, 07:26:16 PM
Thanks for updates Jerry. Any chance of a day when winds are near calm?
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: jerryg on August 07, 2018, 07:29:33 PM
Where i live it's not if the wind will blow but how high will the winds get lol. No more updates today this time of day they pretty much match each other without the sun influence nearly all shields are great lol.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 07, 2018, 07:39:54 PM
Here is todays test with passive 7714 vs fars. Sunny, wind speeds up just a little around 3-5 mph peak gust was 16 mph.
Both FARS and 7714 recorded exact 86.3 high.

It's clear the 7714 is a great little shield. Doesn't take much wind and performs just as well.
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Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: CW2274 on August 07, 2018, 07:49:13 PM
It's clear the 7714 is a great little shield. Doesn't take much wind and performs just as well.
No doubt that it's really good, but the thing is, if passive shields were that good, fans would have never been used in the first place.
It'll be a cold day in H E double hockey sticks before you see an ASOS with a passive shield.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: jerryg on August 07, 2018, 08:04:06 PM
That's true but it depends on how good your fars is doing, some are better than others. Just having a fan doesn't mean you have the best. Like i said davis compares theirs to the rm young and says withing .6 and rm specs out at .4 so davis could be 1 degree higher than air temp. Now i was wondering if rm young tests their shield over grass low wind at solar noon what are they using as a reference for the actual air temp, how is it measured at the test site to know what the air temp is at any given time. If they have a super accurate temp sensor what do they put it in to get the actual air temp? I want the perfect shield they use for calibration lol.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: CW2274 on August 07, 2018, 08:28:50 PM
That's true but it depends on how good your fars is doing, some are better than others. Just having a fan doesn't mean you have the best.
Of course! All I'm saying is that fans aren't going anywhere in high end measurements.
I would love to see the pro shield compare to my properly aspirated 24hr VP2 when the wind is >5 mph and temps in the 105F+. It could be fantastic, but it would have to be revolutionary (and it's obvious they're pitching exactly this) for me to even think of giving up my fan.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: hwcorder on August 07, 2018, 11:27:26 PM
It's clear the 7714 is a great little shield. Doesn't take much wind and performs just as well.
No doubt that it's really good, but the thing is, if passive shields were that good, fans would have never been used in the first place.
It'll be a cold day in H E double hockey sticks before you see an ASOS with a passive shield.

Passive shields have come a long way and with more and more automated stations going in remote locations the need for low maintenance equipment will require the technology to progress.  With that being said my old cotton region shelter was pretty good back in the day and that design has been around for ages.

Anyway, my high for the day in the Meteoshield Pro was 94F.  AKH to my west hit 93 and CLT to my east 92.  CLT seemed to sit at 91-92 for several hours this afternoon which was a little odd, possibly from a little more cloud cover than my location.  Will see what happens tomorrow as weather should be very similar to today.

The high did occur when winds became light or nearly calm so this could have been from a little solar heating. Like others I wonder if the big davis filter interrupts airflow within the sensor. chamber  I am actually working on converting an ink pin into a temp/hum probe using my 75 that will fit in the bottom opening.  Ordered a few different filter caps from Campbell Scientific and found one that works very well.  Just need to mount the wiring then weatherproof the connections.   
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 08, 2018, 05:29:32 AM
Something just came up from hwcorder post about using stock filter on modified 73. How about others?  I don't see a specifically made filter for these so do they even require a filter?  if so is it just some homebrew like wrapping sensor in davis type filter material?   
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: dendrite on August 08, 2018, 07:17:23 AM
Something just came up from hwcorder post about using stock filter on modified 73. How about others?  I don't see a specifically made filter for these so do they even require a filter?  if so is it just some homebrew like wrapping sensor in davis type filter material?
The Campbell Sci tem/hum probe uses the 75.

https://www.campbellsci.com/cs215-l (click "read more")


I'd assume that probe filter housing is available somewhere in accessories or replacement parts.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: dendrite on August 08, 2018, 07:23:18 AM
Heh...found this in the CS215-L manual. I assume this applies to all Sensirion sensors...

Quote
Measurement Below 0 C
The CS215 provides a humidity reading that is referenced to the saturated water vapor pressure above liquid water, even at temperatures below 0 C, where ice might form. This is the common way to express relative humidity and is as defined by the World Meteorological Organization. If an RH value is required to be referenced to ice, the CS215 readings will need to be corrected.
One consequence of using water as the reference is that the maximum humidity that will normally be output by the sensor for temperatures below freezing is as follows:
100% RH at 0 C
95% RH at 5 C
91% RH at 10 C
87% RH at 15 C
82% RH at 20 C
78% RH at 25 C
75% RH at 30 C
In practical terms this means that, for instance, at 20 C the air is effectively fully saturated when the sensor outputs 82% RH.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 08, 2018, 07:31:48 AM
Something just came up from hwcorder post about using stock filter on modified 73. How about others?  I don't see a specifically made filter for these so do they even require a filter?  if so is it just some homebrew like wrapping sensor in davis type filter material?
The Campbell Sci tem/hum probe uses the 75.

https://www.campbellsci.com/cs215-l (click "read more")


I'd assume that probe filter housing is available somewhere in accessories or replacement parts.

The filter cap they use is https://www.campbellsci.com/p18142 and you request a quote. surely this isn't what most use is it? When they say request a quote it's beyond my price... :grin:
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 08, 2018, 07:39:29 AM
Found these https://www.aliexpress.com/item/2pcs-Waterproof-Temperature-and-humidity-sensor-shell-SHT10-SHT21-SHT15-shT11-sht20-SHT75-sensor-protective-sleeve/32725766858.html?spm=2114.search0104.3.16.7f3c5891DPRtm1&ws_ab_test=searchweb0_0,searchweb201602_1_10152_10151_10065_10344_10068_10130_10324_10342_10547_10325_10343_10546_10340_10548_10341_315_10545_10696_10084_531_10083_5011611_10618_10307_5011511_5723611_10059_100031_10103_10624_10623_10622_10621_10620,searchweb201603_6,ppcSwitch_5&algo_expid=125061b9-f6a7-4d33-be9e-ed1a5566bfc1-2&algo_pvid=125061b9-f6a7-4d33-be9e-ed1a5566bfc1&priceBeautifyAB=0

These guys have a custom mount. https://www.emesystems.com/sht75pg/main.html
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 08, 2018, 08:25:39 AM
Waiting for more ideas. In meantime why can't we just use the existing Davis material, use cotton thread and tie material around the SHT75 sensor. Don't know why it wouldn't work.  :idea:
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: jerryg on August 08, 2018, 08:30:00 AM
Looks pretty good so i order some, hope they are as shown lol.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 08, 2018, 08:49:27 AM
Looks pretty good so i order some, hope they are as shown lol.
Same here, used paypal. I heard they are trustworthy, some people buy cameras all the time.
19-39 days is a wait however.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: jerryg on August 08, 2018, 09:07:38 AM
Well waiting is what we do a lot of messing with this stuff, try something new then wait with fingers crossed lol. It will be neat if the filter end could be fastened to the tube and cover the 75. Would make a nice probe. I am just trying to decide if i want to put the 31 in the pro and see how it performs, i removed the little sliver of board next to where the cable is, every little bit helps it to fit. So now all the excess board is removed right next to the stuff davis covers the board with. It doesn't take too long to change it, just hate messing with those little 7 mm nuts, my fingers just refuse to hold them secure, slippery little devils lol. It would be nice to know how it shapes out with the 75 being phased out.

Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: hwcorder on August 08, 2018, 09:09:53 AM
Something just came up from hwcorder post about using stock filter on modified 73. How about others?  I don't see a specifically made filter for these so do they even require a filter?  if so is it just some homebrew like wrapping sensor in davis type filter material?
The Campbell Sci tem/hum probe uses the 75.

https://www.campbellsci.com/cs215-l (click "read more")


I'd assume that probe filter housing is available somewhere in accessories or replacement parts.

The filter cap they use is https://www.campbellsci.com/p18142 and you request a quote. surely this isn't what most use is it? When they say request a quote it's beyond my price... :grin:

Most probes do use a filter similar to these. As far as the request a quote thing goes I think they just want you to sign up for an account.  I have ordered several things from Campbell so I have one and can get online princing.  The filter cap I planning on using is a replacement filter cap for a Vaisala HMP60 probe. Most of these run 20-45 dollars though they run up over $70 for the HMP155.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: dendrite on August 08, 2018, 09:28:46 AM
It would be nice to know how it shapes out with the 75 being phased out.
Really need Sensirion to spit out a pin SHT35-LSS. Maybe a few of us could email them some encouragement. ;)
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: jerryg on August 08, 2018, 10:29:02 AM
OK i am now running the 31 in the pro shield, it fits ok with the excess board removed so will watch it today and see how it goes. Everything looks good compared with the other sensors so far. It will be nice if everything goes well.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: jgentry on August 08, 2018, 11:06:25 AM
Something just came up from hwcorder post about using stock filter on modified 73. How about others?  I don't see a specifically made filter for these so do they even require a filter?  if so is it just some homebrew like wrapping sensor in davis type filter material?
The Campbell Sci tem/hum probe uses the 75.

https://www.campbellsci.com/cs215-l (click "read more")


I'd assume that probe filter housing is available somewhere in accessories or replacement parts.

The filter cap they use is https://www.campbellsci.com/p18142 and you request a quote. surely this isn't what most use is it? When they say request a quote it's beyond my price... :grin:

Most probes do use a filter similar to these. As far as the request a quote thing goes I think they just want you to sign up for an account.  I have ordered several things from Campbell so I have one and can get online princing.  The filter cap I planning on using is a replacement filter cap for a Vaisala HMP60 probe. Most of these run 20-45 dollars though they run up over $70 for the HMP155.

Whats the advantages with that filter cap over Sensirions sf1 cap?
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 08, 2018, 12:07:21 PM
OK i am now running the 31 in the pro shield, it fits ok with the excess board removed so will watch it today and see how it goes. Everything looks good compared with the other sensors so far. It will be nice if everything goes well.

With or without stock filter cap?
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: hwcorder on August 08, 2018, 12:12:17 PM
Something just came up from hwcorder post about using stock filter on modified 73. How about others?  I don't see a specifically made filter for these so do they even require a filter?  if so is it just some homebrew like wrapping sensor in davis type filter material?
The Campbell Sci tem/hum probe uses the 75.

https://www.campbellsci.com/cs215-l (click "read more")


I'd assume that probe filter housing is available somewhere in accessories or replacement parts.

The filter cap they use is https://www.campbellsci.com/p18142 and you request a quote. surely this isn't what most use is it? When they say request a quote it's beyond my price... :grin:

Most probes do use a filter similar to these. As far as the request a quote thing goes I think they just want you to sign up for an account.  I have ordered several things from Campbell so I have one and can get online princing.  The filter cap I planning on using is a replacement filter cap for a Vaisala HMP60 probe. Most of these run 20-45 dollars though they run up over $70 for the HMP155.

Whats the advantages with that filter cap over Sensirions sf1 cap?

As far as actual performance goes probably none. However you would have to get kind creative when trying to mount a SF1 to a SHT75. These types of filter caps screw in so getting to the sensor is needed is much easier.  You also dont have to worry about adhesives and damaging the sensor with outgasing.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: jerryg on August 08, 2018, 12:26:10 PM
Using the sf2.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 08, 2018, 01:19:33 PM
Thanks Jerry, your winds are down today but you look rather cloudy looking at solar around 218 W/m
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: jerryg on August 08, 2018, 01:46:31 PM
Yeah can not catch a break, cloudy light rain and wind.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 08, 2018, 04:39:22 PM
Those filters linked above from Allied for SHT75, has OD 15mm (.59") should fit inside 1/2" Sched.40 pvc conduit with actual ID on average is .622".
Makes for easy standpipe adjustment for sensor height .  I was thinking keep it lower toward bottom of shield around 3.5-4".
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Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: jerryg on August 08, 2018, 06:01:17 PM
Ok just got through swapping the 31 out with the 75. I also remounted the two barani shields, i had put them up above the davis base which was at 7 feet, did not want to put too much work into it until i was sure what i was going to do. I now have both shields mount in the same place where the fars shields were. One thing if you put the shield up next to the base the stock cable will plug into the iss with just a little playing around. The 31 worked just fine and tracked like it should so the sensor can be used with a little care and a hacksaw. The sun finally came out awhile ago and the winds were light so got a quick look at the difference between the two shields and the worst i saw was the standard ran at times about .9 degrees warmer but when the wind picked up it was on the way down. The pro at the same time was running .4 degrees lower than the fars. While i had the 75 out i did a real good check on temp and it was right on the money. I now have the pro mounted permanently and will use it for my main station. I will continue to try different sensors and stuff in the standard shield. It is really nice having the sensor set up as a probe, easy to slide out of the shield and put back in, no need to remove the shield.  Right now pro is at 88.5 fars at 88.9  and standard 89.3. winds 5 to 7 mph.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 08, 2018, 07:23:08 PM
the winds were light so got a quick look at the difference between the two shields and the worst i saw was the standard ran at times about .9 degrees warmer  The pro at the same time was running .4 degrees lower than the fars.

So you are saying 1.3 difference between Pro and standard?
Did the pro run the same .4 below FARS light wind and sun with the 31 as it was with the 75?
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: jerryg on August 08, 2018, 07:36:38 PM
The difference was .8 degrees and the 75 and 31 run about the same as far as temp goes but humidity changes were faster with the 75. So far it looks like using the standard shield isn't too bad compared to the fars and that's the main thing to note as you would be replacing the fars. The pro shield just seems to run a little lower and worst case runs the same as the fars. In any case with some wind the differences just aren't that great. If i lived in an area where there are a lot of days with light winds i would consider the pro. I would think in a place like England where they get a lot of cloudy days the standard would work real well. Maybe up north where the solar energy isn't as strong as down here it might even out. There are still a lot of questions to be answered in the long run but my results look pretty good for the area i live in. I like how fast the humidity response is compared to the fars, i have seen the pro drop 5 to 6% before the fars went down.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 08, 2018, 08:06:32 PM
Well I might change my order to 1 pro shield if 31 will fit and just leave the 7714 at windy remote site. Not sure standard is any better anyway from your results.

Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: Bobvelle on August 08, 2018, 08:20:45 PM
A man with a thermometer knows what the temperature is. A man with two thermometers is never sure.  :idea:

 =D&gt; :lol: :lol:

Thanks for that! I've never heard it before..and I have been laughing about it all day.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: jerryg on August 08, 2018, 08:44:18 PM
I fits all i did was put a small piece of paper over the sensor and a piece of tape to secure it to keep any sawing dust out of the sensor then i turned it over and all the area that is covered over by davis is left intact and i just used the edge of the black goop as a guide an sawed off the unused portion of the board to the right and took the 1/8 inch off the side where the cable is attached. You still have one mounting hole left on that side if you need to use it in a davis setup but you lose the hole for one side of the davis filter.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: jerryg on August 09, 2018, 12:29:08 PM
Just got through setting up my rm young shield with my calibrated digital meter with probe and comparing it to the pro. First it's too hot to stand out by the shields and do it lol. But i quickly found out trying to use the console to measure with is nuts, update is too slow. I have a modified hand held temp/humidity meter that reads the sht sensor in real time. So with that in hand and a extension cable to run the sensor over to the hand held meter and light winds at times to 6 to 8 mph i began my slowly melting from the heat test. The real time reading makes it a little hard to do a direct comparison because the sensor itself updates the data about every 3 seconds. The temp was running around 90 degrees with winds of 7 mph and when the wind laid the rmy rose to 91.2 and the pro 90.4 then the wind picked up and the rmy dropped to 88.9 while the pro dropped to 89.4 and was going down slowly and then with wind again the they were both showing around 90.2 for a while. I was surprised to see the industry standard shield with heavy air flow go up over a degree when the winds were about 1 mph and how quickly it fell when the winds picked back up. Even the high dollar rmy is dependent on the wind blowing, heck acted more like the pro and how it handles wind. This is the first time i made a direct comparison like that. I could not believe that with the high air flow of the rmy that it would be so wind speed dependent. Heck that 1 degree swing was more than the pro showed. Maybe the pro being designed for low wind speed made the difference. Very interesting test to say the least.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 09, 2018, 01:57:36 PM
As much as you like testing Jerry you should own the envoy8x and get another data logger.
With that setup all you need is several ISS units and you have all the information on computer. The envoy8x is no longer made but several sellers still have in stock. It's my favorite for looking at multiple stations and will export directly to excel and make nice graphs. 

Oh almost forgot, Thanks to you guys that determined with a little trim jop the 31 would fit inside the pro shield,  changed my order to include 1 pro station.  \:D/
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 09, 2018, 02:05:07 PM
If anyone else ordered a meteoshield shield they are being shipped to customers north American today.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: jerryg on August 09, 2018, 03:11:06 PM
Too much testing lol but man with the temp up to 95 and light winds pretty rough hanging around outside and got too much money tied up in this stuff already. We finally got a day of sunshine and at times light winds and when the winds are almost calm the difference shows up between the pro and standard but it really doesn't take much wind to get them close. Since the test with the rm young surprised me i am seriously thinking about mounting the temp. probe inside a davis shield and see if the wind has the same results on temp variations. Curiosity makes this testing tough lol.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: openvista on August 09, 2018, 03:44:54 PM
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Earlier this week I received and set up the Davis 7714 shield with a 31 sensor. It's about 8ft away and 1.5ft lower than my FARS (whose intake is at 5' 2").

This is the 3rd calm, sunny day in a row. Temps in the 70s mainly. Winds <3mph (~1 m/s) at 30ft (virtually calm at ground level).   

I put some data into a spreadsheet and found that around solar noon the difference between the two shields averages around 3-3.5F, sometimes 4F or more (passive sensor running higher). Overall, the average daytime difference is about 2-2.5F. The only time the shields are within 1F during the midday and afternoon is when heavy clouds pass overhead.

The height differential between the shields may play some role. However, raising the shield to 5ft won't produce much additional wind because the measurement location (like so many backyard weather stations) is hemmed in by taller structures on multiple sides.

Overnight lows are a bit lower (0.5 - 1F) on clear nights in the 7714, but not enough to balance out the false highs. On nights when skies are cloudy and winds are greater than 3mph, the shields run within 0.5F of each other (within sensor's margin of error).

This is about the same performance as I was getting from the stock VP2 passive shield mounted in the same location. I'm hopeful, with just a bit more wind coming from a prevailing direction (rather than a sheltered direction), the 7714 will outperform the stock passive shield. Unfortunately, those conditions have yet to happen. And there's no end in sight to the days with 10m winds at or below 5mph.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 09, 2018, 03:50:10 PM
Those tiny SF2  filters came in so wanted to practice installing with bad 31 sensor. Filter slid slightly no room for any error and ended up getting glue on 31.  ](*,)  Good thing it was a bad already.

Enough of that, going with original :idea:
Much safer method for me, just cut corner of stock Davis filter and using the universal eco glue supertite was able to safely add filter nice and tight as good as stock without the bulky filter body.  Just ran small bead of glue (not thick) and works great. No smell or damaging chemicals with this glue and drys fast.

Doing a humidity test now. This was one of reconditioned 96% sensors just want to make sure it still reaches. It will be a spare for any of the passive shields if needed.
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Something else for cutting these Davis sensor boards down if you have a set of metal tin snips very fast and clean cuts.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: openvista on August 09, 2018, 03:52:41 PM
As of now (3:50PM EDT), about 2 hours after solar noon (1:55PM local time), winds average 2mph at 10m, skies are clear. FARS temp: 69.1 & 7714 temp: 73.1. This is typical of what I've been seeing and may even worsen in late afternoon when the sun angle is more directly focused on the western side of the passive shield.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: CW2274 on August 09, 2018, 04:01:03 PM
Those tiny SF2  filters came in so wanted to practice installing with bad 31 sensor. Filter slid slightly no room for any error and ended up getting glue on 31.  ](*,)  Good thing it was a bad already.

Enough of that, going with original :idea:
Much safer method for me, just cut corner of stock Davis filter and using the universal eco glue supertite was able to safely add filter nice and tight as good as stock without the bulky filter body.  Just ran small bead of glue (not thick) and works great. No smell or damaging chemicals with this glue and drys fast.

Doing a humidity test now. This was one of reconditioned 96% sensors just want to make sure it still reaches. It will be a spare for any of the passive shields if needed.
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Something else for cutting these Davis sensor boards down if you have a set of metal tin snips very fast and clean cuts.
I just wrapped a thin braided wire around mine and cinched it down. With the rubbery base, I'm confident I have a waterproof seal. Now, whether I need that or not.....
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: CW2274 on August 09, 2018, 04:03:27 PM
As of now (3:50PM EDT), about 2 hours after solar noon (1:55PM local time), winds average 2mph at 10m, skies are clear. FARS temp: 69.1 & 7714 temp: 73.1. This is typical of what I've been seeing and may even worsen in late afternoon when the sun angle is more directly focused on the western side of the passive shield.
FARS rule. :-P ;)
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: jerryg on August 09, 2018, 04:11:28 PM
I thought about using snips but was afraid the board may break rather than cut and didn't have a bad board left to practice on, good to know, less messy and faster.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 09, 2018, 04:12:19 PM
[ You are not allowed to view attachments ]

Earlier this week I received and set up the Davis 7714 shield with a 31 sensor. It's about 8ft away and 1.5ft lower than my FARS (whose intake is at 5' 2").

This is the 3rd calm, sunny day in a row. Temps in the 70s mainly. Winds <3mph (~1 m/s) at 30ft (virtually calm at ground level).   

I put some data into a spreadsheet and found that around solar noon the difference between the two shields averages around 3-3.5F, sometimes 4F or more (passive sensor running higher). Overall, the average daytime difference is about 2-2.5F. The only time the shields are within 1F during the midday and afternoon is when heavy clouds pass overhead.

The height differential between the shields may play some role. However, raising the shield a meter or so won't produce much additional wind because the measurement location (like so many backyard weather stations) is hemmed in by taller structures on multiple sides.

Overnight lows are a bit lower (0.5 - 1F) on clear nights in the 7714, but not enough to balance out the false highs. On nights when skies are cloudy and winds are greater than 3mph, the shields run within 0.5F of each other (within sensor's margin of error).

This is about the same performance as I was getting from the stock VP2 passive shield mounted in the same location. I'm hopeful, with just a bit more wind coming from a prevailing direction (rather than a sheltered direction), the 7714 will outperform the stock passive shield. Unfortunately, those conditions have yet to happen. And there's no end in sight to the days with 10m winds at or below 5mph.

WOW! Bad numbers there wonder why I'm getting much better results. My max has only been +2 but it was during swing and max difference was 1.6. Not great but all other days have been really good.
The Davis Pro now I was seeing similar +2-4 difference daily.
My shields are only few feet apart at same elevation could it be something to do with being painted black inside? I don't know if you want to but if you do the Krylon fusion has less odor than other paints I tested. Still there but faint, I think the Ultra Flat camo dark brown would work best.

Todays data looks great light winds and sunny.
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Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: jerryg on August 09, 2018, 04:33:47 PM
Pictures of final position of shields and stuff.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: openvista on August 09, 2018, 04:35:50 PM
WOW! Bad numbers there wonder why I'm getting much better results.

Because of your optimal siting, even light winds will be felt to some degree at shield level. Not so much in my location. It's pretty safe to assume I have calm winds during most of the test period near ground level. I've walked around out there several times, looked up and I've seen the cups slowly turning at 30ft, but felt no breeze standing next to the shield.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: dendrite on August 09, 2018, 04:37:58 PM
As of now (3:50PM EDT), about 2 hours after solar noon (1:55PM local time), winds average 2mph at 10m, skies are clear. FARS temp: 69.1 & 7714 temp: 73.1. This is typical of what I've been seeing and may even worsen in late afternoon when the sun angle is more directly focused on the western side of the passive shield.
FARS rule. :-P ;)
I'm reporting this passive aggressive post.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 09, 2018, 04:39:43 PM
WOW! Bad numbers there wonder why I'm getting much better results.

Because of your optimal siting, even light winds will be felt to some degree at shield level. Not so much in my location. It's pretty safe to assume I have calm winds during most of the test period near ground level. I've walked around out there several times, looked up and seen the cups slowly turning at 30ft, but felt no breeze standing next to the shield.

If it's a new 31 did you remember to do the -.9 offset if using pre Jan 2016 transmitter. Only reason I ask is I have a mix of iss transmitters and have done exactly that before.  :-)
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: openvista on August 09, 2018, 04:54:38 PM
If it's a new 31 did you remember to do the -.9 offset if using pre Jan 2016 transmitter. Only reason I ask is I have a mix of iss transmitters and have done exactly that before.  :-)

Yup, I put the offset in at the very beginning (as I had an SHT15 in the stock shield before that).
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: dendrite on August 09, 2018, 04:56:57 PM
WOW! Bad numbers there wonder why I'm getting much better results.

Because of your optimal siting, even light winds will be felt to some degree at shield level. Not so much in my location. It's pretty safe to assume I have calm winds during most of the test period near ground level. I've walked around out there several times, looked up and seen the cups slowly turning at 30ft, but felt no breeze standing next to the shield.

If it's a new 31 did you remember to do the -.9 offset if using pre Jan 2016 transmitter. Only reason I ask is I have a mix of iss transmitters and have done exactly that before.  :-)

Samething here...resorted to labelling the ISS covers "old" and "new" to keep things straight.
Good idea. It gets even harder to keep track when switching between 31s and 75s.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: CW2274 on August 09, 2018, 05:16:36 PM
As of now (3:50PM EDT), about 2 hours after solar noon (1:55PM local time), winds average 2mph at 10m, skies are clear. FARS temp: 69.1 & 7714 temp: 73.1. This is typical of what I've been seeing and may even worsen in late afternoon when the sun angle is more directly focused on the western side of the passive shield.
FARS rule. :-P ;)
I'm reporting this passive aggressive post.
:-$
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 09, 2018, 05:36:12 PM
Pictures of final position of shields and stuff.

I think you need a couple more shields  :grin:
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: CW2274 on August 09, 2018, 05:48:59 PM
Pictures of final position of shields and stuff.

I think you need a couple more shields  :grin:
:lol: Look who's talking... :lol:
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: openvista on August 09, 2018, 06:04:40 PM
Just processed my 1 minute archives in each shield from 10AM to 5PM today.

Results (avg wind 1.9mph at 30ft; clear skies during test period):

7755 avg temp: 69.7 (FARS)
7714 avg temp: 71.9 (passive)
Difference: 2.2F

Difference between high temps: 1.9F

Current conditions at 6:03PM EDT: 73.1 (FARS), 76.7 (7714) with 1mph wind.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: openvista on August 09, 2018, 06:11:17 PM
I should add that I have a custom AC fan in my FARS that generates 24 CFM or about 444 LFM (2.25 m/s).
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: jerryg on August 09, 2018, 06:42:00 PM
Here is a link to site that has some good pictures of the shields and explains how it works https://creativepool.com/jan-barani/projects/meteoshield-professional
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 10, 2018, 08:53:10 PM
Added second sht31 sensor into 7714 to see if location made any difference inside shield. Didn't see anything, with both the same and .8 max difference from FARS. Another really good day for 7714.

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Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 11, 2018, 03:36:12 AM
Started thinking about this for getting the cut down board on SHT31 inside when I placed the order for PRO Shield the larger adapter wasn't available 26mm only the 13-20mm. At the time never thought much of it thinking it was just the pipe diameter on bottom, inside the shield would be the same size but now I wonder.
Are these Pro shields all the same inside? What size adapter did you order? Something that has never mentioned if even relevant.  I asked this question to allMeto but haven't received anything back yet.
Thanks
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 11, 2018, 11:39:21 AM
OK i am now running the 31 in the pro shield, it fits ok with the excess board removed so will watch it today and see how it goes. Everything looks good compared with the other sensors so far. It will be nice if everything goes well.

Jerry need to know what adapter you have. When I ordered the  option for 26mm was not available.
Do you know if the 20mm will work?
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: jerryg on August 11, 2018, 11:41:16 AM
My thought was it just allows you to put a slightly larger probe inside the shield without increasing the interior dimensions of the chamber. Could be there may be a slightly larger probe that is used that needs the slightly larger clamp. I am using the regular clamp and with it being 3/4 inch i just set the 31 sensor on top of the tube and sealed the bottom to hold it in place. Keep in mind that the cable coming off of the sensor is offset to one side so the sensor can not be put center on the tube, the larger tube might allow it to center up more but have no way of knowing that but it might.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 11, 2018, 11:54:02 AM
My thought was it just allows you to put a slightly larger probe inside the shield without increasing the interior dimensions of the chamber. Could be there may be a slightly larger probe that is used that needs the slightly larger clamp.

Hope so. That was my original thought also about adapter but wanted to make sure.
I've got no response from them in 24 hours so just sent another email today asking for some clarity and explaining again my intentions of using shield is with Davis cutdown sensor so there is no confusion what shield I need, if they are actually different inside.
The Pro shield still hasn't shipped the standard did go out Thursday.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 11, 2018, 07:33:55 PM
Another stellar day for 7714 with double sensors recording same exact temperature +.4F warmer on high temperature, -.2F on low. Not greatest test day however with wind reaching 10 mph at 40' at times.


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Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 12, 2018, 04:42:31 PM
Received email from allmeteo concerning the chamber size on the Pro Meteoshield. They are all the same 44mm inside sensor chamber. The adapter size only pertains to clamp size.
They said they may add to specs so those doing unconventional setups will know what they have.   
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 13, 2018, 06:50:45 PM
Both Meteoshields came in Pro and standard.
I've had all 4 shields in service for about 30 minutes. Not best time of day because of developing shadows. What I see so far.  Wind is  currently around 4 mph with occasional gust to 15 mph at 30'.

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Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: jerryg on August 13, 2018, 07:02:36 PM
Are you running the new 31 and any problems fitting it in the shield?
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 13, 2018, 07:18:19 PM
Yes all same SHT31, only stock filter in FARS. Others are my flat glue on (no VOC) cut down board custom job. LOL  :grin:
The standard shield is already black inside so no paint needed but looking like the 7714 is doing slightly better constantly now. Not jumping to conclusion however need a better low wind test day.

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Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: CW2274 on August 13, 2018, 07:25:17 PM
The Pro is really looking like the real deal, especially for folks who don't want to mess with a fan (that won't be me).
It's obvious the Pro can handle it's own with a slight breeze, now the "no wind, lotsa sun" scenario is obviously needed for the "are fans obsolete" test. :-"
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 13, 2018, 07:32:50 PM
The Pro is really looking like the real deal, especially for folks who don't want to mess with a fan (that won't be me).
It's obvious the Pro can handle it's own with a slight breeze, now the "no wind, lotsa sun" scenario is obviously needed for the "are fans obsolete" test. :-"

Think so too. No doubt the big question is how it performs on calm days. 
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 14, 2018, 12:52:36 PM
Let's try this test again.

I had to rearrange shields even added a tripod to separate now all 4 are catching approximately same amount of sun exposure from south. The earlier arrangement left the 7714 and FARS in early morning shade.  My bad on setup.

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Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 14, 2018, 01:18:12 PM
Looks better with all lined up together facing south. We do have a slight NE wind so far making right side shield 7714 on wind direction side and mounted about 6" higher than other shields 5'8" vs 5'. Also running coolest currently.

For wind speeds on this test anemometer is connected to standard meteoshield TX-3 is at 8' elevation just above shields. Ignore the Tx-2 at 30'

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Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 14, 2018, 02:55:29 PM
Saying this with tongue and cheek, is it possible the Davis shield does read low in low wind like the WMO study said?  The Pro is following airport like they are cloned.  #-o
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Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: jgentry on August 14, 2018, 03:14:35 PM
Saying this with tongue and cheek, is it possible the Davis shield does read low in low wind like the WMO study said?  The Pro is following airport like they are cloned.  #-o
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Probably so. The pro shield seems like the solution if you want to replace the FARS, more specifically, the Davis FARS. Planning on getting the pro shield soon.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 14, 2018, 03:23:27 PM
Saying this with tongue and cheek, is it possible the Davis shield does read low in low wind like the WMO study said?  The Pro is following airport like they are cloned.  #-o
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Probably so. The pro shield seems like the solution if you want to replace the FARS, more specifically, the Davis FARS. Planning on getting the pro shield soon.

I wouldn't do anything yet. Still very early on but I'm seeing pattern already with light winds the 7714 still doing the best and closest to the FARS. It's painted black inside just bottom and very top however with VOC paint which may damage sensor.

The Metoshield standard is really lagging behind I'm trying different sensor heights to no avail so far. 
 
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: CW2274 on August 14, 2018, 03:29:10 PM
Saying this with tongue and cheek, is it possible the Davis shield does read low in low wind like the WMO study said? The Pro is following airport like they are cloned.  #-o
Well then, the way I see it is that the Davis is more accurate just for this simple reason; how does a shield make the ambient air cooler than actually is??
Not saying it's not possible, I guess...
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 14, 2018, 03:50:27 PM
Saying this with tongue and cheek, is it possible the Davis shield does read low in low wind like the WMO study said? The Pro is following airport like they are cloned.  #-o
Well then, the way I see it is that the Davis is more accurate just for this simple reason; how does a shield make the ambient air cooler than actually is??
Not saying it's not possible, I guess...

The design with the triple walls could possibly be making some type of heat exchanger is only thing I can come up with. The outer air scavenging a little heat from inner wall and so forth x2 times. 

Updated the 7714 lowered so comparing at same elevations.
 
All 4 of these sht31 's matched exactly all night within .01 most of time prior to sunrise if anyone wonders.
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Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: safuser on August 14, 2018, 03:53:29 PM
Just got A Meteoshield Pro and working on putting in a SHT35.  See thread  http://www.wxforum.net/index.php?topic=34919.0
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 14, 2018, 04:22:49 PM
With clouds light wind they are pulling together as they should. Standard still a little lag.

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Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 14, 2018, 06:32:16 PM
Really bad day for testing with clouds, you would of expected these to run closer. The 7714 and Fars ran neck and neck, BUT the money shields  :-(     The shields were not aligned for same exposure until red line.

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Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: CW2274 on August 14, 2018, 06:38:06 PM
 :eek: So the newcomers were seeing more sun than the two Davis shields before noon? Even after, kinda looks like the 7714 is saying "if it ain't broke, don't fix it. Very interesting...

Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 14, 2018, 06:44:10 PM
:eek: So the newcomers were seeing more sun than the two Davis shields before noon? Even after, kinda looks like the 7714 is saying "if it ain't broke, don't fix it. Very interesting...

Yes they were exposed more, after 12 noon they all had equal sunshine what little we had. I have too much invested to give up so I've been messing with sensor height inside shields. The standard likes sensor up higher and pro down low from what I've seen so far.
Jerry might have the secret sauce for these if he shares.   [-o&lt;
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: CW2274 on August 14, 2018, 06:54:33 PM
:eek: So the newcomers were seeing more sun than the two Davis shields before noon? Even after, kinda looks like the 7714 is saying "if it ain't broke, don't fix it. Very interesting...
I have too much invested to give up
Of course all you testers are ultimately doing this for your own benefits, but don't think that the members here aren't very appreciative of yours and the others time and money spent for the benefit of all interested parties. =D&gt;
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: dendrite on August 14, 2018, 07:04:15 PM
:eek: So the newcomers were seeing more sun than the two Davis shields before noon? Even after, kinda looks like the 7714 is saying "if it ain't broke, don't fix it. Very interesting...
I have too much invested to give up
Of course all you testers are ultimately doing this for your own benefits, but don't think that the members here aren't very appreciative of yours and the others time and money spent for the benefit of all interested parties. =D&gt;
I was about to bite on a Pro, but Randy's tests have given me pause.

Many thanks from me as well. I love seeing everyone's experiments.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: openvista on August 14, 2018, 07:09:11 PM
I would not suspect the 7755 FARS shield of running cooler than true air temp. Heat exchangers use heat conducting metal not insulating plastic. The Venturi effect, assuming its more than negligible, would apply to all shields since they restrict air flow greatly compared to the surrounding environment. Think of the aspirated R.M. Young shield and how it compares in size and design to the 7755 with inner and outer chambers. How would that not also suffer from running "colder" than ambient temps?

Given that you fixed the biggest flaw in the 7755 with an AC fan (the stock fan runs less than 1 m/s whereas your fan puts out north of 2 m/s), I'd still suspect that's the reference in this scenario.

 




 
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: openvista on August 14, 2018, 07:29:44 PM
By the way, I elevated the 7714 shield today to 20 feet on an eave mount above my garage (by about 6-7ft). I know, that's not a good comparison to a shield at 5ft, but wouldn't you know it, after that, it ran neck and neck with my FARS (inside the specs for the 31s).

Admittedly today was a mostly cloudy day. Previously, though, during cloudy periods when the passive shield was closer to the ground, it ran warm by at least a degree (if not two) during the day which made no sense other than bad siting. When the sun made an occasional appearance today, both shields ran extremely close with the new arrangement.

Thing is, I don't have a good spot for another shield at 5ft AGL without compromising my main station, which I'm not going to do.

Even though it's not technically a valid test, I will report results once sunnier conditions arrive (maybe tomorrow but more likely Thursday). This may be a decent workaround solution for people with limited siting options and/or a sheltered yard who don't want to bother with a FARS.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: CW2274 on August 14, 2018, 07:33:37 PM
The Venturi effect, assuming its more than negligible, would apply to all shields since they restrict air flow greatly compared to the surrounding environment.
Not that it's a measurable factor to our sensors, but not only, compressed air heats, not cools.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: openvista on August 14, 2018, 07:48:40 PM
The Venturi effect, assuming its more than negligible, would apply to all shields since they restrict air flow greatly compared to the surrounding environment.
Not that it's a measurable factor to our sensors, but not only, compressed air heats, not cools.

I believe the thinking with Venturi is that as a mass of air enters a constriction (inner chamber of shield in this instance), the pressure actually drops as it elongates. And I guess people are assuming that a drop in pressure corresponds to a drop in temperature? If this is true, then someone needs to explain why air expands as it warms and drops in pressure (unless constrained on all sides like in a pressure cooker).
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: hwcorder on August 14, 2018, 09:32:56 PM
The Venturi effect, assuming its more than negligible, would apply to all shields since they restrict air flow greatly compared to the surrounding environment.
Not that it's a measurable factor to our sensors, but not only, compressed air heats, not cools.

I believe the thinking with Venturi is that as a mass of air enters a constriction (inner chamber of shield in this instance), the pressure actually drops as it elongates. And I guess people are assuming that a drop in pressure corresponds to a drop in temperature? If this is true, then someone needs to explain why air expands as it warms and drops in pressure (unless constrained on all sides like in a pressure cooker).

I think you are confusing pressure and density.  As air warms in the open atmosphere its pressure remains the same but it decreases in density and thus expands.  If you warm air in a pressure cooker air will try to expand and take up more volume as the temperatures rise. However since it is constrained like you said its pressure rises proportionally to temperature.

In theory a venturi tube works like this.  As air flows though a narrower section of pipe its velocity increases and as a result its static pressure.  As a result of this pressure decrease you should get a drop in temperature where the pipe narrows.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 14, 2018, 09:47:07 PM
Looks like other shields got dinged for running cooler also.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: jgentry on August 14, 2018, 10:08:03 PM
Looks like other shields got dinged for running cooler also.

According to that study, the author thinks the Davis passive is better than the Davis FARS...
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: hwcorder on August 14, 2018, 10:58:02 PM
Looks like I'm may have to buy an extra transmitter and start running my own shield to shield comparisons.  Whats another 100 dollars I guess. I feel like with all the money I've put into my VP2 I could have been half way to my own ASOS by now.  :lol:
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 14, 2018, 11:02:10 PM
Looks like other shields got dinged for running cooler also.

According to that study, the author thinks the Davis passive is better than the Davis FARS...

Followed the reference 97-99% of time depending on wind speed is why. 
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: openvista on August 14, 2018, 11:35:57 PM
About the Venturi Effect...

The main point is that if this effect were present during the day, it would be also be present at night since this is a 24hr FARS. Yet we know that, for the most part (with certain exceptions during limited time periods) the temperature measurements from all the shields converge at night.

Not saying the effect isn't real. It's all about where it's happening (at the intake) and whether the effect is negligible or not present at the measurement location. It's probably extremely local and small.

Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: openvista on August 15, 2018, 02:58:54 AM
Looks like other shields got dinged for running cooler also.

In fact, every other ventilated shield was found "disappointing" except the reference Eigenbrodt shield. Hmmm....

That includes the R.M. Young 43502 which has long been considered a reference shield in its own right. Someone should ask kcidwx if he's ever noticed it running warm when winds are 7+ mph (3 m/s) since that's his main shield.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 15, 2018, 05:42:49 AM

My main focus has been primarily on daytime performance but looking at nightime you can see the 7714 doesn't perform as well as the BARANI DESIGN Helix shields. They may come together around sunrise still couple hours away still but the passive 7714 has lagged all night.  [ You are not allowed to view attachments ]
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 15, 2018, 08:00:23 AM
I looked at data logger from yesterday and these were the recorded highs. So .7 between the 7714 and Pro.
Made correction.

PRO-        79.6
Standard- 80.6
7714-       78.9
FARS-       78.5

Lows today

Pro-          55.6
Standard- 55.5
7714-       56.1
FARS-      55.7
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: Bobvelle on August 15, 2018, 08:20:30 AM
This is my Davis FARS vs Meteoshield standard temp graph for yesterday. They are mounted about a foot apart and both housing a SHT31 sensor w/sensirion filter. Not real impressed, although I'm not surprised as I get very little wind here.

FARS= Blue
Meteo= Orange

afternoon wind ~ 1.5 mph

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Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 15, 2018, 08:46:20 AM
I made a correction on yesterday's numbers. Doesn't look as good.
Thanks for sharing Bobvelle. Yes I really at this point can't recommend the standard without additional shielding. Jerry's been working on that.  :idea:
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 15, 2018, 09:30:26 AM
I've decided to stop testing on standard shield.
I see no reason to continue, it reminds me of the Davis Pro shield. Once any shield gets in the +2 range and looking at Bobville graph confirms not interested.

I've asked for a return RMA#.
Still interested in pro shield so not completely done testing.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: Bobvelle on August 15, 2018, 10:33:55 AM
Well before we 'throw out the baby with the bath water'. Let me clarify some things.

1. The location of the FARS shield IS partially covered by the 30w PV panel above it during the noon hours and the Meteoshield is fully exposed.

2. I'm not sure if it matters..(and it shouldn't ) but I realized this morning that the SHT31 in the Meteoshield is mounted with the sensor facing south, fully exposed to the southern facing gills. It is perfectly centered horizontally and vertically in the shield cavity. Mounted with 3/4" standoffs to a narrow piece of black Kydex I molded into a bracket that attaches to the Meteo's bracket/base. ( I'll try to get a photo today)

I will, this afternoon, attempt to move the FARS 180 degrees opposing (on a east/west axis) the Meteo shield. This way insuring they get simultaneous and equal sun exposure. I will also turn the sensor to face a neutral position like Northeast, but other than due south. (this was purely coincidental   #-o).

After which, I will post another day's results. Honestly, I'm not expecting MUCH improvement, but at least it will be a more honest comparison.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: Bobvelle on August 15, 2018, 11:53:12 AM
Interesting also..
Humidity difference between FARS and Meteoshield. Again, both with SHT31s. Consistently lower RH with the Meteo during solar heating hours. And, Again the crossover @ approx 8pm. Maybe the night radiation effect (or what ever it's called)?
FARS= Purple
Meteo= Black

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Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: dendrite on August 15, 2018, 11:57:34 AM
If the Pro is reading a warmer temp during the day then the RH should be lower since it's temp dependent. It was cooler at night too so the higher RH then makes sense as well. Do you have a graph of the dewpoints? I assume they're running neck and neck.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: Bobvelle on August 15, 2018, 12:06:01 PM
If the Pro is reading a warmer temp during the day then the RH should be lower since it's temp dependent. It was cooler at night too so the higher RH then makes sense as well. Do you have a graph of the dewpoints? I assume they're running neck and neck.

Unfortunately no, I only have a DP graph for the primary (FARS) sensor. I am limited with my equipment.

But when you say "the Pro" do you mean the Davis Pro 2 or the Meteoshield Pro?  Because I only have the Meteo Standard shield not the Pro version. And it was running higher temps but lower RH, which would correlate with your comment.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: Bobvelle on August 15, 2018, 12:10:43 PM
This is both, and basically confirms what you stated.
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OK.. I'm done posting graphs now..  :grin:
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: Bobvelle on August 15, 2018, 12:34:42 PM
I made a correction on yesterday's numbers. Doesn't look as good.
Thanks for sharing Bobvelle. Yes I really at this point can't recommend the standard without additional shielding. Jerry's been working on that.  :idea:

I don't have a Meteoshield Pro, so I don't know (Ha  :-P).. But what is it about the design/construction of the Meteoshield Pro, In your opinion, that would make it a 'better' radiation shield than the standard version shield?
I know it's a smaller, narrower cavity and more louvers/gills, but is that the only difference?
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: dendrite on August 15, 2018, 12:38:46 PM
If the Pro is reading a warmer temp during the day then the RH should be lower since it's temp dependent. It was cooler at night too so the higher RH then makes sense as well. Do you have a graph of the dewpoints? I assume they're running neck and neck.

Unfortunately no, I only have a DP graph for the primary (FARS) sensor. I am limited with my equipment.

But when you say "the Pro" do you mean the Davis Pro 2 or the Meteoshield Pro?  Because I only have the Meteo Standard shield not the Pro version. And it was running higher temps but lower RH, which would correlate with your comment.
Sorry. I meant Meteoshield...thought you had the Pro version.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: Bobvelle on August 15, 2018, 12:48:19 PM
If the Pro is reading a warmer temp during the day then the RH should be lower since it's temp dependent. It was cooler at night too so the higher RH then makes sense as well. Do you have a graph of the dewpoints? I assume they're running neck and neck.

Unfortunately no, I only have a DP graph for the primary (FARS) sensor. I am limited with my equipment.

But when you say "the Pro" do you mean the Davis Pro 2 or the Meteoshield Pro?  Because I only have the Meteo Standard shield not the Pro version. And it was running higher temps but lower RH, which would correlate with your comment.
Sorry. I meant Meteoshield...thought you had the Pro version.

I might get the Pro version... but I will probably need the money back for the Standard before I make that leap. And I may wait for more consensus on its performance before that too.

Although, honestly, I like my FARS setup. It's nothing like Davis's original design, with a larger AGM battery, 30w panel and faster, more reliable fan, it works perfectly. Not really looking to replace it anyway.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 15, 2018, 12:49:28 PM
I made a correction on yesterday's numbers. Doesn't look as good.
Thanks for sharing Bobvelle. Yes I really at this point can't recommend the standard without additional shielding. Jerry's been working on that.  :idea:

I don't have a Meteoshield Pro, so I don't know (Ha  :-P).. But what is it about the design/construction of the Meteoshield Pro, In your opinion, that would make it a 'better' radiation shield than the standard version shield?
I know it's a smaller, narrower cavity and more louvers/gills, but is that the only difference?

The pro is larger overall and has double helical internal shield of all black design. One thing I give praise for is rapid response compared to the 7714.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 15, 2018, 02:04:39 PM
Another positive I see is humidity does seem to run higher during rain and temperature slightly lower than even fars.  The 7714 was lagging about .4F and finally caught up with Fars after about 30 minutes. 
The rapid response to changes may actually be part of shields running higher vs 7714. The 7714 really does lag behind so I suspect it doesn't measure as accurately either high or low side.

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Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 15, 2018, 05:25:47 PM
One guess.
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Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: Bobvelle on August 15, 2018, 05:35:00 PM
That's some kind of bucket lid?

I used the lid of a 5 gal bucket as a Day FARS hanger a couple years ago. Worked pretty well.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: openvista on August 15, 2018, 05:48:09 PM
Today was partly sunny here with a thin layer of clouds even when the sun shone. But we did get to the point where shadows were clearly visible for a couple hours - see data below. Not a perfect day for testing by any means but still meaningful.

As stated previously, I'm running the 7714 at 20ft and the 7755 FARS at 5ft. The test is mainly to see if there was an improvement from when the shield was near ground level (<4ft on my rain gauge post) in a sheltered location.

I can say absolutely there's been an improvement. I never saw agreement like this before. Even my wife noticed the difference which is hard to miss when you're accustomed to 2-4F differences during the daytime. I don't think I even saw a 1F departure at any time today.

It's all about the air flow!

Here are the average temperatures from 3PM - 5PM (avg wind: 2.3mph at 28ft):
FARS: 69.53F
7714: 69.85F

Difference: +0.31F (7714 warmer)

That's within the spec of the sensor so I would say they are even at this point.

For those curious about overnight differences, there were none. The lows were within 0.3F of each other (7714 slightly cooler); It was a cloudy night with very light breezes.

Looks like Friday is our first shot at decent sunshine. I'll report back then.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: dendrite on August 15, 2018, 05:57:35 PM
I'll be interested to see the differences on a radiational cooling night. You're still running all 31s, correct?
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 15, 2018, 06:02:15 PM
That's some kind of bucket lid?

I used the lid of a 5 gal bucket as a Day FARS hanger a couple years ago. Worked pretty well.

Jerry has been testing for a few days over the Pro and says amazing results very close to FARS.
It's a old food dehydrator lid I had in storage with a spare bracket Scaled Instruments sells for mounting shields.

Any sturdy plastic 14" diameter or so can be used and yes it will reduce the overhead solar exposure.
Jerry noticed some high end shields were using something similar above there shields but asking $750 for the units..LOL
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 15, 2018, 06:03:21 PM
I'll be interested to see the differences on a radiational cooling night. You're still running all 31s, correct?

Yes still all 31's. Don't want to mix sensors right now these 31's are all within .1 of each other.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 15, 2018, 06:06:50 PM
Today was partly sunny here with a thin layer of clouds even when the sun shone. But we did get to the point where shadows were clearly visible for a couple hours - see data below. Not a perfect day for testing by any means but still meaningful.

As stated previously, I'm running the 7714 at 20ft and the 7755 FARS at 5ft. The test is mainly to see if there was an improvement from when the shield was near ground level (<4ft on my rain gauge post) in a sheltered location.

I can say absolutely there's been an improvement. I never saw agreement like this before. Even my wife noticed the difference which is hard to miss when you're accustomed to 2-4F differences during the daytime. I don't think I even saw a 1F departure at any time today.

It's all about the air flow!

Here are the average temperatures from 3PM - 5PM (avg wind: 2.3mph at 28ft):
FARS: 69.53F
7714: 69.85F

Difference: +0.31F (7714 warmer)

That's within the spec of the sensor so I would say they are even at this point.

For those curious about overnight differences, there were none. The lows were within 0.3F of each other (7714 slightly cooler); It was a cloudy night with very light breezes.

Looks like Friday is our first shot at decent sunshine. I'll report back then.

Very good test.. =D&gt;
I must have better air movement my lot is rather large.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: dendrite on August 15, 2018, 06:18:23 PM
I'll be interested to see the differences on a radiational cooling night. You're still running all 31s, correct?

Yes still all 31's. Don't want to mix sensors right now these 31's are all within .1 of each other.
Sorry...that was meant for openvista.

I know you had all of your sensors reading the same before your tests, but have you considered shifting the sensors into other shields?
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 15, 2018, 06:28:23 PM
I'll be interested to see the differences on a radiational cooling night. You're still running all 31s, correct?

Yes still all 31's. Don't want to mix sensors right now these 31's are all within .1 of each other.
Sorry...that was meant for openvista.

I know you had all of your sensors reading the same before your tests, but have you considered shifting the sensors into other shields?

No I've done these test before every 31 is the same with temperature unlike the others like 15 and 11 you could get a few tenths difference.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 15, 2018, 06:38:17 PM
The new look.
I know this screws the test up somewhat but I think I know how it would of went and like the fast response rate I see similar to fars unlike many passive units.
If all it takes is a top plate, plus maybe the standard version would work with something like this and everyone save a few $ over the pro.   
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: openvista on August 15, 2018, 06:38:47 PM
I'll be interested to see the differences on a radiational cooling night. You're still running all 31s, correct?

Yes, both shields contain SHT31 sensors. They both test well within temp specs on my traceable PRT.

Looks like either Thu night or Fri night might qualify for radiational cooling: partly cloudy to clear with low winds.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: CW2274 on August 15, 2018, 06:53:57 PM
It's all about the air flow!
:shock:


:-P
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: Bobvelle on August 15, 2018, 07:24:13 PM
The new look.
I know this screws the test up somewhat but I think I know how it would of went and like the fast response rate I see similar to fars unlike many passive units.
If all it takes is a top plate, plus maybe the standard version would work with something like this and everyone save a few $ over the pro.

I've been meaning to ask... WHAT'S UP WITH THOSE YELLOW ZIP-TIES :!: :?:  Are they some kind of bird spikes?

Sorry. just a little OCD about uncut zip-ties  :grin:
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: Bobvelle on August 15, 2018, 07:35:18 PM
Oh as promised

Sensor bracket (facing NE now)
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Opposed on E-W axis for even exposure now.
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Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: CW7491 on August 15, 2018, 07:46:12 PM
Randy, thank you for investing the time, money and effort to conduct these comparisons and then posting them for all of our benefit. Seeing your updates is like watching the next episode of my favorite series ...

If you dont get the results youre looking for in the passive shields, one thing you may want to consider if you think itd be worth the effort is a little more separation between the shields to avoid one influencing the other and to promote airflow. When I did the side by side with the Davis FARS and the 7714, I initially had it set up as you do. I ended up getting better results with more separation (whether it was fan exhaust or airflow/solar shading I dont know.) Not to say youd get the same results, but just throwing it out there.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 15, 2018, 07:53:19 PM
The new look.
I know this screws the test up somewhat but I think I know how it would of went and like the fast response rate I see similar to fars unlike many passive units.
If all it takes is a top plate, plus maybe the standard version would work with something like this and everyone save a few $ over the pro.

I've been meaning to ask... WHAT'S UP WITH THOSE YELLOW ZIP-TIES :!: :?:  Are they some kind of bird spikes?

Sorry. just a little OCD about uncut zip-ties  :grin:

Yep they are my bird spikes they were landing on my solar sensor. Once I but the rainbucket on it stopped. I have it off for now I don't use the Davis rain bucket.
Randy, thank you for investing the time, money and effort to conduct these comparisons and then posting them for all of our benefit. Seeing your updates is like watching the next episode of my favorite series ...

If you dont get the results youre looking for in the passive shields, one thing you may want to consider if you think itd be worth the effort is a little more separation between the shields to avoid one influencing the other and to promote airflow. When I did the side by side with the Davis FARS and the 7714, I initially had it set up as you do. I ended up getting better results with more separation (whether it was fan exhaust or airflow/solar shading I dont know.) Not to say youd get the same results, but just throwing it out there.

Your welcome,
Yes thought about separation too. These short sensor wires are causing issues.
After removing the standard shield I have better separation except from the Davis transmitters.  :sad:
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 15, 2018, 11:24:01 PM
Today was rainy with 1.71" total spread out couple times during day. A few things I noticed was the 7714 does lag with the pro having quicker temperature changes. Even prior to rain last night the 7714 was behind about .5f.
Tonight the Pro has reached 98% humidity before 10pm which is max on sensor. The Fars 97% and 7714 96%.
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Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: jgentry on August 16, 2018, 12:34:47 AM
Today was rainy with 1.71" total spread out couple times during day. A few things I noticed was the 7714 does lag with the pro having quicker temperature changes. Even prior to rain last night the 7714 was behind about .5f.
Tonight the Pro has reached 98% humidity before 10pm which is max on sensor. The Fars 97% and 7714 96%.
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Let us know how high the humidity reaches too in the pro compared to the other shields in the morning. Im liking what Im hearing so far.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 16, 2018, 06:36:40 AM
Today was rainy with 1.71" total spread out couple times during day. A few things I noticed was the 7714 does lag with the pro having quicker temperature changes. Even prior to rain last night the 7714 was behind about .5f.
Tonight the Pro has reached 98% humidity before 10pm which is max on sensor. The Fars 97% and 7714 96%.
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Let us know how high the humidity reaches too in the pro compared to the other shields in the morning. Im liking what Im hearing so far.

Well surprised me the pro has been 99% since around midnight when sensor before peaked at 98%, the Fars 98% and 7714 has old sensor can only reach 96%. Looks like the pro has squeezed additional 1% if that's possible? But even fog before all I saw was 98% max and no fog today.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: dendrite on August 16, 2018, 09:26:10 AM
I find mine has to hit 98% early in the evening to have a chance at 99% or 100%. You've done a lot of reconditioning on the sensors recently so I'd be hesitant to make any assumptions on max potential RH between the different shields unless you swap some of the sensors around. Maybe just switch the FARS and Pro ones and see if the same thing happens again overnight after another wet day.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 16, 2018, 11:04:11 AM
I find mine has to hit 98% early in the evening to have a chance at 99% or 100%. You've done a lot of reconditioning on the sensors recently so I'd be hesitant to make any assumptions on max potential RH between the different shields unless you swap some of the sensors around. Maybe just switch the FARS and Pro ones and see if the same thing happens again overnight after another wet day.

The Pro has never been reconditioned. I'm not really concerned about RH at this time was just answering a question. They would of all went to 100% I'm sure no problem last night had the sensors been capable. Everything was dripping wet after all the rain and cool temps down to 51, amazing fog didn't develop.

I'm also finding no real improvement after reconditioning at least on top end. I just did a sensor that would only reach 95% and no change whatsoever on top end. I really don't remember what it did new, at least 97%.  This was one of my oldest sensors installed at remote site when the 31's first came out so at least 2 years in service.  Still usable but max 95% probably only around the home monitors. Freezer, garage, patio etc.   

Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 16, 2018, 01:19:31 PM
Beautiful sunny day almost zero wind at sensor level, should be the ultimate test day for what to expect in worse conditions for passive shield, no wind and sunny.   
I did put the standard back up so all can see the performance and do have top shields over both Meteo. Not sure it really does much but why not.

I'll post graphs with wind speeds and solar information after peak temperatures later today. Test officially started at 12 noon Central so all shields were dry from the rain and none had any advantage.

Preview of current condition snapshot. Have no idea myself so will look later. 

Be back later after peak temperatures, later.
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Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: jgentry on August 16, 2018, 02:24:52 PM
Beautiful sunny day almost zero wind at sensor level, should be the ultimate test day for what to expect in worse conditions for passive shield, no wind and sunny.   
I did put the standard back up so all can see the performance and do have top shields over both Meteo. Not sure it really does much but why not.

I'll post graphs with wind speeds and solar information after peak temperatures later today. Test officially started at 12 noon Central so all shields were dry from the rain and none had any advantage.

Preview of current condition snapshot. Have no idea myself so will look later. 

Be back later after peak temperatures, later.
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The pro shield looks good. FARS might be reading slightly cooler due to its design?  Davis passive either looks good because its good or there is lagging involved. If I were Barani, I would do away with the standard shield and just sell the pro.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: CW2274 on August 16, 2018, 03:35:55 PM
Beautiful sunny day almost zero wind at sensor level, should be the ultimate test day for what to expect in worse conditions for passive shield, no wind and sunny.   
I did put the standard back up so all can see the performance and do have top shields over both Meteo. Not sure it really does much but why not.

I'll post graphs with wind speeds and solar information after peak temperatures later today. Test officially started at 12 noon Central so all shields were dry from the rain and none had any advantage.

Preview of current condition snapshot. Have no idea myself so will look later. 

Be back later after peak temperatures, later.
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 FARS might be reading slightly cooler due to its design? 
Well, that's the rub. Some say it's because FARS makes the temp artificially low (which I think is a load of crap because of some of the ridiculous data), or it's low because it better at it's job.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 16, 2018, 04:21:07 PM
Beautiful sunny day almost zero wind at sensor level, should be the ultimate test day for what to expect in worse conditions for passive shield, no wind and sunny.   
I did put the standard back up so all can see the performance and do have top shields over both Meteo. Not sure it really does much but why not.

I'll post graphs with wind speeds and solar information after peak temperatures later today. Test officially started at 12 noon Central so all shields were dry from the rain and none had any advantage.

Preview of current condition snapshot. Have no idea myself so will look later. 

Be back later after peak temperatures, later.
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The pro shield looks good. FARS might be reading slightly cooler due to its design?  Davis passive either looks good because its good or there is lagging involved. If I were Barani, I would do away with the standard shield and just sell the pro.

Think you'll like the test results on pro. Once again the rapid response to temperature change is really good. Just had first cloud which doesn't mess test up because we went through highest solar period cloud free with no wind.
Running almost a full degree under the lagging 7714. Still not low as  fars but for wind free day not bad.
   

Peek
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Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: jgentry on August 16, 2018, 04:39:20 PM
Beautiful sunny day almost zero wind at sensor level, should be the ultimate test day for what to expect in worse conditions for passive shield, no wind and sunny.   
I did put the standard back up so all can see the performance and do have top shields over both Meteo. Not sure it really does much but why not.

I'll post graphs with wind speeds and solar information after peak temperatures later today. Test officially started at 12 noon Central so all shields were dry from the rain and none had any advantage.

Preview of current condition snapshot. Have no idea myself so will look later. 

Be back later after peak temperatures, later.
 [ You are not allowed to view attachments ]

The pro shield looks good. FARS might be reading slightly cooler due to its design?  Davis passive either looks good because its good or there is lagging involved. If I were Barani, I would do away with the standard shield and just sell the pro.

Think you'll like the test results on pro. Once again the rapid response to temperature change is really good. Just had first cloud which doesn't mess test up because we went through highest solar period cloud free with no wind.
Running almost a full degree under the lagging 7714. Still not low as  fars but for wind free day not bad.
   

Peek
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Just basing off the WMO study on Davis FARS, the results on Pro looks awesome! Im just assuming that the FARS is off on the cool side by the way.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: dendrite on August 16, 2018, 04:55:05 PM
Beautiful sunny day almost zero wind at sensor level, should be the ultimate test day for what to expect in worse conditions for passive shield, no wind and sunny.   
I did put the standard back up so all can see the performance and do have top shields over both Meteo. Not sure it really does much but why not.

I'll post graphs with wind speeds and solar information after peak temperatures later today. Test officially started at 12 noon Central so all shields were dry from the rain and none had any advantage.

Preview of current condition snapshot. Have no idea myself so will look later. 

Be back later after peak temperatures, later.
 [ You are not allowed to view attachments ]

 FARS might be reading slightly cooler due to its design? 
Well, that's the rub. Some say it's because FARS makes the temp artificially low (which I think is a load of crap because of some of the ridiculous data), or it's low because it better at it's job.
I dont buy it either. Often when my 2m temp rots at 32F following a weak, overrunning FZRA system, my sensor continuously fluctuates between 31.9 and 32.1. Thats what you would expect with no temperature advection while hovering at a phase change.

If venturi had an effect, it would be colder at night as well. Theres a reason why ASOS is strongly aspirated. The fewer the moving parts the more they like it.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: jerryg on August 16, 2018, 05:23:12 PM
I think it shows that the pro is a good shield and can work well in place of the Davis fars. I have been using the pro for some time now and am getting good results compared to the fars which i still have running. Just to show you my high temperature recorded by the fars at 2.23pm was 97.5F degrees and the pro at the same time showed 96.9F degrees. Just love it.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: CW2274 on August 16, 2018, 05:48:59 PM
Just to show you my high temperature recorded by the fars at 2.23pm was 97.5F degrees and the pro at the same time showed 96.9F degrees. Just love it.
Not that the Pro isn't stepping up to the plate, but as I stated before, I still think the FARS can be higher just for the simple fact it's always pulling air across the sensor and catching the higher temp the passive may be missing. Of course, that's just my theory.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: dendrite on August 16, 2018, 05:58:15 PM
Just to show you my high temperature recorded by the fars at 2.23pm was 97.5F degrees and the pro at the same time showed 96.9F degrees. Just love it.
Not that the Pro isn't stepping up to the plate, but as I stated before, I still think the FARS can be higher just for the simple fact it's always pulling air across the sensor and catching the higher temp the passive may be missing. Of course, that's just my theory.
Im losing track of everyones setups, but he has just the stock fan too, correct?
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: jerryg on August 16, 2018, 06:05:30 PM
That could be true but the wind was blowing real well so the passive was getting a good air flow and the pro with it's spiral design helps mix the air real well. I think the design of the pro is making a difference compared to standard passive shields. I think it will take a while to really get a good feel for the pro because of the different design elements. I like not having to mess with a fan and power source and if the shield lives up to the cleaner shield and sensor it is really a plus. I live in the country and am surrounded by farm lands and with all the plowing and harvesting and spraying of crops i need all the help i can get. I have brought the fars in and after taking it apart the inside was almost black with dust and the filter was almost clogged up on the intake side of the filter. So if i can get some relief from the cleaning chores and not have to mess with fans and power i am sold completely on the pro until it lets me down lol.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: jerryg on August 16, 2018, 06:07:34 PM
If you are asking me yes the fars is a stock davis set up other than i am running the fan off of a walwart at 2.3 volts during the day and 1 volt at night using a photocell and relay setup.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: CW2274 on August 16, 2018, 06:08:40 PM
Just as a further thought, this is exactly why ASOS's use an averaging algorithm, to eliminate the high and low spikes that we aspirated PWS folks take for granted.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: CW2274 on August 16, 2018, 06:14:47 PM
So if i can get some relief from the cleaning chores and not have to mess with fans and power i am sold completely on the pro until it lets me down lol.
Absolutely! I deal with a filthy sensor chamber too, but not enough for me to abandon my fan. If I didn't already have my current setup well established, I might have actually tried this.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: jerryg on August 16, 2018, 06:18:10 PM
I'm sure at any given time the readings can be one way or the other that is why the most important reading to me is the min/max of the day so all the up and downs of the day can be ignored as far as i am concerned.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: dendrite on August 16, 2018, 06:21:05 PM
Just as a further thought, this is exactly why ASOS's use an averaging algorithm, to eliminate the high and low spikes that we aspirated PWS folks take for granted.
I think the 5-min running averages best mimicked Hg thermometers. So when these stations went from max/min liquid-filled thermometers to aspirated probes they needed the averaging to maintain consistency with the climo record.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: CW2274 on August 16, 2018, 06:30:51 PM
I'm sure all of us have seen our temp go up a degree or whatever for a packet cycle, then never to be seen again, that's our high. An ASOS would never report such a thing as valid, only as a number to be averaged in it's determined cycle.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: dendrite on August 16, 2018, 06:41:45 PM
I'm sure all of us have seen our temp go up a degree or whatever for a packet cycle, then never to be seen again, that's our high. An ASOS would never report such a thing as valid, only as a number to be averaged in it's determined cycle.
Good stuff here...

https://training.weather.gov/nwstc/DATAACQ/d.ASOShuman/Temp.htm
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: jerryg on August 16, 2018, 06:45:33 PM
I am sure that for official records and stuff that some kind of averaging is needed but for us pws owners and our fans  :lol: most asked what was the high or low temp for the day, not caring about averages etc. Most people don't care about the little up and downs of the day.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: CW2274 on August 16, 2018, 07:09:07 PM
I'm sure all of us have seen our temp go up a degree or whatever for a packet cycle, then never to be seen again, that's our high. An ASOS would never report such a thing as valid, only as a number to be averaged in it's determined cycle.
Good stuff here...

https://training.weather.gov/nwstc/DATAACQ/d.ASOShuman/Temp.htm
Indeed, read the whole thing. I certainly remember the HO-83 fiasco here in the early nineties, even the Chamber of Commerce got involved.
Makes me love my well aspirated PWS even more.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: hwcorder on August 16, 2018, 07:24:44 PM
I'm sure all of us have seen our temp go up a degree or whatever for a packet cycle, then never to be seen again, that's our high. An ASOS would never report such a thing as valid, only as a number to be averaged in it's determined cycle.
Good stuff here...

https://training.weather.gov/nwstc/DATAACQ/d.ASOShuman/Temp.htm
Indeed, read the whole thing. I certainly remember the HO-83 fiasco here in the early nineties, even the Chamber of Commerce got involved.
Makes me love my well aspirated PWS even more.

If I remember correctly it wasnt due to lack of aspiration the problem more associated with exhaust air being recirculated back through the HO-83.  Air being deflected down from the top rounded dome at the top of the shield was then getting sucked back into the intake at the bottom.  Every time this happened the air was warmed little by little.  This is why they added the fin towards the bottom of the shield to deflect air to the side preventing recirculation.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: Bobvelle on August 16, 2018, 07:31:48 PM
If you are asking me yes the fars is a stock davis set up other than i am running the fan off of a walwart at 2.3 volts during the day and 1 volt at night using a photocell and relay setup.

What are you using after the relay switches to reduce the voltage? I tried doing this with a 20ohm resistor but that resistor was getting way too hot. Trying to find something I have laying around instead having to buy a voltage regulator.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: CW2274 on August 16, 2018, 07:39:33 PM
I'm sure all of us have seen our temp go up a degree or whatever for a packet cycle, then never to be seen again, that's our high. An ASOS would never report such a thing as valid, only as a number to be averaged in it's determined cycle.
Good stuff here...

https://training.weather.gov/nwstc/DATAACQ/d.ASOShuman/Temp.htm
Indeed, read the whole thing. I certainly remember the HO-83 fiasco here in the early nineties, even the Chamber of Commerce got involved.
Makes me love my well aspirated PWS even more.

If I remember correctly it wasnt due to lack of aspiration the problem more associated with exhaust air being recirculated back through the HO-83.  Air being deflected down from the top rounded dome at the top of the shield was then getting sucked back into the intake at the bottom.  Every time this happened the air was warmed little by little.  This is why they added the fin towards the bottom of the shield to deflect air to the side preventing recirculation.
Took me awhile to find...here ya go.
https://journals.ametsoc.org/doi/pdf/10.1175/1520-0442%281992%29005%3C0657%3ATRMTAI%3E2.0.CO%3B2
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: openvista on August 16, 2018, 07:43:13 PM
The WMO study came to the opposite conclusion of every other shield comparison I've ever read (and I've read plenty of 'em). Therefore, many more studies finding aspirated shields are "disappointing" compared to passive shields in high insolation, low wind situations are necessary before I'd buy in.

But that won't keep me from running as honest a test as I can between the 7714 and FARS.

Seems to me that it would be well enough to find a passive shield running even with the FARS, which is, apparently, what we are seeing with the Meteoshield Pro and to a lesser extent, the 7714. 

Tomorrow I get Randy's weather and will put the 7714 through its paces.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: Bobvelle on August 16, 2018, 07:43:28 PM
So here is today after making the changes to even out exposure. Pretty much the same thing. +2 deg avg. afternoon sun with the Meteo Standard..

SHT31 Meteoshield standard
SHT31 Davis FARS

Afternoon Wind ~1.5 mph

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Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: CW2274 on August 16, 2018, 07:45:38 PM
If you are asking me yes the fars is a stock davis set up other than i am running the fan off of a walwart at 2.3 volts during the day and 1 volt at night using a photocell and relay setup.

What are you using after the relay switches to reduce the voltage?
Just me, but I still think this is a complete waste of time. Let'er rip.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 16, 2018, 07:45:51 PM
Well great test day with wind speed very low 0 mph much of day, sunny except maybe 2 clouds all day.

This is what can be expected on worse day passive vs FARS.
Both Meteoshields have additional top shield. I'm little skeptical of how well it helps at this latitude but it did provide partial shade most of day. That of course ends as we go into winter and top cover does little shading. As stated several times the Meteoshields have good response for passive they really leave the 7714 in the dust.
 
I can't recommend the Standard even at price point. Not horrible but I would spend money on the better 7714 before the standard.

The PRO is better than the 7714 imo so plan on adding second unit if they take the standard shield back. Still no response from them on returning. Maybe they didn't like what I said about it.  Just it didn't meet my expectations...What's wrong with that? :lol:

Anyone getting one of these shields I recommend the 30' sensor just because the Davis plugs are so short. I do think Jerry said he got one working with stock setup but not 100% on that. 
You will need to cut down the sensor to fit inside the Pro shield. I just used tin snips. For filter I used low VOC glue and just glued on using one corner of Davis filter. The glue I used easily pulls off later for changing. One stock Davis filter gives 4 filter changes.
 
Broke down FARS against each shield for cleaner comparision

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Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: CW2274 on August 16, 2018, 08:00:25 PM
Therefore, many more studies finding aspirated shields are "disappointing" compared to passive shields in high insolation, low wind situations are necessary before I'd buy in.
+1   There's not enough convoluted evidence on this planet that could convince me that a passive shield would out perform an aspirated shield in my climate when your skin will burn in literal minutes and the wind is calm.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: CW2274 on August 16, 2018, 08:04:56 PM
Well great test day with wind speed very low 0 mph much of day, sunny except maybe 2 clouds all day.

This is what can be expected on worse day passive vs FARS.
Both Meteoshields have additional top shield. I'm little skeptical of how well it helps at this latitude but it did provide partial shade most of day. That of course ends as we go into winter and top cover does little shading. As stated several times the Meteoshields have good response for fars they really leave the 7714 in the dust.
 
I can't recommend the Standard even at price point. Not horrible but I would spend money on the better 7714 before the standard.

The PRO is better than the 7714 imo so plan on adding second unit if they take the standard shield back. Still no response from them on returning. Maybe they didn't like what I said about it.  Just it didn't meet my expectations...What's wrong with that? :lol:

Anyone getting one of these shields I recommend the 30' sensor just because the Davis plugs are so short. I do think Jerry said he got one working with stock setup but not 100% on that. 
You will need to cut down the sensor to fit inside the Pro shield. I just used tin snips. For filter I used low VOC glue and just glued on using one corner of Davis filter. The glue I used easily pulls off later for changing. One stock Davis filter gives 4 filter changes.
 
Broke down FARS against each shield for cleaner comparision

As always Randy.... =D&gt;
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: openvista on August 16, 2018, 08:08:10 PM
By the way, I have an idea for a pole mounting solution for the VP2 SIM (removing it from the rain base completely) if anyone needs it.

I'm going to take a piece of 12" x 12" x 0.5" acrylic (https://www.amazon.com/gp/product/B00C13Z6UI/ref=od_aui_detailpages00?ie=UTF8&psc=1), cut it to size and route out a hole for the clip so it rests flush.

Then drill a hole in the upper right and lower left of the housing, thread through a couple 1/4" bolts with washers and lock nuts on other side.

Because the clip on the rear is 3/4" deep and the acrylic is only 1/2" thick, you can't mount the u-bolt above the SIM and or clip will go through the hole, hitting the pole and preventing the SIM from sitting flush against the acrylic. So I plan to mount the u-bolt beside the SIM (which is 5" wide, 6.5" long). 3/4" thick acrylic was more than 3x the price!

Also, there are a couple 1/4" deep bump outs on the right side that can be balanced with an extra nut and washer on the left side (between the SIM and acrylic) or a proper 1/4" standoff if you have one.

I thought about using a J-bolt against the clip, but then you could only balance that with one bolt in the upper right (and a 3/4" standoff). The left side would just hang there because there's not enough space in the upper left or center top for a bolt. The wind could flex it over time and weaken the plastic around the other bolts.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: openvista on August 16, 2018, 08:13:12 PM
Well great test day with wind speed very low 0 mph much of day, sunny except maybe 2 clouds all day.

This is what can be expected on worse day passive vs FARS.
Both Meteoshields have additional top shield. I'm little skeptical of how well it helps at this latitude but it did provide partial shade most of day. That of course ends as we go into winter and top cover does little shading. As stated several times the Meteoshields have good response for fars they really leave the 7714 in the dust.
 
I can't recommend the Standard even at price point. Not horrible but I would spend money on the better 7714 before the standard.

The PRO is better than the 7714 imo so plan on adding second unit if they take the standard shield back. Still no response from them on returning. Maybe they didn't like what I said about it.  Just it didn't meet my expectations...What's wrong with that? :lol:

Anyone getting one of these shields I recommend the 30' sensor just because the Davis plugs are so short. I do think Jerry said he got one working with stock setup but not 100% on that. 
You will need to cut down the sensor to fit inside the Pro shield. I just used tin snips. For filter I used low VOC glue and just glued on using one corner of Davis filter. The glue I used easily pulls off later for changing. One stock Davis filter gives 4 filter changes.
 
Broke down FARS against each shield for cleaner comparision

As always Randy.... =D&gt;

Yes, Randy, thank you for the data!
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: jerryg on August 16, 2018, 08:18:34 PM
I to tried resistors but way too much variations in voltage so i just used the drop across a silcon diode at .7 volts. I had a 3 volt wallwart and put 3 diode in series which gave me a volt for night time use and the relay at night is basically not in use then in the am the photocell pulls the relay closed and i use a set of normal open contacts that close when the relay pulls and shorts out 2 of the diodes of the 3 that are in series which gives me just one diode for a voltage of 2.3 volts for daytime running.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: jerryg on August 16, 2018, 08:26:18 PM
I think everyone needs to remember that the location that i am at is great for the pro and some locations like the desert southwest may need the fars. In my location wind is not a problem, it blows most of the time and i don't have extreme heat or cold and my main concern is the high humidity at night that we have nearly year round and the effect it has on the Davis sensors. Everything is a trade off of some kind, i would think in the hot s.w. region that the more air the better. I am fortunate that mother nature supplies me with an abundance of moving air lol.












Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: Bobvelle on August 16, 2018, 08:54:47 PM
I to tried resistors but way too much variations in voltage so i just used the drop across a silcon diode at .7 volts. I had a 3 volt wallwart and put 3 diode in series which gave me a volt for night time use and the relay at night is basically not in use then in the am the photocell pulls the relay closed and i use a set of normal open contacts that close when the relay pulls and shorts out 2 of the diodes of the 3 that are in series which gives me just one diode for a voltage of 2.3 volts for daytime running.

HA! that's genius Jerry  :grin:
Didn't even think of that.

I was only considering it when someone mentioned (maybe you) pulling in a full volume of air at night was likely adding unnecessary moisture to the interior of the FARS causing higher than usual RH readings during the day.  Of course, If this is not the case, than I will forego that experiment and leave it as is. Very Humid and Very little air here.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: Bobvelle on August 16, 2018, 09:06:55 PM



 
Broke down FARS against each shield for cleaner comparision


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Great Info!
Are the temps at the top the Average or standard deviation or...?
It Looks like my standard Meteo is doing about as good as your Pro...I'm only getting 1.5 -2 deg difference in the sun too Hmm
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 16, 2018, 10:05:15 PM



 
Broke down FARS against each shield for cleaner comparision


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Great Info!
Are the temps at the top the Average or standard deviation or...?
It Looks like my standard Meteo is doing about as good as your Pro...I'm only getting 1.5 -2 deg difference in the sun too Hmm

No should have been clear those are peak max differentials, may only happened once but when you report highs and lows thats all they look at.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: dendrite on August 16, 2018, 10:17:46 PM
i don't have extreme heat
heh. I think 99% of the forum had to laugh at that one. ;)
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: openvista on August 16, 2018, 10:44:27 PM



 
Broke down FARS against each shield for cleaner comparision


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Great Info!
Are the temps at the top the Average or standard deviation or...?
It Looks like my standard Meteo is doing about as good as your Pro...I'm only getting 1.5 -2 deg difference in the sun too Hmm

Well, what's your wind like? Looks like Randy hit a max of 2mph the entire test period today! That's about as good as it gets for testing shields. If there were any errors to be found, they'd be sure to show up.

EDIT: missed that you posted 1.5mph avg wind. Randy didnt give an average but his appears to be lower just looking at his graph. That might explain the discrepancy.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: Old Tele man on August 16, 2018, 11:26:09 PM
In WEATHER as in REAL ESTATE, it's all about LOCATION, LOCATION, LOCATION ( :roll: )!
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 16, 2018, 11:52:46 PM
Here is one to ponder everyone. The KVTN ASOS 1.3 mi distance, High was 87.1 today. That's still 2 warmer than the warmest shield (Standard).
So any of these shields looked stellar when comparing with the ASOS FARS  #-o
So the hard sucking FARS doesnt matter, geography really makes the big difference. I'm sure I have my own summer micro climate with all the vegetation.
 
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: openvista on August 17, 2018, 12:16:10 AM
Here is one to ponder everyone. The KVTN ASOS 1.3 mi distance, High was 87.1 today. That's still 2 warmer than the warmest shield (Standard).
So any of these shields looked stellar when comparing with the ASOS FARS  #-o
So the hard sucking FARS doesnt matter, geography really makes the big difference. I'm sure I have my own summer micro climate with all the vegetation.
 

Looks like your other station (E7498), outside of town, hit 84 (still with the 7714?). So with more trees/turf around in town, 83 (FARS high) could be accurate. Either way, 83/84 seems entirely plausible to me. 

As for the airport, that's a head scratcher. Didn't you say that the local COOP observer has also been showing lower temps than the airport since the jump last year?
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: CW2274 on August 17, 2018, 12:36:22 AM
That's still 2 warmer than the warmest shield (Standard).
So any of these shields looked stellar when comparing with the ASOS FARS  #-o
Well, not if they were side by side. I mean, you yourself verified the ASOS temp was spot on accurate only 2 or 3 weeks ago, right?
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: openvista on August 17, 2018, 12:47:18 AM
Thinking further about it... on a day with almost no wind heat can easily stagnate in one area. Tons of microclimates develop. The additional plant life in town could moderate and absorb some of the heat in places. Not sure you can read too much into the airport temp on such a day.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 17, 2018, 08:07:55 AM
It is a head scratcher and yes the other station similar to AP was also 84 with the 7714. Yes I did the airport test a week ago, high temp was right but low was +1.4 high,  so something still amiss I think . The Coop is in town so would have similar readings to what I have.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 17, 2018, 09:11:44 AM
Update I was asked if I would continue testing all shields for long term study.
So guess Ill set up the shields a little different instead of using tripod I need a permanent setup.
Another project and yes I enjoy stuff like this as you can imagine.


Heard back from Allmeteo and got refunded for standard. Sent them all my data in CVS form from test.
Also ordered a second Pro unit for remote site.

I do think the Pro is as good as any passive shield can get even surpassing the highly regarded 7714. 

Those that have a breeze like Jerry living on the Gulf will never miss the FARS. If you are in the desert I wouldn't change over however.

Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: dendrite on August 17, 2018, 09:26:58 AM
Update I was asked if I would continue testing all shields for long term study.
So guess Ill set up the shields a little different instead of using tripod I need a permanent setup.
Another project and yes I enjoy stuff like this as you can imagine.


Heard back from Allmeteo and got refunded for standard. Sent them all my data in CVS form from test.
Also ordered a second Pro unit for remote site.

I do think the Pro is as good as any passive shield can get even surpassing the highly regarded 7714. 

Those that have a breeze like Jerry living on the Gulf will never miss the FARS. If you are in the desert I wouldn't change over however.
Tell them you'd be glad to, but you need one of their temp/hum probes free of charge too. ;)

It actually looks like they use the SHT75 based on the specs. +/- 1.8% RH is usually a dead giveaway.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 17, 2018, 10:45:17 AM
Update I was asked if I would continue testing all shields for long term study.
So guess Ill set up the shields a little different instead of using tripod I need a permanent setup.
Another project and yes I enjoy stuff like this as you can imagine.


Heard back from Allmeteo and got refunded for standard. Sent them all my data in CVS form from test.
Also ordered a second Pro unit for remote site.

I do think the Pro is as good as any passive shield can get even surpassing the highly regarded 7714. 

Those that have a breeze like Jerry living on the Gulf will never miss the FARS. If you are in the desert I wouldn't change over however.
Tell them you'd be glad to, but you need one of their temp/hum probes free of charge too. ;)

It actually looks like they use the SHT75 based on the specs. +/- 1.8% RH is usually a dead giveaway.

They did say keep the standard and sending out free Pro for my trouble.  (not really trouble if you enjoy it)  Instead of slimming down I just spent $40 concreting 2 more poles in for better separation so committed now and have more stuff to mow around LOL
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: Bobvelle on August 17, 2018, 11:42:39 AM



 
Broke down FARS against each shield for cleaner comparision


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Great Info!
Are the temps at the top the Average or standard deviation or...?
It Looks like my standard Meteo is doing about as good as your Pro...I'm only getting 1.5 -2 deg difference in the sun too Hmm

Well, what's your wind like? Looks like Randy hit a max of 2mph the entire test period today! That's about as good as it gets for testing shields. If there were any errors to be found, they'd be sure to show up.

EDIT: missed that you posted 1.5mph avg wind. Randy didnt give an average but his appears to be lower just looking at his graph. That might explain the discrepancy.

His does "look" closer, but then again, his index lines are 5 deg apart.  :-)

I'm not making the claim that the standard is just as good as the Pro... I was just surprised that the standard did that well in my comparative test. After making things more equal between the FARS and the standard Meteo shield, I went back and compared the 14th graph (FARS mostly shaded) and the 16th graph (both getting equal exposure) and the difference narrowed by .5 deg. So there was some improvement.
Moreover, I'm pretty sure that if i shaded the Meteo Standard and the FARS during peak sun hours the numbers would be even closer given the same wind, or lack there of.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: openvista on August 17, 2018, 12:51:24 PM
His does "look" closer, but then again, his index lines are 5 deg apart.  :-)

I'm not making the claim that the standard is just as good as the Pro... I was just surprised that the standard did that well in my comparative test.

I meant that his wind graph seems to indicate his average wind was lower than 1.5mph. If, indeed, your winds were higher that would explain why the standard shield did better in your tests.

Of course, you could argue you had higher solar insolation than him because of your more southerly latitude so that should cancel any slight wind advantage he had.

Scientific studies of any kind, even the informal ones being conducted in this thread, live and die on small details that may be imperceptible or difficult to quantify.

Sure, moving the shield to shade may help, but you'd also be measuring air less directly heated by the sun. On a calm day there could be a noticeable difference. IMO, a solar radiation shield that doesn't perform well in the sun is a bad solar radiation shield.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: Bobvelle on August 17, 2018, 01:25:08 PM
His does "look" closer, but then again, his index lines are 5 deg apart.  :-)

I'm not making the claim that the standard is just as good as the Pro... I was just surprised that the standard did that well in my comparative test.

 IMO, a solar radiation shield that doesn't perform well in the sun is a bad solar radiation shield.
Agreed. But the only thing I know of that would not allow ANY heat (radiation) from affecting the enclosed sensor in stagnate air environment would be a lead lined vacuum chamber. Heat is going to find its way in to affect the reading no matter how well it's made, if there is little to no wind. So does a "good" radiation shield even exist?
I honestly don't know..just asking the question.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 17, 2018, 01:36:07 PM
Average wind speed was really low yesterday, highest I saw was .2 MPH and not much better today.
New setup image. Concrete is still drying, the standard shield needs straightened after it dries little more.

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Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: openvista on August 17, 2018, 01:39:01 PM
I'm going to report a bit early today because we have some smoke moving in from Canadian wildfires soon. It's been clear all morning so far.

Just looking at the past 2 hours of data (11AM - 1PM EDT) the 7714 is dead even with the FARS in avg temp (0.08F diff). However, the FARS max temp in those 2 hours was 0.5F warmer than the 7714. Avg wind speed at 28ft was 3.33mph. I'd guess 3mph or less at 20ft (7714) and under 2mph at 5ft (FARS).

So.... my guess is the height differential plays in significantly here. The FARS is about 20 ft from a two lane residential paved road. It's about 30 ft from a 3 car width driveway (that's about 25 feet long). Perhaps being up and away from that radiation in a more mixed environment gives a truer picture of mesoscale conditions? Could also just be the old rule of higher is cooler (standard lapse rate under high pressure). Hard to say what is the ideal siting here. Although the agreement overall, especially at night, between the two shields is remarkable.

I can't easily move my FARS up to 20', but I suspect that if I did, though, the FARS would run even cooler than the 7714. Although the point for me isn't to find the coolest spot on the property. It's to find where a passive, backup shield best matches my active shield. I think I may have found the spot, but it's still early going. Need to see some clear nights and, ideally, some clear days with a blanket of fresh snow. That'll be awhile assuming the snow gods aren't in a perverse mood  ;).
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: dendrite on August 17, 2018, 01:51:21 PM
Average wind speed was really low yesterday, highest I saw was .2 MPH and not much better today.
New setup image. Concrete is still drying, the standard shield needs straightened after it dries little more.

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Looks like Davis HQ. lol

In the pics of the shields I see on their site, it looks like the "gills" slope downward from the mounting bracket outward. Yours seem to be in the opposite direction, sloping upward. Is it possible to switch them around 180 degrees so that they're sloping downward toward the south side? Maybe it wouldn't make a difference...just an idea. I'm assuming your mounting arms are already aiming S based on the shadows in your pic.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 17, 2018, 02:07:40 PM
Average wind speed was really low yesterday, highest I saw was .2 MPH and not much better today.
New setup image. Concrete is still drying, the standard shield needs straightened after it dries little more.

 [ You are not allowed to view attachments ]
Looks like Davis HQ. lol

In the pics of the shields I see on their site, it looks like the "gills" slope downward from the mounting bracket outward. Yours seem to be in the opposite direction, sloping upward. Is it possible to switch them around 180 degrees so that they're sloping downward toward the south side? Maybe it wouldn't make a difference...just an idea. I'm assuming your mounting arms are already aiming S based on the shadows in your pic.
I'll take a look see if I figure out what you see.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: dendrite on August 17, 2018, 02:15:01 PM
Average wind speed was really low yesterday, highest I saw was .2 MPH and not much better today.
New setup image. Concrete is still drying, the standard shield needs straightened after it dries little more.

 [ You are not allowed to view attachments ]
Looks like Davis HQ. lol

In the pics of the shields I see on their site, it looks like the "gills" slope downward from the mounting bracket outward. Yours seem to be in the opposite direction, sloping upward. Is it possible to switch them around 180 degrees so that they're sloping downward toward the south side? Maybe it wouldn't make a difference...just an idea. I'm assuming your mounting arms are already aiming S based on the shadows in your pic.
I'll take a look see if I figure out what you see.
The gills slope downward from the mounting bracket side in these images.

https://www.allmeteo.com/meteo-shop/?category=Temperature
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: openvista on August 17, 2018, 02:36:24 PM
His does "look" closer, but then again, his index lines are 5 deg apart.  :-)

I'm not making the claim that the standard is just as good as the Pro... I was just surprised that the standard did that well in my comparative test.

 IMO, a solar radiation shield that doesn't perform well in the sun is a bad solar radiation shield.
Agreed. But the only thing I know of that would not allow ANY heat (radiation) from affecting the enclosed sensor in stagnate air environment would be a lead lined vacuum chamber. Heat is going to find its way in to affect the reading no matter how well it's made, if there is little to no wind. So does a "good" radiation shield even exist?
I honestly don't know..just asking the question.

Very good question. The WMO study actually found that all selected shields measured warmer than a sonic anemometer they were using as a control (because they are immune to solar radiation). Unfortunately, they had to dump the anny data due to a technicality. That's why I found it curious that they said the FARS ran colder than the reference shield at times but then admitted that reality itself was significantly colder at all times!

Regardless, I think it all goes back to what can you live with. For each of us that's going to be different. For me, I just want a station that conforms to modern, accepted measurement standards and best practice to the extent that's possible in an urban neighborhood. Since almost no one uses sonic anemometers to measure temperature (because they are a bear to set up properly and keep calibrated for temperature measurement), the modern gold standard is an aspirated shield. Forecasts are based on such data.

I track forecast accuracy (https://marquetteweather.com/fx_accuracy.php (https://marquetteweather.com/fx_accuracy.php)) and over the past year, my temps average (net) about 1F warm for highs and lows up to 3 days out compared to the NWS point forecast. I'm within 3F about 70% of the time (same day forecasts). I'd say that's excellent given my location in a city lacking accurate model output statistics (the basis for climatology in weather models) and being mere blocks from poorly-modeled Lake Superior that LOVES to throw curve balls.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 17, 2018, 02:50:19 PM
Average wind speed was really low yesterday, highest I saw was .2 MPH and not much better today.
New setup image. Concrete is still drying, the standard shield needs straightened after it dries little more.

 [ You are not allowed to view attachments ]
Looks like Davis HQ. lol

In the pics of the shields I see on their site, it looks like the "gills" slope downward from the mounting bracket outward. Yours seem to be in the opposite direction, sloping upward. Is it possible to switch them around 180 degrees so that they're sloping downward toward the south side? Maybe it wouldn't make a difference...just an idea. I'm assuming your mounting arms are already aiming S based on the shadows in your pic.
I'll take a look see if I figure out what you see.
The gills slope downward from the mounting bracket side in these images.

https://www.allmeteo.com/meteo-shop/?category=Temperature

Here is close-up. Does this still look different?
Shield came together all I did is mount sensor and bottom bracket.

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Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: havtrail on August 17, 2018, 03:00:29 PM
Average wind speed was really low yesterday, highest I saw was .2 MPH and not much better today.
New setup image. Concrete is still drying, the standard shield needs straightened after it dries little more.

 [ You are not allowed to view attachments ]
Looks like Davis HQ. lol

In the pics of the shields I see on their site, it looks like the "gills" slope downward from the mounting bracket outward. Yours seem to be in the opposite direction, sloping upward. Is it possible to switch them around 180 degrees so that they're sloping downward toward the south side? Maybe it wouldn't make a difference...just an idea. I'm assuming your mounting arms are already aiming S based on the shadows in your pic.
I'll take a look see if I figure out what you see.
The gills slope downward from the mounting bracket side in these images.

https://www.allmeteo.com/meteo-shop/?category=Temperature

I think it's simply that one view is from the right side of the bracket and the other view is from the left side of the bracket.
Helixes will do that...

Rich K.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: Bobvelle on August 17, 2018, 03:03:07 PM
If you dismount the bracket, spin 180 and reattach, it will look identical to Allmeteo's photos.

Wish I had one  :sad:

Edit: Or maybe just spin it around like Rich K. says.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 17, 2018, 09:18:35 PM
This is how most would mount for sensor cable to reach, so gave it a try. The 16" pizza pan is optional.  :-)

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Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: Bobvelle on August 17, 2018, 09:31:44 PM
I like it!

Your neighbors must think your a nut though  :lol:
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 17, 2018, 09:40:43 PM
Probably!
I picked the 16" pizza pan up at dollar general cheap. Its bolted on to the base of Davis mount so I drilled a hole in shield directly under the ISS for cable to reach.
I got almost done and realized the solar mount needed to go on first before the shield.  ](*,)  Anyway 2 more to go should go faster I have all the hardware now.  Im going to mount the standard same way so all are equal.
It actually cleaned the area up getting the solar cells above the shield and looks pretty good.

Oh! Almost forgot I used a rubber insulation on shield side of pizza pan. This is same stuff you line floor boards with & maybe hard to find. I already had a big roll and its super sticky once on it doesn't come off.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: Bobvelle on August 17, 2018, 09:49:00 PM
I had trouble keeping my meteo bracket stable with just one U-bolt. Had to use 2, I guess your not having an issue with it?

So your still going to be testing the standard? Thought you were going to give up on it.
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: CW2274 on August 17, 2018, 10:07:57 PM
I picked the 16" pizza pan up at dollar general cheap.
Pizza pan... :???:
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 17, 2018, 10:38:01 PM
I had trouble keeping my meteo bracket stable with just one U-bolt. Had to use 2, I guess your not having an issue with it?

So your still going to be testing the standard? Thought you were going to give up on it.

Long term testing.

This is some of the things they are looking at:

Recovery of air temperature & humidity after rain as compared to the FARS & 7714 & Professional

How it compares to the 7714 in non-ideal installations near sources of infrared radiation like over grassless terrain, farmland, near pavement or sun-exposed walls.
 
Long-term sensor protection from dirt buildup.


I'm giving them non-typical installations like using a Davis sensor vs probe type,  16 diameter shield, Davis rain bucket, exposure to ISS solar cells and whatever else I can through at them.

They have all the typical data so Im giving data thats unusual. 



Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 17, 2018, 10:45:20 PM
Here is bottom view.
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Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: CW2274 on August 17, 2018, 11:12:40 PM
I had trouble keeping my meteo bracket stable with just one U-bolt. Had to use 2, I guess your not having an issue with it?

So your still going to be testing the standard? Thought you were going to give up on it.
16 diameter shield
They have all the typical data so Im giving data thats unusual.
So you're shielding their shield....
Kinda defeats the purpose of what it's suppose to be in the first place isn't it, a competent shield?
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: ValentineWeather on August 18, 2018, 12:04:29 AM
I had trouble keeping my meteo bracket stable with just one U-bolt. Had to use 2, I guess your not having an issue with it?

So your still going to be testing the standard? Thought you were going to give up on it.
16 diameter shield
They have all the typical data so Im giving data thats unusual.
So you're shielding their shield....
Kinda defeats the purpose of what it's suppose to be in the first place isn't it, a competent shield?

What did I just say? I'm doing what I want,  if I can make it better, I will. I don't care about their stock shield. Everything can be improved. 
The 7714 is no longer stock. It performs better with black inside.
The FARS is no longer stock with the AC fan. Even my Cocorahs gauge is better than the original design with the deeper funnel. I dont like anything stock. Cars, trucks, ATVs first thing I do is start making it better.
I tried that on my wife too, but didnt go over well  ;)
 
Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: SnowHiker on August 18, 2018, 04:11:47 AM
This 454 Chevy engine could aspirate all your shields at once:

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Title: Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
Post by: Bashy on August 18, 2018, 06:40:58 AM
I had trouble keeping my meteo bracket stable with just one U-bolt. Had to use 2, I guess your not having an issue with it?

So your still going to be testing the standard? Thought you were going to give up on it.
16 diameter shield
They have all the typical data so Im giving data thats unusual.
So you're shielding their shield....
Kinda defeats the purpose of what it's suppose to be in the first place isn't it, a competent shield?

What did I just say? I'm doing what I want,  if I can make it better, I will. I don't care about their stock shield. Everything can be improved. 
The 7714 is no longer stock. It performs better with black inside.
The FARS is no longer stock with the AC fan. Even my Cocorahs gauge is better than the original design with the deeper funnel. I dont like anything stock. Cars, trucks, ATVs first thing I do is start making it better.
I tried that on my wife too, but didnt go over well  ;)
 

I take it the test is now void seen as you are modifying the shields? i was following this with great interest