GB760849A - Improvements in and relating to flexible electric conductors and cables - Google Patents

Abstract

760,849. Cables. TELEGRAPH CONSTRUCTION & MAINTENANCE CO., Ltd. June 6, 1955 [June 8, 1954], No. 16816/54. Class 36. In a flexible, high-frequency coaxial cable comprising an inner conductor, insulation and an outer conductor formed of braided or helically laid wires, the outer conductor is held to the insulation by a layer of a solid or grease-like compound having the same permittivity as the insulation, thus eliminating air spaces between the outer conductor and core due to displacement of the outer conductor on flexing. The compound may be applied as a tape into which the outer conductor wires will sink. Alternatively it may be applied by extrusion, either before or after the application of the outer conductor to the core. In either case the compound will be forced between and under the conductor wires, any surplus compound being removed from the outer surface of the conductor. The insulation may consist of polythene and the compound of a medium or soft grade polythene, a polyisobutylene-based material or mixtures of polyisobutylene or butyl rubber with other elastomeric or thermoplastic resin such as polystyrene or gutta-percha hydrocarbons. The insulation may alternatively consist of polytetrafluoroethylene and the compound of a silicone elastomer, polytetrafluorethylene or polychlorofluoro hydrocarbons of low molecular weight.