Abstract: In accordance with the present invention, a single shunt feed mechanism, including a single gamma section and a single impedance matching circuit, is employed to enable an antenna tower as an effective radiator in plural wave length bands without having to alter the upper tie point of the gamma section to the antenna tower. In one embodiment, the shunt feed of the invention enables the antenna tower as an effective radiator in either two of the adjacent bands mentioned, namely the 40 and 80 meter bands or the 80 and 160 meter bands. In accordance with another embodiment of the invention, a single shunt feed mechanism, including a single gamma section, a single impedance matching circuit, and a filter, enables an antenna tower as an effective radiator in all three of the indicated bands.

Abstract: A portable multiband H.F. antenna that has minimum ground area requirements and that is capable of transmitting electromagnetic wave radiation with horizontal polarization, azimuth plane omnidirectional patterns and a null in the vertical beam pattern is realized by means of an easily erectable tower type radiator. The tower structure has adjacent conductive leg members that define an elongated antenna slot aperture the total length of which is resonant to the lowest operating frequency band. A microwave transmission line resides along one side of the slot and the slot aperture is fed by shorting the transmission line to the oposite side of the slot. Operation at higher frequency bands is achieved by shorting out sections of the slot aperture on both sides of the feed. An array of radiating slot apertures can be provided by shorting the full slot aperture into sections and feeding each slot section separately.

Abstract: A method and preferred apparatus for introducing radio frequency isolation near the base of a conductive tower to prevent significant flow of RF current into the ground, thereby to produce an elevated vertical antenna. The invention further relates to a method and apparatus for introducing RF power into the upper portion of the isolated tower to cause said portion to radiate or receive at desired frequencies. Isolation and "excitation" are accomplished by the placement of tuned shortened quarter wave conductive sections along selected portions of the tower, the quarter wave sections used for antenna excitation being also used for impedance transformation to match a coaxial transmission line of nominal inmpedance.

Abstract: A base station radio antenna comprising a bracket having a first section for attachment to a support structure and a second section for receiving antenna whips, an antenna whip extending upwardly from a central opening in the second section of the bracket, and a plurality of antenna whips inclined relative to the upwardly extending antenna whip and extending generally downwardly from openings in the second section spaced radially from, and equi-angularly around, the central opening.

Abstract: A relatively low frequency linear element antenna characterized by its lightweight construction, relatively wide band width, and elastic strain energy deployment capability. The antenna has a plurality of slender electrical conductors such as wires forming radiating elements secured to a supporting tube with the conductors extending lengthwise of and spaced about the tube wall and electrically joined at the base end of the tube in such a way that the antenna has the same radiation characteristic as a conventional cylindrical antenna of the same diameter as the tube. The base ends of the conductors are gathered for connection to the center conductor of a coaxial antenna feed line to provide an impedance match between the antenna and coaxial line. The antenna supporting tube may comprise a thin-walled, resiliently flexible, strain energy deployable tube to permit contraction of the antenna to a folded or coiled packaged configuration and antenna deployment by elastic strain energy stored in the contracted tube.

Abstract: A base insulator design for VLF antennas. A surface insulating material, h as glass, serves to provide a long surface distance between the upper and lower metallic components of the base. A thin, soft metal cover extends the base metal conductor out to the edge of the outer insulator and also provides a weather shield for the internal components. An insulator core of porcelain serves to take up all of the mechanical stress in the structure and a dielectric fluid serves as a coolant which also protects the inside surface from contamination.

Abstract: Protection against the Corona effect is obtained, at the junction between a conductor cable and an insulating cable, by means of loops at an acute angle with the insulating cable, these loops being made of conductor elements clamped in the fixing means, and at least one of the loops being formed by the conductor cable itself.