Had a strange one today. Went to use the Kestrel and whenever the unit was vertically oriented (right side up or upside down), it would read 7.5 mph on the wind gauge when the prop wasn't moving. If the unit was held horizontally, either to the right or left with the prop not moving, it would read 0 mph. Hmm... Went to Nielsen Kellermen (company that makes Kestrel) customer support and dialed the number, selecting tech. support: Support for NK Electronics for Rowing and Kestrel Wind Meters - Nielsen Kellerman Talked to a guy there that said I could try a 'hard reset' (perhaps this is in the instructions...not sure where mine are). Take out the battery and hold the button on the right for at least 30 seconds. This is supposed to 'drain' whatever stored energy there may be in the unit, separate from the battery. At any rate, do this worked. The unit now reads 0 mph at any orientation with the prop not moving. New one to me... Perhaps this'll help someone else.