Direction finder

In a direction finder including a directional X-axis antenna having a directional sensitivity pattern in the direction of the X-axis of Cartesian co-ordinates and a directional Y-axis antenna having a directional sensitivity pattern in the direction of the Y-axis thereof and a non-directional antenna, said direction finder comprising means separately combining the voltage signals induced in each of the directional X-axis and Y-axis antenna and the voltage signals induced in the non-directional antenna to obtain combined voltage signals respectively corresponding to the directional X-axis and Y-axis antennas, said direction finder further comprising means for producing X-axis and Y-axis component signals from the rectified and amplified combined voltage signals and the voltage signals induced in the non-directional antenna, and means for indicating the direction determined by a vector addition of the X-axis and Y-axis component signals as the bearing of a source of incoming signals, the improvement wherein the combining means comprises

• signal generating means for combining and rectifying the voltage signals induced in one of the directional antennas and the ones induced in the non-directional antenna to obtain rectified positive phase and negative phase combined voltage signals with a phase relationship of 180.degree. apart to each other for each of the directive X-axis and Y-axis antennas,
• said direction finder further comprising selecting means for appropriately selecting the rectified positive phase or negative phase combined voltage signals within an azimuth range wherein the magnitude of the rectified positive and negative phase combined voltage signals varies in a distorted manner with respect to sine or cosine curves depending on the change of the bearing of the source of incoming signals.