Author Topic: (Sensiron SHT31) with 25 foot Cable (7.6m)  (Read 3315 times)

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Offline ValentineWeather

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(Sensiron SHT31) with 25 foot Cable (7.6m)
« on: July 18, 2017, 05:33:13 PM »
Noticed Scaled has this in stock with 25' cable.
Plans to mount one of my 24 hr fars shields toward top of 33' anemometer mass. Why?  I want to see if temperatures at that level are similar to away from humid in town conditions lawns, trees , grass etc. It's another experiment.
Curious what the overnight lows do at that height also.
 
Davis 7346.221 - Digital Temperature Humidity Sensor (Sensiron SHT31) with 25 foot Cable (7.6m)
Randy

Offline CW2274

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Re: (Sensiron SHT31) with 25 foot Cable (7.6m)
« Reply #1 on: July 18, 2017, 06:36:03 PM »
 8-)

Offline WxLover16

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Re: (Sensiron SHT31) with 25 foot Cable (7.6m)
« Reply #2 on: July 18, 2017, 07:29:31 PM »
Testing aspirated 31's at different heights sounds like fun to me. Let us know.  :grin:

Off-topic, but it's interesting to unplug (for about 5 minutes or so) and plug my fan back in and see how much difference it makes. Not very scientific but it always seems to go down about 2 degrees rather fast. Love me some ACF aspiration!  :grin: \:D/
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Offline WxLover16

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Re: (Sensiron SHT31) with 25 foot Cable (7.6m)
« Reply #3 on: July 18, 2017, 08:54:14 PM »
Far Aspiration analogy:

Stand in the Sun...get hot = no FARS

Stand in the Shade...not as hot = FARS

This. Nice Summary  ;)
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Offline Bashy

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Re: (Sensiron SHT31) with 25 foot Cable (7.6m)
« Reply #4 on: July 19, 2017, 02:07:00 AM »
I read that there is not a lot of difference from the standard height to the 10m (33ft) height and generally better for the backyard
weather enthusiast, the most beneficial aspect is the fact that there is more of a breeze due to not being susceptible to dead spots
caused by buildings and structures.

"Not a lot of difference" compared to a properly sited temp/hum, i.e, standard height in an open grassy field.
Kind regards
Bashy

Offline ValentineWeather

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Re: (Sensiron SHT31) with 25 foot Cable (7.6m)
« Reply #5 on: July 19, 2017, 06:17:06 AM »
I read that there is not a lot of difference from the standard height to the 10m (33ft) height and generally better for the backyard
weather enthusiast, the most beneficial aspect is the fact that there is more of a breeze due to not being susceptible to dead spots
caused by buildings and structures.

"Not a lot of difference" compared to a properly sited temp/hum, i.e, standard height in an open grassy field.

Yes, not much difference normally with exception off night time lows may run higher with air staying mixed and not decouple at night but each area can differ somewhat. I've done 10-11' before but wanted to try 20+ to see if I can get high enough above the ground vegetation to simulate areas out of town during summer months. I really doubt it but not 100% sure so I'm experimenting.
 
Randy

Offline Bashy

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Re: (Sensiron SHT31) with 25 foot Cable (7.6m)
« Reply #6 on: July 19, 2017, 06:39:10 AM »
I am up 13 foot, and early morning the Davis is about 0.5C Colder, that I can live with cause in direct sun the OS is 1C+ on the Davis
Kind regards
Bashy

Offline alexstaar

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Re: (Sensiron SHT31) with 25 foot Cable (7.6m)
« Reply #7 on: July 20, 2017, 10:49:12 PM »
I have the SHT31 mounted in a non-aspirated shield at 0.5 meter (1.5 feet) above the ground directly underneath my ISS (24 hour FARS) also with the SHT31 mounted at 2 meters (~6 feet). Today the 0.5m temp rose to 97ºF while the 2m temp rose to only 93.3ºF. You will also see substantial differences at 10m (33 feet). We have a setup of 4 Vaisala sensors on campus at UAH. See the 0.5m, 1m, 2m, and 10m temp sensors and data here: http://www.nsstc.uah.edu/mips/data/current/surface/

*Note: the RH sensor (and calculated dewpoint) currently has a low bias.

**Note 2: all radiation shields at the site on campus are identical and non-aspirated.
« Last Edit: July 20, 2017, 11:00:33 PM by alexstaar »
-Alex

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Offline ValentineWeather

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Re: (Sensiron SHT31) with 25 foot Cable (7.6m)
« Reply #8 on: July 23, 2017, 01:34:18 PM »
Mounted solar 24 hr. fars shield on anemometer mask and seeing about what was experienced once before in Arizona cooler daytime temps. At this elevation around 22' I'm seeing  1.5-2.2° F thus far. Humidity about the same but variable with temperature. 

Here is snapshot currently it's been like this for almost an hour now running couple degrees cooler.

I have these 3 shields all recording so will watch data for next few days and post results if interesting. 
My immediate thought those without ideal location for shield. IE small backyard this may work better than reporting overly warm temperatures low airflow backyard.
Randy

Offline Bashy

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Re: (Sensiron SHT31) with 25 foot Cable (7.6m)
« Reply #9 on: July 23, 2017, 02:47:17 PM »

My immediate thought those without ideal location for shield. IE small backyard this may work better than reporting overly warm temperatures low airflow backyard.

basically what i said....
Kind regards
Bashy

Offline ValentineWeather

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Re: (Sensiron SHT31) with 25 foot Cable (7.6m)
« Reply #10 on: July 23, 2017, 07:24:23 PM »
First look daytime. TX1 6' AC powered fan , TX2 is 20' Davis solar fan , TX4 6' Davis solar fan.
Today light winds 5-8 mph and sunny.

20' is averaging around 2°F cooler over both ground level shields and 3° cooler on occasion. 
« Last Edit: July 23, 2017, 07:26:19 PM by ValentineWeather »
Randy

Offline CW2274

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Re: (Sensiron SHT31) with 25 foot Cable (7.6m)
« Reply #11 on: July 23, 2017, 08:21:09 PM »
First look daytime. TX1 6' AC powered fan , TX2 is 20' Davis solar fan , TX4 6' Davis solar fan.
Today light winds 5-8 mph and sunny.

20' is averaging around 2°F cooler over both ground level shields and 3° cooler on occasion.
What frankly surprises me more is not the 20' reading, but how much cooler the a/c is over the stock fan. Not only that, the a/c seems to be slightly more linear. Didn't see that coming.
BTW, I know you enjoy this, but thanks for your work.

Offline WxLover16

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Re: (Sensiron SHT31) with 25 foot Cable (7.6m)
« Reply #12 on: July 23, 2017, 09:49:27 PM »
First look daytime. TX1 6' AC powered fan , TX2 is 20' Davis solar fan , TX4 6' Davis solar fan.
Today light winds 5-8 mph and sunny.

20' is averaging around 2°F cooler over both ground level shields and 3° cooler on occasion.
What frankly surprises me more is not the 20' reading, but how much cooler the a/c is over the stock fan. Not only that, the a/c seems to be slightly more linear. Didn't see that coming.
BTW, I know you enjoy this, but thanks for your work.

Yeah, this is to us like a kid finding candy in a candy store. We'd all love to be able to do these tests. I can only imagine how cool it is for Randy to be experiencing/doing this first hand.
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Offline WxLover16

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Re: (Sensiron SHT31) with 25 foot Cable (7.6m)
« Reply #13 on: July 23, 2017, 09:55:17 PM »
Yes generally today the AC was cooler except final HIGH. It was .4 more.  :-P

Are you running any batteries in the 24 hr solar fan?
Davis Wireless VP2 SHT31 24hr 24CFM FARS

Offline ValentineWeather

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Re: (Sensiron SHT31) with 25 foot Cable (7.6m)
« Reply #14 on: July 23, 2017, 10:06:58 PM »
Yes generally today the AC was cooler except final HIGH. It was .4 more.  :-P

Are you running any batteries in the 24 hr solar fan?

Yes both solar Fars are the 24 hour version.
Randy

Offline WxLover16

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Re: (Sensiron SHT31) with 25 foot Cable (7.6m)
« Reply #15 on: July 23, 2017, 10:23:20 PM »
Yes generally today the AC was cooler except final HIGH. It was .4 more.  :-P

Are you running any batteries in the 24 hr solar fan?

Yes both solar Fars are the 24 hour version.

I know, just was wondering if you were using batteries, 1 or both. IMO, it would be cool to remove the batteries to see how much closer the stock is at full power at peak heating compared to the AC but that's just me.
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Offline ValentineWeather

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Re: (Sensiron SHT31) with 25 foot Cable (7.6m)
« Reply #16 on: July 24, 2017, 07:55:51 AM »
I have a confession the solar fars is over an area of yard with dead grass and more bare ground. I did this by design thanks to drought decided to not water upper portion of yard and move sensor shield over area to simulate more natural conditions.

When it was closer to AC powered over grass the daytime readings were much closer. (Couple tenths) The ground is a major player in what temperatures are being recorded.

At one time grass was planted under most all the Stevenson screens and now many shelters are over gravel, bare ground and even located close to asphalt so I feel this also is why we are seeing an increase around the country
Randy

Offline ValentineWeather

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Re: (Sensiron SHT31) with 25 foot Cable (7.6m)
« Reply #17 on: July 24, 2017, 08:28:36 AM »
Here are lows 24 hr fars with #1-AC powered over grass, #2-20' DC solar on battery anemometer mask, #4-DC powered on battery over bare/dead grass.  Both 1&4 6' mounted shields lows 64.7. #2 at 20' 65.0.

The 20' shield was only .3 warmer. Light winds overnight played a roll I'm sure.

So there you have it after first full day of testing, daytime highs significantly cooler at 20' around 2° on average, nighttime lows hung about a degree warmer during most of night but toward daybreak came within .3F.
Randy

Offline alexstaar

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Re: (Sensiron SHT31) with 25 foot Cable (7.6m)
« Reply #18 on: July 26, 2017, 12:01:33 AM »
Very nice results. Keep them coming!
-Alex

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Offline ValentineWeather

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Re: (Sensiron SHT31) with 25 foot Cable (7.6m)
« Reply #19 on: July 26, 2017, 06:28:37 AM »
Very nice results. Keep them coming!

Sorry I got the information needed when I realized daytime temps were that much cooler at 20' so took down yesterday morning. i had retracted the 30' telepole one full section for the experiment so not to have that much weight so far up. Shield needed to be on that section for mounting clamp purpose and was concerned about the extra weight swaying so didn't extend pole fully.
Randy