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Author Topic: Different Levels of anemometer heights  (Read 1719 times)

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Offline aardvark

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Different Levels of anemometer heights
« on: November 10, 2013, 04:49:45 PM »
i have two anemometers.   I am noticing a difference that I originally thought might be due to the trees around the lot.  The one at the bottom rotates more often than the one at the top.    Both do send signals when I compare them, however it is curious why the one closer to the ground works more often.

The mast is heavy and to take down the junk attached plus the six guy wires and all that , would be really tough as I am much older than when Iput it up.

one theory I have is that maybe the unit is tipped a bit on the top, looser over time and shifted,  the other, is the POT is old and just doesn't turn as easily, a third is that the differences between the trees where there is leaf blocking the flow, so the trees are blocking the wind and the space below the trees move the lower one.  just a thought.  The picture is old as I have taken off the passive shield, just haven't bothered to update the photo.

I can switch between the two anemometers from the house, one is on the wireless anemometer transmitter, the top one is hooked to the ISS.  I originally put both in because  it freezes in the winter and the lower one is easier to dislodge and in case the top one died out or the bottom one, I could use a backup.
Davis VP2 Plus; 24h  FARS; Extra Temp Humid sensor (2); Extra Temp Station (2); Soil Moisture/Temp Station;Weatherlink IP;USB; MAC Mojave;https://www.weatherlink.com/embeddablePage/show/1c484adbfa914d1aa10a58ad53ccd563/summary

Offline NorCal Dan

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Re: Different Levels of anemometer heights
« Reply #1 on: November 10, 2013, 08:55:18 PM »
Depending on what the exact readings are on both anemometers at the same time, it could be turbulence or the Bernoulli effect. 

Offline aardvark

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Re: Different Levels of anemometer heights
« Reply #2 on: November 10, 2013, 11:18:27 PM »
the bottom one always moves, but the top one, sometimes, and displays different wind directions.   Could be as you say.  I have no intent on putting anything up on our roof.  I am too old to climb up there, besides it is steel surface and it doesn't grip the shoes like shingle.

Anyway, I do live on the ground and it is not that important.   
Davis VP2 Plus; 24h  FARS; Extra Temp Humid sensor (2); Extra Temp Station (2); Soil Moisture/Temp Station;Weatherlink IP;USB; MAC Mojave;https://www.weatherlink.com/embeddablePage/show/1c484adbfa914d1aa10a58ad53ccd563/summary

 

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