Electrical and mechanical characteristics of the styroflex-helix coaxial cable

A type of coaxial cable with an air dielectric and aluminum outer conductor which has been in use in Europe since 1948 up to about 200 mc., has been found by recent measurements to be highly efficient in the range 1,000 to 10,000 mc. The cable consists of an inner conductor of copper around which a helical spacer has been built up of polystyrene tapes 2 to 6 mils in thickness, the spacer being covered with an insulating sheath consisting of two layers of polystyrene tape 1 inch or more in width, and over this is the outer conductor of aluminum. The helix occupies in present designs 10 to 12 percent of the dielectric, the remainder being gas.