I just rebuilt the Datamarine LX360Q wind direction/speed masthead unit with the rebuild kit from DMI Marine. There have been no problems with the direction indicator, but the speed I believe is not correct. It appears to me that the cups on the masthead unit are spinning much slower than they should be given the wind speeds. I have a friend that has loaned me a high-quality anemometer and I'm planning on going up the mast to see if I can figure out how to calibrate this unit. Since the thought process usually isn't as good when you're hanging in a bosun's chair 50' up, does anybody know how this is actually done so that I know what I'm doing when I get up there??? Thanks. Jim