Method of Installing Fire Resistant Coaxial Cable for Distributed Antenna Systems

Abstract

A method of installing a fire resistant coaxial cable is described in which the cable has a 2-part dielectric made of a polymer foam and a ceramifiable silicone rubber. The polymer foam, which can be polypropylene or other polymers, leaves little-to-no residue in the cable that causes electromagnetic loss when upon burning. The polymer foam can be extruded over a center conductor using an inert gas, such as nitrogen, to propagate the foam, ensuring little-to-no residue in the cable. The ceramifiable silicone rubber can be extruded over the polymer foam. The cable is configured to maintain a relatively coaxial relation between a center conductor and an outer conductor even under aforementioned fire tests. Another layer of ceramifiable silicone rubber can surround the outer conductor and continue to insulate it from the outside if a low-smoke zero-halogen (LSZH) jacket outer layer burns away.

Dependencies are inferred from the claim text.