99 percent of the time, an antenna feed system consists of coaxial cable plus connectors, jumpers, and lightning arresters. 1 percent of the time, a feed system consists of waveguide. Waveguide is heavy, expensive, and low loss compared to coax. A full description of waveguide is beyond the scope of this book; however, in brief, waveguide is like running a rectangular, circular, or elliptical metal pipe up a tower to connect the radio and the antenna. Wireless energy is carried inside the waveguide until the energy reaches the antenna.
Consider the following coax characteristics when selecting the proper coax for your antenna feed system:
Upper frequency limit
The sections that follow ...