US Government As Represented by the Secretary of the Army

Palemon W Dubowicz

Donn V Campbell

Felix Schwering

Kenneth J Loffer

Bernard E Feigenbaum

Steve R Goodall

Robert T Hoverter

A plurality of dual feed half square wave antenna element (each of U-shaped onfiguration) are arranged in a log-periodic structure. The antenna elements are feed at the current loops; i.e., at the corners of the U-shaped antenna elements. A dual inphase feed produces vertical polarization signals of low angle radiation, and a dual antiphase feed produces horizontal polarization signals of high angle radiation.

Log - periodic HF antenna system

Two cosited omnidirectional biconical antennas are respectively tilted plus nd minus 45 degrees (.+-.45.degree.) with respect to the vertical and, therefore, are perpendicular (90.degree.) with respect to each other to effect polarization mismatch and near field decoupling. In combination with the described antennae orientation, high impedance cable chokes are added in series with the coaxial cable antennae feed lines to suppress induced parasitic rf currents.

Highly decoupled cosited antennas

A vertically polarized array comprised of both bottom fed and top fed conurations having a driven element comprising at least one but, when desirable, two generally horizontal wire conductor segments of a length substantially equal to one half the operating wavelength of the array and with the ends of the half-wave conductor segments being connected to or extending into generally vertical quarter wavelength wire conductor segments. In a bottom fed configuration the feedpoint is at the bottom end of one vertical quarter wavelength conductor segment while in a top fed configuration one vertical quarter wavelength segment comprises a quarter wavelength of coaxial transmission line having one end configured into signal isolation means, comprising a cable choke, while the feedpoint is located at the other end. Behind the array, located at a distance of substantially a quarter wavelength, is a parasitic reflector element comprising a substantially identical structure as the driven element with the lower ends of the vertical quarter wavelength elements thereof positioned a foot or two above the surface of the ground. Such an arrangement provides unidirectional radiation and reception at low take-off angles, e.g. 20.degree. above the horizon.

Tactical high frequency array antennas

A termination for a VHF inverted-V half-rhombic antenna is described, consisting of a transformer terminated into a length of high attenuation coaxial cable acting as a power dissipation line.

Coaxial power dissipation line

A high voltage protection device for protecting personnel from injury or th as well as damage to radios and vehicles when a whip antenna comes in contact with overhead high voltage power lines or the like and comprises a high voltage coaxial capacitance device which is coupled in series between the upper and lower section of a whip antenna. The capacitive reactance of the capacitance device is very high at power line frequencies and relatively low at RF frequencies. The capacitance element is comprised of two concentric cylindrical conductors formed in a fiberglass shell and separated from one another by a dielectric such as polytetra fluorethylene.

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Eatontown, NJ, United States of America

Palemon W Dubowicz