Topic: Wind Vane Sensitivity

[A1cntrler]

Has anyone come up with a solution that will help to steady the wind vane?  It seems as if the AcuRite 5-in-1 vane is hyper sensitive.  Not only does my data support this, but just by standing outside and watching it on a calm day the slightest breath of wind will spin it around in a circle:

http://www.wunderground.com/personal-weather-station/dashboard?ID=KCAMOORP12

A couple of weeks ago I got my brother to set up a station at his house in Virginia.  He went with an Ambient station and looking at his wind direction readings on the chart makes more sense than my AcuRite:

http://www.wunderground.com/personal-weather-station/dashboard?ID=Kvaspots14

Would adding a bit of weight to the tail or the head of the AcuRite sensor help to steady it up? 

[nincehelser]

Has anyone come up with a solution that will help to steady the wind vane?  It seems as if the AcuRite 5-in-1 vane is hyper sensitive.  Not only does my data support this, but just by standing outside and watching it on a calm day the slightest breath of wind will spin it around in a circle:

http://www.wunderground.com/personal-weather-station/dashboard?ID=KCAMOORP12

A couple of weeks ago I got my brother to set up a station at his house in Virginia.  He went with an Ambient station and looking at his wind direction readings on the chart makes more sense than my AcuRite:

http://www.wunderground.com/personal-weather-station/dashboard?ID=Kvaspots14

Would adding a bit of weight to the tail or the head of the AcuRite sensor help to steady it up?

That's actually the way it's supposed to be.  Your software shouldn't be reporting a wind direction below 1 mph. 

If it really bothers you, you can add a bit more "tail" with a few short strands of yarn affixed to the tail.  A bit of duct tape can also work as extra tail.

If you want to add weight, it should be toward the head end. 

[A1cntrler]

That's actually the way it's supposed to be.  Your software shouldn't be reporting a wind direction below 1 mph.

I can see several instances throughout the day in today's data where there is a 0mph reading yet it is still showing data for the direction.  Is there a setting somewhere I missed in my Meteobridge or it is just a programming issue where it is recorded regardless of wind speed?

[nincehelser]

That's actually the way it's supposed to be.  Your software shouldn't be reporting a wind direction below 1 mph.

I can see several instances throughout the day in today's data where there is a 0mph reading yet it is still showing data for the direction.  Is there a setting somewhere I missed in my Meteobridge or it is just a programming issue where it is recorded regardless of wind speed?

I don't know about Meteobridge settings.  The lowest non-zero wind speed the 5n1 puts out is 1 mph.  A direction for 0 speed doesn't make a lot of sense.  Somehow some software manages to get wunderground to display "calm" entries in the table, but I haven't figured out how to do that myself.

[miraculon]

How is the station sited? Maybe you are getting eddy currents from your roof. I have seen badly behaving wind vanes where they are being affected by wind currents around and over the roof. Is your station clear of the roof? Maybe if you posted a photo, we could see if there is a problem with the installation that might be causing some of this.

For what it's worth, I thought that my Davis vane had a lot of drag, but the feedback that I got at the time was this helps eliminate some of these variable wind issues. It would be difficult to retrofit the bearings on your Acu-Rite, so maybe some of these tricks mentioned might help for a while. It would be interesting to see how long they hold up though!

Greg H.

[DoctorKnow]

The wind vane drove me nuts for a while, but I guess I just got used to it flopping all over the place. String did nothing for me. It needs some serious weight, but I gave up on it.

[A1cntrler]

How is the station sited? Maybe you are getting eddy currents from your roof. I have seen badly behaving wind vanes where they are being affected by wind currents around and over the roof.
Greg H.

While entirely possible, I think this is more an AcuRite Pro Weather center (5-in-1) issue.  As I click around of other stations on WU, I can tell by the wind direction data if it's a AcuRite Pro or not.  Here are a few I saw today from various places across the country:

http://www.wunderground.com/personal-weather-station/dashboard?ID=KVASPOTS6

http://www.wunderground.com/personal-weather-station/dashboard?ID=KNESEWAR7

http://www.wunderground.com/personal-weather-station/dashboard?ID=KNESEWAR6

http://www.wunderground.com/personal-weather-station/dashboard?ID=KUTCASTL5

All of the above sites report the erratic wind direction.  As I clicked my way across the country looking at the wind data, as soon as I see the history for the day and the plotting of the data I could tell whether or not the station was an AcuRite station or not before I even clicked on the "About PWS" to confirm

While siting could be an issue in each of these, my method for finding them was rather random (clicking on the map and checking stations).  Most had fairly linear plots of the data indicating a general direction in which the wind comes from.  But the AcuRite data is rather random and all over the place. 

While my data is reported more often than most (Meteobridge reports for me) even those that broadcast to WU through AcuRite looked the same.

[nincehelser]

Some people prefer sensitivity, others prefer what they think are pretty graphs.

The vane is designed to have very low resistance.  It's supposed to turn easily.  If a 1 MPH wind isn't able to turn it, then it would be inaccurate.  For anything less then 1 MPH the direction should be disregarded.

Heck, if you really want really "smooth" graphs, reduce the tail area considerably.  Then it will tend to "stick" the last place a good wind turned it, but it will be unaffected by lesser winds.  It won't be terribly accurate, though.

[pcjunky]

We had almost an hour of calm winds yesterday and I noticed the wind speed was 0 but the wind direction would sometimes change from SSE to S and back to SSE.  Nothing major.  It's not like it was swinging back and forth or making huge direction changes.

From what I can tell the 5in1 reads the wind speed in kph and the PC Connect software converts it to mph when you download the history.  I'm not sure why 0.6mph or 1 kph doesn't show up in my history, but I got readings from 1.2 mph to 14.9 mph which convert 2 kph to 24 kph.  Above that my readings are spotty and I had some readings over 60 mph which I assume were bogus.

Anyway I thought this might explain why the wind wane moves even though the mph on the display is < 1.

[nincehelser]

The wind direction transmits every 36 seconds regardless of the wind speed (which updates every 18 seconds).  The lowest non-zero wind speed that will be reported by the hardware is about 1mph.  (the 5n1 does send data in metric, so there's a little bit of conversion error)

So basically if there is a zero wind reading, the vane might still be moving around.  When it comes time to report direction, it gives one as a hex digit, representing 1 of the 16 direction on a compass rose.  The hardware isn't "smart" enough to report a "null" direction, so it's up to software to decide whether to report a direction or not.

[DoctorKnow]

I'll share what I did since this was brought up again. I took a piece of metal, in the shape of a rectangle, cut so it would have clearance to pass under the sensor as the vane goes around, and drilled a hole in the center the size of the vane nose, and slipped it on the front of the vane nose. Now my vane has stopped flopping some. You might could use some metal or rubber washers also.

[Cutty Sark Sailor]

Miraculon spoke correctly.  How is the siting of the Vane/anemometer? And is it level?  For example, there's, among other things, something called the "Urban Boundary Layer", where nearby rooftops create their own wind patterns, which change, gust, rapidly,... there are other things involved with accurate, or semi-accurate wind indications.... also.... Too Sensitive?  Doubt it....


How to find it?  Helium balloon with a long piece of string... Eyeballs Mark I.... you heard it here.... 
Mike

[DoctorKnow]

If you saw some of the trees that I have around, you would understand that it is impossible to get above them. It is very difficult to site the instrument, there is no question of that, but when you live with houses and trees you do the best you can. Sometimes you have to improvise, and that is what I did and it has helped me, now whether it will work for everyone is doubtful. When you have swirling winds, and an ultra sensitive vain, you are really in for a challenge, and adding some weight to the vane will help to settle it down some. It is very loose and light.

[Cutty Sark Sailor]

@Doctor KNow:
I've no question you've adapted to your situation, as I've adapted to mine... However... to restructure or modify a device is begging the question of accuracy. It's trying to report what it senses at its location.  Since the original poster did not describe location and mounting, I felt it necessary to mention something very simple, that lots of folks in urban areas may not be aware of.  There are very specific specs given for wind measurements, which few of us can resolve without 'mods' either in software adjustments, whatever.  Glad you've resolved yours.... We do the best we can with our environment, as you've done. Good Job, if it works for you!

Mike

[A1cntrler]

How is the siting of the Vane/anemometer? And is it level?

Thank you for the input.  My gauge is about 30ft off the ground, about 6 ft higher than my roof.  It is attached to my chimney and the bubble level in it is right ont eh mark..   I suppose it is possible that it is just hyper bouncy from some errant wind currents, but it seems that most people with the AcuRite units, while they might not notice it as much as I do, suffer from the same issue.  Just in my random sampling of WU data for other 5-in-1 units the data shows nearly the same across all of them.  The design of the unit is kind of odd though in that the Wind Vane is situated under the unit right behind a 1 inch pole that it mounts to.  Has got to cause some sort of turbulence as well.

[haroldashe]

I slid a small, light metal washer over the nose piece of the vane and that did "calm it down" somewhat.  It still swings around easily in the slightest breeze.

[sundevil01010101]

Hey Cutty Sark Sailor,

I love the height you have on that tripod mount but how in the world are you changing batteries, cherry picker?

How high is that?  Mine is like 15.85' but yours looks like 25-30 ft?

[W4JTB]

I see there hasn't been a comment here in a while, but wanted to let everyone know that a metal washer on the nose did the trick for me. It's still sensitive which we want, but it's not all over the place anymore.

[daman]

My old system was a Lacrosse and this new 5n1 definitely floats around more, the Lacrosse had a big and heavier wind vain witch kept it more stable but very accurate, this 5n1 moves around like a feather in a hurricane, bad design!!

[nincehelser]

My old system was a Lacrosse and this new 5n1 definitely floats around more, the Lacrosse had a big and heavier wind vain witch kept it more stable but very accurate, this 5n1 moves around like a feather in a hurricane, bad design!!

Better to be too sensitive than not sensitive enough.

It's designed to have low resistance to movement.  That's why it uses an optical encoder.

[DoctorKnow]

I see there hasn't been a comment here in a while, but wanted to let everyone know that a metal washer on the nose did the trick for me. It's still sensitive which we want, but it's not all over the place anymore.

It stops the swirling, which is the biggest problem. A little sway I think we can live with.

[DoctorKnow]

My old system was a Lacrosse and this new 5n1 definitely floats around more, the Lacrosse had a big and heavier wind vain witch kept it more stable but very accurate, this 5n1 moves around like a feather in a hurricane, bad design!!

Better to be too sensitive than not sensitive enough.

It's designed to have low resistance to movement.  That's why it uses an optical encoder.

One is just as bad as the other. It leaves the vane useless when all you see on historical data is a mess of dots all over the place.

[nincehelser]

One is just as bad as the other. It leaves the vane useless when all you see on historical data is a mess of dots all over the place.

No. 

If you feel you have "dots all over the place", you can simply deaden the response, either physically or through software.

You can't go the other way, though.

This thread started with someone who didn't like the "slightest breath of wind" turning the vane.  As I've mentioned before, wind direction at very slow wind speeds, particularly one that is registering as zero, is not meaningful.

[Inverno]

One big problem with arguing this is a lot of people do not have the ability to properly site their weather station, so the winds going in a bunch of directions is normal.  Mine is 20 feet from my house surrounded by trees/house on 3 sides...but I make due with what I have.  My father put up a weather station in their large yard at a good height, free from any structures or trees, and his wind data was awesome.  If the forecast said wind from the NE, his station reported it spot on etc.  Looking at George's station, his wind data is very good as well.  I believe his his sited in an open field as well.

[haroldashe]

Yep, you got it.