Topic: Question about anemometer

[MchWxEnthusiast]

How can I tune my anemometer to get the most accurate wind speeds? I mean loosening worked but I don't know how sensitive to make it, I wish I could buy a handheld PWS to calibrate it but I ain't got no money right now so what do I do?

[92merc]

Just keep it clean of bird poo, bug webs.  Have it in a spot best suited for wind, not being blocked.

I had almost a million miles on my VP2 from 2008 before the anemometer siezed up.  I did nothing to it.  Bearings were wore out.

[Mattk]

There is not much one can do in that regard, not with standard Davis software anyway. Unless the anemometer is sited properly then there will always be some unknown variables that can bot be accounted for. Thinking of trying to calibrate against a handheld PWS isn't a viable option.   

[MchWxEnthusiast]

Does anyone atleast know how to fine tune it enough to get it the most accurate readings? Like how much to loosen it? I'm not putting anything on the roof because of my fear and i'm not paying someone to do it. I know my station is currently in a bad spot, but I am planning to move it when I get one of those tripods for it since my yard is too small.

[Mattk]

Can you explain what you mean by "loosen it"? Loosen what?

[MchWxEnthusiast]

The part where that fastens the cups to the rest of the anemometer. Sorry if I wasn't specific, I keep forgetting!

[Mattk]

The part where that fastens the cups to the rest of the anemometer. Sorry if I wasn't specific, I keep forgetting!

If you loosen them to much then they could fall off, they need to be secured properly.

[CW2274]

The part where that fastens the cups to the rest of the anemometer. Sorry if I wasn't specific, I keep forgetting!

The design keeps the cups from binding to the housing. You're accomplishing nothing other than giving yourself a headache.

[weatherdoc]

It depends what you mean by accurate.

Assuming the anemometer is maintained as it came from the factory, it's as accurate as it can be, performing to Davis' specifications.

Siting is a different issue. Most of us can't site our anemometer at 10 m (~30 ft) above ground and away from most obstructions unless we have a large piece of property with no trees. Even on a roof top, there are issues. That said, the wind speed is what it is where you are measuring it and your wind speed will likely be less than your closest airport with an ASOS or AWOS "out in the open". Think about the purpose of your anemometer. One project the FAA is working on is providing weather parameters for UAS for operations Beyond Visual Line of Site (BVLOS). Say a drone is delivering a package in your neighborhood. The winds at the nearest airport are not representative of your neighborhood with building and trees affecting wind flow but home weather stations are representative and most that are internet connected are included NOAA's MADIS data set. Those MADIS observations help create NOAA products including the Helicopter Emergency Medical Services (HEMS) tool and Real Time Mesoscale Analysis (RTMA) - both used by the UAS community for low-level flight where there are no "official" observations.

In my opinion, site it as best you can and don't mess with the hardware except to keep it clean!

[TheBushPilot]

There's not so much tuning as there is maintenance and calibration. Given the anemometer has a predetermined design that cannot be changed, your best bet is to perform preventative maintenance and calibration as desired.

Scheduled maintenance regardless of interval is an important aspect of instrument sensitivity. Things as simple as cleaning and bearing replacement all contribute to maintaining performance and longevity of the anemometer. The sensor will perform intended so long as nothing catastrophically fails within it.

Calibration is another supplementary tool for assuring accuracy. I say supplementary because it's not necessary for operation but a helpful verification report. Davis Instruments offers NIST Traceable calibration of their anemometers for $150. The service is pricey but will guarantee your anemometer is working within specification without doubt.

And like others have stated, siting is also crucial in ensuring correct measurements. While often times it isn't feasible to mount the anemometer 10m AGL, getting it as high as possible and as far from obstruction as possible is often times better than nothing.

Cheers