Author Topic: Siting problem  (Read 1961 times)

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Offline azchrisf

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Siting problem
« on: September 20, 2017, 09:25:28 AM »
OK guys,

After getting the Davis and monitoring CWOP quality feedback, I was getting a Dewpoint 4 degree higher at night vs the day.
This morning I noticed the humidity jumped 10-12% (compared to 3 other stations in the imemdiate vicinity which all agree with each other within 2-3%) when my sprinklers went on at 5:30 and it's stays that way for awhile.

http://weather.gladstonefamily.net/site/F1398?days=3#Data

So, I need to site the station better. But, I have a unique situation and I am not sure where to put it, one location is good for some sensors and not others, etc., this being my major issue - so I need some advice on what to do.

Here is my location, as much as I dont want to post it, I need to so you can see what I'm up against:
https://www.google.com/maps/place/6407+W+Yucca+St,+Glendale,+AZ+85304/@33.5868989,-112.1970786,47a,35y,39.42t/data=!3m1!1e3!4m5!3m4!1s0x872b6a2960da6eb5:0xfc32f5f0260e23e9!8m2!3d33.5872966!4d-112.1969952

The sensor is sitting in the backyard right next to the porch there on the right in the gravel walkway to the gravel on the east on a 10 ft pole.
Obviously it needs to be moved since it's picking up the humidity from the grass watering and the pole was meant to be temporary anyways. I was considering the chimney, but that is all the way up on the 2nd story of the house, and may be too high for temperature readings, plus there is a satellite dish on it pointing south. I could locate the sensor to either side but again worried it's too high and the dish (even though it's plastic) could radiate heat. If I do it on the facia board facing south on the 2nd story, it could be too high too, or the pool humidity could interfere. The east side is a total no-no because the UV/Solar sensors will loose track of the sun when it starts to set, and the east side at ground level is always shaded. The 2nd story eve in the center of the house on the east may work, but again, high and near shingles.

So I am at a loss and need some help.

Any suggestions you guys have, please let me know.
« Last Edit: September 20, 2017, 10:14:31 AM by azchrisf »
Davis Vantage Pro 2 Plus 6163 w/ 8 Transmitters!
Also doing Soil and Leaf 4x
WU: KAZGLEND106 CWOP: FW1398 (F1398) Purpleair: 98793/LAZGLEND8
My setup:
https://www.wxforum.net/index.php?topic=41867.0

Offline dalecoy

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Re: Siting problem
« Reply #1 on: September 20, 2017, 10:46:13 AM »
Question 1:  You can't satisfy both the CWOP and yourself.  So, which do you want to satisfy?

Assuming it's yourself - Question 2:  Where on your property do you want to measure the "weather"?

Remember that it's possible to extend (by wiring) the placement of the solar/UV sensors.  And the same is true of the anemometer (or with additional expense, by RF).  But that's perhaps more than you want to do.

Now, if this were my location, I would seriously consider a tripod mount somewhere in the middle of the grass (SE?), and note that when my sprinklers are running, *MY* humidity will be higher.

But it's your compromise to make.


Offline CW2274

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Re: Siting problem
« Reply #2 on: September 20, 2017, 03:47:56 PM »
Obviously it needs to be moved since it's picking up the humidity from the grass watering
I can't believe you and your neighbors have grass.  :shock:
I'd do like Dale says.

Offline azchrisf

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Re: Siting problem
« Reply #3 on: October 11, 2017, 12:11:31 AM »
I did as you suggested Dale and moved it to the middle of the SE grass at 5ft.
MADIS is still flagging me for Dew point off and on.

I give up, it's a perfect 30 on the siting guide, so I don't know if I am doing something wrong or MADIS is biased to something.
« Last Edit: October 11, 2017, 12:14:59 AM by azchrisf »
Davis Vantage Pro 2 Plus 6163 w/ 8 Transmitters!
Also doing Soil and Leaf 4x
WU: KAZGLEND106 CWOP: FW1398 (F1398) Purpleair: 98793/LAZGLEND8
My setup:
https://www.wxforum.net/index.php?topic=41867.0

Offline dalecoy

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Re: Siting problem
« Reply #4 on: October 11, 2017, 10:13:14 AM »
I did as you suggested Dale and moved it to the middle of the SE grass at 5ft.
MADIS is still flagging me for Dew point off and on.

I give up, it's a perfect 30 on the siting guide, so I don't know if I am doing something wrong or MADIS is biased to something.

Are your dew point measurements being called too high or too low?

MADIS is comparing your measurements to those of other Phoenix stations - many of which are probably sited over sand. 
« Last Edit: October 11, 2017, 10:16:01 AM by dalecoy »

Offline SoMDWx

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Re: Siting problem
« Reply #5 on: October 11, 2017, 10:28:27 AM »
I did as you suggested Dale and moved it to the middle of the SE grass at 5ft.
MADIS is still flagging me for Dew point off and on.

I give up, it's a perfect 30 on the siting guide, so I don't know if I am doing something wrong or MADIS is biased to something.

Are there trees around and above your equipment? If so, then it's not a perfect 30 score....

Jim

Offline dalecoy

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Re: Siting problem
« Reply #6 on: October 11, 2017, 10:37:44 AM »

Are there trees around and above your equipment? If so, then it's not a perfect 30 score....

Jim

Look at the information he posted above.  No trees. 

Offline azchrisf

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Re: Siting problem
« Reply #7 on: October 11, 2017, 10:45:43 AM »
Jim,

Too high. In the morning I expect it for about an hour or two because of the sprinklers.

SoMDWx,
No. The sensor is in a clear spot. Google Earth view of house is posted in original post.

On Sunday 10/8 morning I moved the sensor from 15 ft up on a pole on the side of our back porch on the east to the middle of our backyard grass at 5ft to see if it makes any changes. Better but still complains. The station 0.8 miles from me (KC7FQC (AS304)) always has some OK dewpoint readings. However, his station is mounted on the apex of the house slightly above the roofline, over another roof. From what I've read that should radiate a ton of heat off to the sensor considering one of them is a darker colored roof. His unit is also older than mine. Another station 2 blocks from me (also a Davis) is mounted about 7 ft up, and I follow his humidity within 2% and his temperature about 0.5-0.8. This 2nd guy does not report to CWOP though, he did at one time apparently but stopped for some reason. Also an older Davis (mine is brand new).

But I have moved this thing high (15 ft) to low (5ft), dirt to grass and it's always complaining about my dewpoint mean error.
Like I said it scores a perfect 30 in the CWOP guide for siting (as far as I see). I even pulled it off the pole and moved it around all over the backyard, east and west, and saw no significant difference.

What I am starting to wonder is if I am chasing my tail...
Davis Vantage Pro 2 Plus 6163 w/ 8 Transmitters!
Also doing Soil and Leaf 4x
WU: KAZGLEND106 CWOP: FW1398 (F1398) Purpleair: 98793/LAZGLEND8
My setup:
https://www.wxforum.net/index.php?topic=41867.0

Offline SoMDWx

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Re: Siting problem
« Reply #8 on: October 11, 2017, 10:52:30 AM »

Are there trees around and above your equipment? If so, then it's not a perfect 30 score....

Jim

Look at the information he posted above.  No trees.

sorry, don't see this in his original post... :roll:

Offline dalecoy

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Re: Siting problem
« Reply #9 on: October 11, 2017, 11:33:13 AM »

Too high. In the morning I expect it for about an hour or two because of the sprinklers.

..... Another station 2 blocks from me (also a Davis) is mounted about 7 ft up, and I follow his humidity within 2% and his temperature about 0.5-0.8. ....

...What I am starting to wonder is if I am chasing my tail...

No, but you have done the absolute best you can do to report the local conditions at your home.  If any tail-chasing is going on, it's by MADIS, which is looking at a bunch of local averages.

Offline SnowHiker

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Re: Siting problem
« Reply #10 on: October 11, 2017, 02:02:02 PM »

Here is my location, as much as I dont want to post it, I need to so you can see what I'm up against:

You can post just the photo and edit out the link with your address, lat/lon, etc. from your OP.
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