Author Topic: Temperature Shield Question (Read 6450 times)

LTCSZ · « **on:** May 06, 2011, 09:11:21 PM »

Hi: I'm using an AW 1090 Fine Offset station...I have it in the optional shield (the big one) mounted on a fence about 5 feet off of the ground...It is in direct sunlight about half of the day, but I thought the "solar" shield was supposed to compensate for that...My temperature readings are still consistantly higher than the surrounding neighborhood stations, the NWS, and another wireless temp only station I have on my deck..I know there are always slight variations from spot to spot, but not 15-20 degrees...Would it be a good idea to build a simple "roof" over the shield, or go back to the original smaller shield under a cover?...The temp values are seriously affecting other things like my dewpoint calculations, etc...Plus, it's frustrating! Any advice will be appreciated!

Steve in Kansas

utahweatherbear · « **Reply #1 on:** May 06, 2011, 09:25:20 PM »

what type of fence? is it a dark color? what is your proximity to south facing walls? what is the ground type along the fence? a picture would help.

DanS · « **Reply #2 on:** May 06, 2011, 09:26:55 PM »

A possibility the fence is radiating the additional heat? Could try a post out in the yard and 5 feet up. I see utahweatherbear is having the same thoughts.

LTCSZ · « **Reply #3 on:** May 06, 2011, 09:44:41 PM »

Thanks for getting back to me...Here are two pictures of the station...Again, thanks for your help and patience...

Steve

utahweatherbear · « **Reply #4 on:** May 06, 2011, 09:50:43 PM »

Hmmm...my best guess would be heat is radiating off the fence, especially if the sun is hitting that side. Even if the sun is hitting the other side, those boards will be getting pretty warm and your shield is just to close. You also will see restricted airflow there. I would either try to raise it couple feet above the fence, or get it away from the fence all together if possible.

DanS · « **Reply #5 on:** May 06, 2011, 10:02:06 PM »

If you have space, may be you could install another 4x4 post out in your yard and move the equipment there, away from the fence.

LTCSZ · « **Reply #6 on:** May 06, 2011, 10:04:14 PM »

I think you might be correct...When the sun goes down, my readings are right in line with others in the area...I will do some playing around with the location tomorrow and see what hapens...More to come! Thanks again,

Steve

LTCSZ · « **Reply #7 on:** May 06, 2011, 10:12:42 PM »

Another quick one...Would I be better off going with the smaller shield that came with the station? I could place it back on the pole with the other instruments...Thanks again...

utahweatherbear · « **Reply #8 on:** May 06, 2011, 10:17:54 PM »

If you could somehow get it on that pole with the big shield that would be best. The bigger the sheild, the better job it does. Not a big fan of the smaller sheilds with some of these stations.

DanS · « **Reply #9 on:** May 06, 2011, 10:19:52 PM »

Quote from: LTCSZ on May 06, 2011, 10:12:42 PM

Another quick one...Would I be better off going with the smaller shield that came with the station? I could place it back on the pole with the other instruments...Thanks again...

No, the radiation shield you're using now is far better than the stock/supplied "weather shield". Also, mounting the sensors on the pole where it is now puts your temp sensor in the rising heat off the fence.

Your radiation shield is far better and keeping it away from heat radiators like the fence and any surfaces such as concrete, asphalt, gravel. etc. is the key.

LTCSZ · « **Reply #10 on:** May 06, 2011, 10:27:51 PM »

I'm rapidly running out of locations, given the length of the cord for the connection...Maybe I will try the separate pole idea a few feet out from the fence...Lots to learn...Thanks again...

utahweatherbear · « **Reply #11 on:** May 06, 2011, 10:28:48 PM »

DanS is correct that the pole is still not ideal...but as high up you could get it would be far better than what you have now. I feel 2 or 3 feet above the fence, the heat impact would be minimal...and would be virtually zero with a breeze blowing.

LTCSZ · « **Reply #12 on:** May 06, 2011, 10:32:56 PM »

Think I'll try mounting the large shield to the existing pole up a couple of feet...Don't know how well my 32 year old fence will support the additional weight, but it will at least give me an idea of some options...didn't think it would be this difficult! Thanks for the help and I'll keep you posted...

Steve

DanS · « **Reply #13 on:** May 06, 2011, 10:34:45 PM »

Quote from: LTCSZ on May 06, 2011, 10:27:51 PM

I'm rapidly running out of locations, given the length of the cord for the connection...Maybe I will try the separate pole idea a few feet out from the fence...Lots to learn...Thanks again...

If you decide to use an extension RJ-11 cord watch for (avoid) wiring reversal. That is, make sure that the color order yellow, red, green, black stays the same and the coupler or new cable doesn't flip them around as some do.

utahweatherbear · « **Reply #14 on:** May 06, 2011, 10:36:44 PM »

Yeah, give that a try and see how it works out for a little while. You could always move it again!

DanS · « **Reply #15 on:** May 06, 2011, 10:50:46 PM »

Try this in your sig. May not be the one you want but gives you an idea and you can change it.

Code: [Select]

[url=http://www.wunderground.com/weatherstation/WXDailyHistory.asp?ID=KKSGARDE8][img]http://banners.wunderground.com/cgi-bin/banner/ban/wxBanner?bannertype=wxstnsticker_both&weatherstationcount=KKSGARDE8[/img][/url]

gives you

LTCSZ · « **Reply #16 on:** May 06, 2011, 10:58:01 PM »

Very, very cool...Thanks for the help...I was wondering how to do that!

Steve

LTCSZ · « **Reply #17 on:** May 07, 2011, 11:13:34 AM »

Day two of the temperature challenge: Moved the shield about half way up the mounting pole...Now it
is completely clear of the fence...
Had to do some fancy leveling since the added weight tilted the pole a bit...Now all I have to worry about is the
32 year old fence falling down...I'll let you know later this afternoon if the temps are more in line with
the other area stations...Sure do appreciate the advice...

Steve

LTCSZ · « **Reply #18 on:** May 07, 2011, 04:44:14 PM »

OK...Latest update...Moving the shield up the pole was a bad idea...Temps shot up over ten degrees above any local staion...Tried moving the shield lower and away from the fence...This brought things down a bit to about five degrees over the next highest temp...Improvement, I guess...Looks like I will try building a small roof for the shield out of some junk lumber I have and see if that helps...Guess I'm getting closer...I just cannot imagine that the fence has that much effect...A wireless therometer I have on my deck in the shade currently agrees with almost all the local stations to within a degree...To bad there isn't a way to separate the temp/humidity sensors a long way away from the main unit...But, I am narrowing it down...Just out of curiosity...Are there any stations that allow wireless separation of the various sensors? If they are, I assume they would be quite espensive...As you can tell from the condition of my fence, I don't have a lot of spare cash! Thanks for the help and I'll update soon...

Steve

SlowModem · « **Reply #19 on:** May 07, 2011, 06:43:29 PM »

Quote from: LTCSZ on May 07, 2011, 04:44:14 PM

Are there any stations that allow wireless separation of the various sensors? If they are, I assume they would be quite espensive...As you can tell from the condition of my fence, I don't have a lot of spare cash! Thanks for the help and I'll update soon...

Steve

OS WMR968 allows separation of sensors. Each sensor has it's own solar cell/battery/transmitter. However, I didn't have very good luck with the RH sensor. But, others have had good luck with theirs.

Look around. You might find a better price. There's a John Deere model that's green, but that's the only difference, but sometimes they're cheaper.

Good luck!

LTCSZ · « **Reply #20 on:** May 07, 2011, 07:17:02 PM »

Here's the latest comparison with the nearest stations to me (Hedgehog Alley)...Looks like we might have solved the temp placement issue...

N0KQX, Garden City, KS
87.2 °F

48 °F

26%

Hedgehog Alley, Garden City, KS
87.3 °F

46 °F

27%

APRSWXNET Garden City KS, Garden City, KS
87 °F

48 °F

26%

CAS Airport, Garden City, KS

84.9 °F

45 °F

25%

8.33 NNW GCKS Northshore Circle, Garden City, KS
85.3 °F

DanS · « **Reply #21 on:** May 07, 2011, 07:57:46 PM »

Looks like you may have solved the temp reading issue as you say. Have to take into account micro-climates that will vary the comparisons but you're really close with those readings. I was going to suggest a short extension cable to get away from your "heat generator" (fence) and use a post like this

but appears you may have it already.

LTCSZ · « **Reply #22 on:** May 07, 2011, 08:32:01 PM »

I may still go to something like that, as the fence is right on an alley and there is lots of foot traffic through there...A real temptation for kids...I still want to check the readings for a few days to be sure of my placement and then I may get out the old post hole digger and buy me a 4x4...Thanks for your advice...I will continue to post my results here...

Steve

xykotik · « **Reply #23 on:** May 08, 2011, 08:35:45 AM »

I thought I saw a driveway behind your fence. Is that the alley? You posted that the temp increased again after raising the sensor. Gravel can store/radiate a lot of heat just as concrete and asphalt, right up into your screen since you raised it above the fence, if it is indeed directly behind it.

LTCSZ · « **Reply #24 on:** May 08, 2011, 08:55:26 AM »

The sensor is now located lower, separated from the fence as far as I could get it...Today will be the big test...Supposed to be in the 90's...The shield is now just over grass (or as much grass as I have!), so we'll see what happens...Yes, the alley is gravel and sand...Probably was putting out a lot of heat...
I really appreciate all of the advice I hve been given here on the forum...I'll be back later today!

Steve

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Author Topic: Temperature Shield Question (Read 6450 times)