Vantage Pro 2 Anemometer

[STHirsch]

What should the cup size be set to on the Vantage Pro 2 console for the Anemometer?

Thanks

Steve

[steve]

The normal one (since about 2000) is 'large'. Small cups are an option for those in areas with very high wind speeds.

[STHirsch]

Thanks for the fast reply. That is what I have it set to. I run the Vantage Pro 2 side by side on the same mast with a WS-2080 which always gives me a higher reading. Any ideas??

Thanks

[steve]

They measure wind differently. The Davis effectively gives an average over about 2.5 seconds (you can also get the console to display a 10-minute average along the bottom of the display). The Fine Offset station measures speeds averaged over 2-second periods and then supplies two values every 48 seconds: one is the highest of the 24 2-second readings (which it displays as 'gust'), and the other is the average of the 24 readings. So I'd expect to see differences between the two.

If you take the 10-minute average of the average values from the Fine Offset (which you can get Cumulus to display, with the appropriate settings) and compare it with the 10-minute average from the Davis console (or as calculated by Cumulus), then you might expect them to be similar; and if they're not, I would put that down to the Davis being more accurate, all other things being equal.

[STHirsch]

Makes sense thanks!!