A strong, flexible, high-capacity cable widely used in audio, video and data applications. Commonly called "coax" (pronounced "
co-axe"), the cable comprises a solid or stranded wire in the center, surrounded by insulation. The insulation is wrapped with a metallic foil or braided wire that serves as the ground line and interference shield. All of this is enclosed in a plastic cover, which may have a fire-safe Teflon coating.
There Are Many Types
Typically with impedances of 50 or 75 Ohms, cables have different outside diameters and maximum capacities for operating voltage. Designated with an RG (radio grade) prefix such as RG-6, cables are also rated for signal loss (attenuation in dBs per 100 feet). Following are common types; however, there are many more in use. See
RCA connector and
F connector.
Impedance Core Layers
Range in Dia. in
Type Ohms (mm) Sheath
RG-6 75-76 1.0 2
RG-6 Quad 75-76 1.0 4
RG-58 50-53.5 0.9 1
RG-59 73-75 0.81 1
RG-59 Quad 73-75 0.81 4
Coaxial Cable
Coax uses two wires. The inner wire is the primary conductor. The ground wire is an aluminum or copper sheath that surrounds the insulation of the primary conductor and also serves as a shield against external interference.