Coaxial Cable (Meaning and Explanation)

We explain what a coaxial cable is, the parts that make it up and its common applications. Also, its advantages and disadvantages.

What is a coaxial cable?

Coaxial or coax cable it's a type of wire commonly used in the transmission of electrical signals for communications networks or computer networks.

Its name comes from the fact that consists of two conductive materials arranged concentrically along the same axis: The central one is covered by an insulator which in turn is covered by the other conductor, thus building an electrically shielded transmission circuit.

Coaxial cable was created in the 1930s, and quickly replaced twisted pair cable, since it allowed faster and more secure transmission of information. Today it is being replaced by fiber optics, more compatible with contemporary needs for high frequencies and digitalization of transmissions.

Uses and applications

Coaxial cable is an excellent option when you need send information or current over long distances in a safe way.

Before being displaced by fiberglass, it was widely used for these purposes, underground and even underwater, especially for analog telephony and certain digital transmission systems.

Nowadays it is common to find a coaxial cable connecting:

The satellite antenna and the subscription television decoder;
The issuers of shortwave radios and its broadcast antenna;
In the video signal distribution lines ;
In submarine cables and telephone networks interurban.

Coaxial cable parts

coaxial cable components parts — In a coaxial cable, two conducting elements are separated by an insulator.

A coaxial cable is made up of the following parts:

Core Located in the center of the cable, it consists of a single cable called “solid”, although it may eventually be several wires in one. It is the main route of electrical and electronic information that the cable allows.
Dielectric Around the core there is an insulating layer known as a dielectric, whose function is to keep two components whose contact would produce a short circuit, such as the core and the mesh, separated.
Braided thread mesh Covering the dielectric is a braided metal mesh, which serves as a screen to protect the core from radiation and interference, and therefore guarantees the fidelity of the transmission. It is possible that in some cases, apart from this braided mesh, there is a metal sheet covering the dielectric (double shielding).
Outer cover This is the “skin” of the cable, which surrounds and covers it, and is usually made of Teflon, rubber or plastic (PVC), thus serving as a protector and insulator. It is usually painted black, too.

Advantages and disadvantages

Compared to previous cable models, coaxial represented a huge leap forward. On the one hand, It is flexible but at the same time resistant to attenuation and interference since the braided wire screen absorbs lost signals and isolates the information transmitted within the cable.

Besides, supports large amounts of data in a physical system that is rather simple to manufacture.

However, given the contemporary transmission needs, typical of the digital era, coaxial cable reveals its limitations: transmits simple signals, without frequency modulation and incidentally requires special terminals for the physical connection.

For this reason, today it is preferred to use fiberglass, with which, in addition, there is no risk of short circuit when damaged cables.

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