Goniometer

As used in radio frequency (RF) antenna systems, a direction-sensing device consisting of two fixed loops of wire oriented 90circ from each other, which separately sense received signal strength and send those signals to two rotors (also oriented 90circ) in the sealed direction-indicating instrument. The rotors are attached to the direction-indicating needle of the instrument and rotated by a small motor until minimum magnetic field is sensed near the rotors