Most CB and HAM radio operators use coaxial (coax) cable to feed their antenna. Another name for the cable you use to hook your radio to your antenna is “feed line”. Feed line is a generic term for all types of cable including coax. Coax has been around for a long time and became very popular with Radio Amateurs after World War II, when army surplus stores were filled with miles of coax cable. This is one of them main reasons why we use coax today, it became such a trend of sorts. Coax cable consists of two concentric wires, as shown in figure 1. It is important to note that coax cable is unbalanced, no current flows on the outside shield of the cable. This is in comparison other types of feed line that are balanced such as twin-lead, which you may be familiar with from your old TV antenna. Figure 1 shows a close up of the end of coax, and its makeup.