Having a problem with my Davis anemometer. The speed is showing ok but not the direction, it "snaps to north." Am I right in thinking this is a short circuit somewhere caused by damage to the cable or is it worth checking the tightening screw on the wind vane (which means taking the flipping pole down lol)?
Sorry for the late reply...
The direction shows N if there is a break in the cable. It does that because the (intentional) gap in the potentiometer track inside the anemometer head is at N, hence so far as the base unit is concerned a break indicates N.
This means that it also shows N if a gap has worn in the potentiometer track, but that isn't a continuous thing it just means that you get a N instead of the real direction if the vane is directly over the worn spot.
I've had a potentiometer fault happen twice now & each time the Davis was reporting N when the vane was around WSW (our prevailing direction) till it was fixed. The fix on both occasions was to replace the potentiometer (first time I had the anemometer repaired, second time I bought a new anemometer so that I now have one to put up while the other is being repaired if it happens again...).
