A vertical antenna made of transposed sections of coaxial cable

A vertical array of colinear vertical dipoles is made of a series of sections of solid-dielectric coaxial cable with their inner and outer conductors transposed at each junction. Each section has an effective length of 1/2 wavelength in the cable, so the radiating gaps between the sections are all excited in the same polarity. A model designed for 450 Mc has 9 sections of cable; the length is 2.9 wavelengths in free space and the gain is 6 db over a half-wave dipole. This type of antenna has been developed in cooperation with Communication Products Company of Marlboro, N.J.