Abstract: A monopole antenna is mounted on a ground plane and incorporates a radiating structure such as a disc or hollow cap parallel to the ground plane, for loading the antenna. An elevated feed is formed by a biconical central post between the radiating structure and the ground plane. Tuning is also accomplished by a partial or total circumferential dielectric (which may also function as a support) having an outer electrically conducting sheet spaced apart from the central post to provide shunt capacitance, and by outboard inductive posts which connect between the ground plane and the radiating structure to provide shunt inductance. Alternatively, additional tuning may be accomplished by a circuit between the upper and lower portions of the central post.

Abstract: Two or mutually nonparallel dipoles for operation over a common frequency band. Each of the dipoles has a central feed port and an inner end connected to a junction box with conductive walls. Each feed port is connected through a junction in the box to a receiver for the common frequency band. For diversity, two receivers for the common frequency band are connected to the two feed ports. For pseudodiversity, the dipoles are connected to a common receiver and are positioned to have noncoincident phase centers separated by more than one-quarter wavelength over some part of the common frequency band.

Abstract: An antenna system having an array of radiating elements arranged in element modules is provided with coupling networks, one associated with each element module, each network having an input port. Each coupling network provides coupling between its input port and elements in the associated element module, as well as independent coupling between its input port and selected elements associated with other modules in the array.

Abstract: A processing apparatus for determining the frequency of a supplied signal is usable in a Doppler microwave landing system. The apparatus derives scalar signals representative of signal frequency and amplitude and computes the average value of the scalar signals over a number of time intervals prior to dividing the signals to produce an output signal representative of average supplied signal frequency.

Abstract: 1. A method of radio transmission comprising radiating electromagnetic waves in the earth's crust through a "deep wave guide" formed of basement rock bounded on its upper side by a surface layer of sufficient conductivity to form the upper boundary of the wave guide and bounded on its lower side by a region having a temperature of several hundred degrees Centigrade, which temperature causes the lower region to have a conductivity which is high relative to that of the basement rock.