75Ohm RG6 Coax Cable for CCTV Camera

     All of the common RG designations apply to various types of coaxial cable. Some people think "coax" or "coaxial" cable means "antenna cable," or "cable with F-connectors," or some such thing, but coax is a much more general classification. Any cable which has two conductors which share a single common axis is a coaxial cable--a center conductor, accompanied by a shield, the two being kept apart by a dielectric and wrapped in an outer jacket. All common video cable types are coaxial cables, though that's harder to see in some than in others--for example, s-video cable typically is two mini-coaxial cables combined either in a common outer jacket or a zip-cord type arrangement.

     Take RG-6, for example. The only thing one can say generally about RG-6 type coaxes is that they have an 18 AWG center conductor. An RG-6 might be a cheap generic CATV coax, designed strictly for economy, with a thin aluminum braid and a copper-coated steel center conductor; it might be a better-grade CATV coax, with an aluminum "quad shield" arrangement; or it might be a precision serial digital video coax like Belden 1694A, with a dense copper braid and double-foil shield, solid copper center conductor, nitrogen-injected PE foam dielectric, and extremely broad bandwidth and tight impedance tolerance. When people ask, "can I just use RG-6 for this application," the only correct answer is a question: what do you mean by "RG-6"? High-bandwidth serial digital video and cable TV distribution may both use RG-6 type cable, but that doesn't mean that the cable for one is necessarily suitable for the other.