A direction finding system for finding the angle of arrival of a target signal from a transmitter. The system includes a plurality of directional antennas positioned to face different directions for receiving the target signal. The antennas are mounted as an antenna array on a rotatable mount for supporting and rotating the antenna array. A receiver unit down converts the RF target signal to IF signals that are digitized by an A/D converter providing digital values. A computer computes the power in the signals from the A/D samples. A computer stores calibration information for the directional antennas, processes the digital values and the calibration information to determine a rotation angle α for rotating the antennas to provide new digital values, processes the new digital values and the calibration information to determine an intersection angle, and subtracts the rotation angle from the intersection angle to determine the final value for the angle of arrival of the target signal.