Could be there just isn't enough wind when you are watching.
Over-estimated wind speed was a big problem for me in the beginning.
Here, 15MPH is some Serious Wind at the levels I have to work with. It's rare my anemometer reads above 8MPH, unless the forcast calls for over 20MPH.
Might be able to sign one out of the physics lab?
Call the local Radio Shacks, ask if they have part number 63-1119. Probably sold them out 2 years ago, but worth a shot.