Abstract: A communications or radar radio receiver, of modified superheterodyne design, that will accept and process unknown radio frequency (R.F.) signals without the necessity of concurrent tuning of the R.F. stage(s) and adjustment of the local oscillator to a frequency proportional to the carrier frequency. The radio receiver employs a rotatable directional receiving antenna having adequate directivity indices to isolate and discriminate between adjacent signals in angular coordinates. When used in radar receiver applications in combination with an off-set frequency transponder, range and bearing can be obtained without resorting to a common specific frequency requirement for both radar and transponder. In such a case the servo of the radar receiver is used to position the antenna for detection of the carrier signal thereby providing an azimuth indication of the position of the unknown transmitter.

Abstract: A rear looking radar antenna system with a look angle of .+-. 120.degree. installed on a missile launching aircraft which has a conventional front looking antenna with a look-angle of .+-. 60.degree.. This permits a full 360.degree. to be covered. The search and track circuitry of the existing weapon control system is shared between the back and front antennas. As a target passes beyond the look-angle of one of the antennas, the other antenna picks it up. The weapon control circuitry is switched from the one to the other antenna at this time.