Abstract: A covert line of sight time division multiple access communications system omprised of a plurality of geographically separated transceivers consisting of identical hardware and capable of operating either as a master station or a slave station, and when desirable as a repeater station. The system operates with a non-committed master station operating within a predetermined power circle of operation whereby multiple slave stations and/or repeaters communicate with each other by way of the master station in a one half duplex mode at a single frequency in the millimeter wave frequency range between 54 and 58 GHz.

Abstract: To reduce guidance errors in a microwave landing system from false signals eflected by objects along runways, the transmitting antenna radiates an elliptically polarized beam. At the airborne receiver an antenna, such as a pyramidal horn, maintains the separation of the horizontal and vertical components. These components are separated and then split on an equal power basis. One part of the vertical field component is shifted by 90 degrees and added to one part of the horizontal component in a detector, whose output is in effect like that of a circularly polarized receiver. The other parts of the horizontal and vertical components are separately detected. The outputs of the three detectors are combined in a multiplier, to yield a resultant output. For a very broad angular distribution the undesired reflected signals are strongly attenuated.