Author Topic: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD  (Read 17080 times)

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Offline openvista

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Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
« Reply #325 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.
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Offline ValentineWeather

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Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
« Reply #326 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 ]
Randy

Offline ValentineWeather

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Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
« Reply #327 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
« Last Edit: August 15, 2018, 08:39:58 AM by ValentineWeather »
Randy

Offline Bobvelle

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Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
« Reply #328 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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« Last Edit: August 15, 2018, 08:24:53 AM by Bobvelle »

Offline ValentineWeather

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Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
« Reply #329 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:
Randy

Offline ValentineWeather

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Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
« Reply #330 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.
Randy

Offline Bobvelle

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Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
« Reply #331 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.
« Last Edit: August 15, 2018, 10:43:52 AM by Bobvelle »

Offline Bobvelle

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Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
« Reply #332 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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« Last Edit: August 15, 2018, 11:59:04 AM by Bobvelle »

Offline dendrite

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Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
« Reply #333 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.

Offline Bobvelle

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Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
« Reply #334 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.

Offline Bobvelle

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Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
« Reply #335 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:
« Last Edit: August 15, 2018, 12:12:21 PM by Bobvelle »

Offline Bobvelle

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Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
« Reply #336 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?
« Last Edit: August 15, 2018, 12:36:27 PM by Bobvelle »

Offline dendrite

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Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
« Reply #337 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.

Offline Bobvelle

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Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
« Reply #338 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.

Offline ValentineWeather

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Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
« Reply #339 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.
« Last Edit: August 15, 2018, 02:27:40 PM by ValentineWeather »
Randy

Offline ValentineWeather

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Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
« Reply #340 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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« Last Edit: August 15, 2018, 02:08:48 PM by ValentineWeather »
Randy

Offline ValentineWeather

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Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
« Reply #341 on: August 15, 2018, 05:25:47 PM »
One guess.
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Randy

Offline Bobvelle

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Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
« Reply #342 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.

Offline openvista

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Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
« Reply #343 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.
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Offline dendrite

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Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
« Reply #344 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?

Offline ValentineWeather

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Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
« Reply #345 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
Randy

Offline ValentineWeather

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Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
« Reply #346 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.
Randy

Offline ValentineWeather

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Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
« Reply #347 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.
Randy

Offline dendrite

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Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
« Reply #348 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?

Offline ValentineWeather

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Re: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD
« Reply #349 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.
Randy