Coil reacts to movement

[Batonas]

I built my second DD coil for quasar arm and both of them have the same problem, that there is false reaction to fast movement. First thought was that it is due to lack of physical rigidity, but coil is made in thermoformed 3mm abs plastic housing, filled with pure epoxy and fiberglass. Can't imagine it being any stronger. Is there a possibility the issue is with the device itself or incorrect settings maybe? Do not yet have a commercial coil or circuit to test it with. Problem still exists outdoors.

[waltr]

Does the detector circuit have a way to eliminate Earth field effects (current produced by moving a coil through a magnetic field)