Investigation of a surface-wave line for long distance transmission

The surface-wave line discussed in this paper is a single conductor with a dielectric coat. The energy is propagated along the surface of the line in a wave mode similar to that in a coaxial line. The phase velocity of this wave is reduced by 1 to 5% from the velocity of light, depending on the thickness of' the dielectric layer. Because of this reduction in phase velocity, no outer conductor is necessary for the return of the current. The conduction current in the outer conductor of a coaxial line is replaced by a displacement current through the air. The experiments demonstrated that the single conductor surface-wave transmission line is practical for long-distance, wide-band communication. They also indicated possible improvements: (a) The use of "copperweld" conductor rather than a conductor with segmental structure in order to reduce the conductivity loss. The ~eat mechanical strength of this cable would permit an increase in the span to at least 250 feet; (b) Avoiding unnecessary curves; (o) Omitting the· messenger wire..