COAX CABLE
Coax Cable
By Anne Ahira
Coax cable is sometimes referred to as its full name coaxial cable but most people use the shortened version, coax. It is an electric cable that has an inner conductor, which is then surrounded by a tubular insulating layer.
Ordinarily the flexile material that is used as a surrounding for the conductor is actually a conductive layer. That is characteristically either fine woven wire that will be useful because it’s so flexible, or sometimes it is a thin metallic foil. Regardless of which is used, it will be finished with a thin insulating layer right on the outside of the cable.
Actually the term coax cable comes from the outer shield and the particular inner conductor being able to share the exact identical geometric axis. Coaxial cable has been used primarily with computer network or Internet connections, in transmissions such as having to connect radio transmitters and/or receivers to their antennas, the distribution of cable television signals, or as a transmission line to send and receive radio frequency signals.
The largest benefit of using coax cable instead of other types of transmission lines is found in the properties of coaxial cable. You see in a “perfect” coaxial cable the electromagnetic field that carries the signal will exist only in the space found between the outer and inner conductors.
Thus, the coax cable “runs” may even be installed directly next to metal objects, such as a gutter, without suffering the power loss that will occur when using other transmission lines. In this manner, using the coaxial cable will provide a complete protection of the particular signals that can ordinarily come from external electromagnetic interference.
Readers need to be aware that there is a distinct difference between other shielded cables that carry lower frequency signals such as audio signals, and coax cable. There is a definite similarity between shielded cable and coaxial cable in that shielded cable will consist of a central wire, or perhaps a number of wires, that will be surrounded by a tubular shield conductor. However, shielded cable is not constructed using the very precise conductor spacing that is needed to function proficiently as a radio frequency transmission line.
The exact coax cable design choice will affect a number of items such as strength and cost, flexibility, power handling capabilities, attenuation, and frequency performance as well as affecting physical size. Its inner conductor may be solid or stranded, although stranded is much more flexible. In order to be able to receive improved high-frequency performance, sometimes the inner conductor will have been silver-plated. At times even copper-plated over plain iron wire will have been found to being frequently utilized for an inner conductor.
Sometimes the insulator that surrounds the inner conductor might be made of solid plastic, or a foamy type of plastic. It may even be made with air with spacers that support the inner wire. Ordinarily flexibility is a definite necessity but the majority of cable television (CATV) distribution systems will use what’s called “hard line” cables, meaning that the inside, the shield, may even be a solid wire as they will provide a lower signal loss.
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