coax cable, called coaxial because it has a center conductor, and a concentric shield conductor,  coax sharing the same axis. It is used primarily as a feed line for rf to and from antennas, also between components in an audio video system. there are  many different kinds  of cable, from the thin stuff that comes with a cheap dvd player to  inch or larger feed lines for commercial installations.  There are antennas that use part of a coax cable, such as a coaxial dipole, where the shield is pulled bak ove itself to form half of a dipole antenna, leaving the center conductor and insulation, called the dielectric  as half of the antenna., but most commonly it is used as feed line.  You might be interested to know that although the shield is one conductor, it functions as two conductors at rf  frequencies, which is why it works well as a shielded feed line. the rf flows on the center conductor and the inside of the shield, not the outside.. that is why you can make a could out of coax, or use ferrite chokes to eliminate rf flowing down the coax back to the shack.
73 kb7nla
On Aug 2, 2013, at 4:32 PM, RJ Sandefur <[log in to unmask]> wrote:

> What is coax? Is that what you make your antana from? RJ