ANTENNA SYSTEM FOR VHF AND UHF RADIO DIRECTION FINDERS

摘要

An antenna system for a VHF and UHF radio direction finder comprises a loop antenna formed by turns which are arranged on an elongated magnetodielectric core. The antenna system has also an omnidirectional antenna member and a switch means which shapes the resultant directivity pattern by adding up signals from the loop and omnidirectional antennas and changing the position of this pattern discretely by 180 DEG in the horizontal plane to obtain its mirror image. The omnidirectional antenna is made in the form of a closed turn arranged on the core of the loop antenna so that it is substantially perpendicular to the turns of the loop antenna. A portion of the closed turn is disposed in the direction of the longitudinal axis of the core is elevated above the core surface through a known distance whereby the magnitude of the signal from the omnidirectional antenna is such that the two resultant directivity patterns of the antenna system intersect only at two points in a horizontal plane.