[TowerTalk] WX Sensor Placement

[n4uu73]

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-------- Original message --------From: Patrick Greenlee <patrick_g at windstream.net> Date: 3/3/19  2:18 PM  (GMT-05:00) To: towertalk at contesting.com Subject: Re: [TowerTalk] WX Sensor Placement Our master suite is ICF construction so there are two layers of 2 1/4 inches of Styrofoam separated by 8 inches of steel reinforced concrete in the exterior walls.  This space can be heated with a candle and cooled with an ice cube, really well insulated and virtually no in/exfiltration.  yet an RF linked outdoor thermometer within a foot of the brick veneer reads 5-10 degrees F warmer than when placed 10 ft away on cold winter night temps. I was surprised at the magnitude of the variance but the instruments didn't lie.Wind direction and speed indications are bogus at best if the measuring instruments are mounted in poor locations subject to turbulence.  I have seen folks mount anemometers on rooftops and get really erroneous readings.  Wind vanes will point somewhere but not necessarily the wind direction away from aerodynamics disturbing impediments. Readings taken downwind of a structure (or trees, etc) need to be taken a minimum of 3 times the widest or tallest dimension of the obstruction from the obstruction and 7 times is better.  I know this is not good news for folks on moderate sized lots but you can't just ignore physics because it is inconvenient.  Personally, I'd like to be able to suspend gravity on demand but...Patrick        NJ5GOn 3/3/2019 12:54 PM, George Dubovsky wrote:> You pretty much have to avoid the house. As you surmise, even the North> side is going to be a heat source or sink. I did not start getting decent> readings - ones that compared to Wunderground, etc - until I moved mine to> a pagoda (homebrew, made from inverted, stacked dollar-store soup bowls)> 75' away from the house.>> 73,>> geo - n4ua>> On Sun, Mar 3, 2019 at 1:38 PM Gedas <w8bya at mchsi.com> wrote:>>> This made me wonder about sensor placement. I have had a number of>> different wx stations and the instructions most provide for the>> placement of the outdoor temperature sensor is to simply mount it on the>> north side of the house just under the eaves. This kind of makes sense>> as it will be away from direct sunlight but what about the heat from the>> house?>>>> How many do this and does it work for you? Do your temperature readings>> match those or come very close to an "official" local temp like at an>> airport.>>>> Has anyone else noticed just how critical the placement of this sensor>> really is? I have 2-3 outside sensors in different locations and they>> all read differently, sometimes as much as a 4F delta. I made sure they>> were all calibrated inside the house to read the same then installed>> them outside. Once the sun goes down my readings stabilize and my>> readings are within a degree of the "official" airport temperatures.>> During the day, esp summer time the readings can be all over the place.>>>> I know enough to keep them out of the sun, away from objects that can>> absorb & retain heat, off the ground at least 10' or so, not above>> concrete, etc......and yet I see big differences. So my question is>> where and how do people mount their temperature sensors?>>>> Also does anyone know where and how the "official" temperature sensors>> used by the NWS are mounted in places like airports?>>>> Gedas, W8BYA>>>> Gallery at http://w8bya.com>> Light travels faster than sound....>> This is why some people appear bright until you hear them speak.>>>> On 3/3/2019 1:19 PM, Michael Forinash wrote:>>> I bought a Davis Weather Station for my wife, who is a Weatherbird,>> seven years ago. As I recall, it was a six hundred dollar unit. In the past>> seven years, the only maintenance I have performed on it is remove a seed>> (from my neighbor’s tree) that blocks the flow of moisture through its>> self-emptying range gauge. It has a solar panel that recharges the unit’s>> rechargeable batteries. I have yet to change them.>>> The unit is attached to a twelve-foot pole.>>>>>> The installation instructions are a little vague on various points, but>> that’s the only criticism I can make of this package. Not a cheap station,>> but one my wife has been happy with, as the base unit sits on a end table>> by her chair in our living room. She checks the base station five or six>> times a day when she’s not monitoring the Weather Channel or the ND DOT>> online.>>> 73,>>> Mike>>> KB0RIA>>>>> _______________________________________________>>>>>>>> _______________________________________________>> TowerTalk mailing list>> TowerTalk at contesting.com>> http://lists.contesting.com/mailman/listinfo/towertalk>>> _______________________________________________>>>> _______________________________________________> TowerTalk mailing list> TowerTalk at contesting.com> http://lists.contesting.com/mailman/listinfo/towertalk______________________________________________________________________________________________TowerTalk mailing listTowerTalk at contesting.comhttp://lists.contesting.com/mailman/listinfo/towertalk