[danner]

Quick question. Is anyone else experiencing occasional wind gust spikes? I might be jumping the gun because I haven't had my FO wind up for that long, but so far I've seen three 25mph wind gust spikes out of nowhere when the other wind gusts are 11mph or so. And if I look on wunderground at stations near me none have any gusts that high.

Again I may be jumping to conclusions as I haven't had the FO wind up for very long, but I thought I would ask if there is something I might have done wrong to cause this? Or is this normal for FO wind gauges and I just need to upgrade them to make it go away?

I'm using CumulusMX running on a RPi3.

TIA

[werk_ag]

Hi,

I went to see the graphics of your station, and I'm not sure if those values around 25mph can be considered as spikes, or if they are simply gusts of wind, of very short duration. WeaherDuino can detect very short (3s) wind gusts.
Below is a graph from my own weather station, and you can see a very similar situation around 11:30 AM. Anemometer in use is an Inspeed VORTEX 8-Pulse High Resolution Anemometer

   

Not seems to me that there are anything wrong with your FO anemometer. However keep an eye on the readings.

[danner]

OK, thank you.

My ISP messed up my webspace so it is down until they fix it.

[tobyportugal]

Hello,

The winds is most difficult to compare with other stations.

I am to 35 km of Werk_AG:

[uncle_bob]

I am to 35 km of Werk_AG:

Hey, that's real handy for the new product release parties

[tobyportugal]

I am to 35 km of Werk_AG:

Hey, that's real handy for the new product release parties

And Paulo is with… 24 km!!
With Paulo (meteocaldas), we will assemble our WeatherDuino together.
Link Paulo: http://www.meteocaldas.com/pc/index.php
I apply the currency of Belgium: Unity is strength.

[danner]

I was looking over the cumulus FAQ and I noticed there is a "wind speed multiplier" and a "wind gust multiplier". Both of these I set to .448 as per the How To by Wizza. From the FAQ it looks like the wind speed multiplier is an offset to be used if your anemometer isn't 10m high. Mine is 5.5m high which corresponds to a multiplier of 1.12, but how does that work with the .448 that is already in there?

[werk_ag]

Little story about why with the WeatherDuino  you should use a 0.448 (or even 0.224) multiplier for wind speed and wind gust.

First, take at look at the user configurable settings on the RX software, there is a short explanation there.
Now the story: Davis weather stations measure wind just at 1mph resolution. WeatherDuino can do it a little better, and allows you to chose among three possible resolutions.
When you set this "#define VP2_WindRes" to 2 you get a resolution of 0.72Km/h (0.447mph), if you set that that value to 1, you get an even better resolution of 0.36Km/h(0.223mph), if you set it to 0 you get the standard Davis resolution of 1.62 Km/h (1mph).

So, as we are doing some trick with the Davis protocol, you also need to set on the weather software a multiplier, because it expects to receive values in mph.
This is why if you chose the standard Davis resolution, the multiplier should be 1, otherwise it should be set to the values described in the user configurable settings.
Please also note, that increasing the resolution will also decreases de maximum wind gust possible to be measured. Setting the resolution to 2 is a good compromise for most locations, with that value, the highest wind gust possible to be measured is 183.6 Km/h

Regarding any other adjustment to compensate for the height of the anemometer, I never tried that. In your case the value of 1.12 should be fine if you use the standard Davis resolution. My first impression is that just adding 0.12 to the 0.448 multiplier, will not give correct readings, perhaps something around 0.06 will work, but I'm not sure

[danner]

Thank you for the response. My ambient weather weather station is only 10ft off the ground so I put a 1.25 correction factor on that one to account for its height and wasn't sure where to do that on the WeatherDuino. But I understand now, the .448 is what is set in the Receiver. I'm happy with it's performance now so I'll just leave it alone. It is above my roof line, where the ambient weather is 8ft or so below the roof line, but exposed to the west, which is where the majority of our wind comes from.

I like the way the software averages the direction. That is much better than the other weather stations I've had that only plot the weaving back and forth of the vane.

[tobyportugal]

Hello Werk/Danner.

If you are a little patient , I can make a correct comparison of an anemometer Davis on a VP2 and WeatherDuino.
My anemometer is with 8.5m, it is easy to assemble another on a “L”.
I think that it is necessary to be careful with the corrections “software”. 1 + 1 must remain 2 and not 2.1
The same comparison on the UV-W/M2 would be also instructive.

Good weekend