Why is Coaxial Cable Used?

Designed for carrying high-frequency signals and protecting them from external-source electromagnetic interference, coaxial cable’s most well-known use is for cable television. Broadband Ethernet applications, home-video equipment, closed-circuit television, ham radio, commercial radio and undersea cable systems use coaxial cable as well.

Often called coax, coaxial cable is an ordinary style of shielded data-transmitting cable consisting of two coaxially oriented conductors separated with dielectric insulation. A metal wire surrounded with nonconductive dielectric insulation serves as the first conductor. Metallic mesh, braid or foil covers the insulation and provides the second conductor. A protective outer covering locks out impurities and moisture as it holds the cable together.

Cable television companies use mainly coaxial cables to transmit television service to customers, and most modern homes usually have one or more outlets for coax cables in every room. Customers can connect coax cables to their television sets or cable boxes directly from the wall outlets.

Consumers use coaxial cables primarily to connect various audio and visual equipment like VCRs to their television sets. Many people attach personal antennae to their televisions or digital converter boxes with coax cables as well. Although not without faults, the coax cable’s compatibility with most televisions, VCRs and other audio and visual products ensures that it remains the most popular cable of its kind in today’s electronic market.

 

Video

The cable industry has used coaxial cable for many years to transfer video signals. Most US homes that have cable television service have coax cable connections for TVs, and most modern televisions in the country have coaxial connectors. Before media cables made the use of standard audio and video jacks possible for connecting video peripherals, people usually used coax cables for that purpose. However, people often prefer cable jacks now because they are more flexible and affordable than are coaxial cables.

Coaxial Cable Advantages

Most of the electronics on the market are compatible with the cable because coaxial is the default cable for its type. Although composite video and audio cables are gaining in popularity for visual and audio purposes, they are incompatible with some electronics, making them impractical compared to coax cables. Coaxial has the capability to protect televisions from interference, which helps provide the best quality of pictures along with static prevention. In addition, coax cables are relatively inexpensive.

Coaxial Cable Disadvantages

Consumers should be aware of several inconveniences associated with coaxial cables before making decisions about using them. Many consider them bulky, and there is no way to make them smaller. In addition, they are often available in only one length, making it necessary to purchase more cable than needed. Installation of coax cables can be difficult because consumers must screw them onto their receiving electronic equipment and ensure that the screw tracking of the coax matches the receiving unit. Removing the cables can be difficult as well and may require some muscle and the use of a tool like a wrench.

Quality

Inferior cables will provide unsatisfactory results, so it is important to use high-quality coaxial cables. For superior picture quality, there must be a strong connection between the wall outlet and the television or between the DVD player and the monitor. Snowy picture quality may be the result of using inferior coax cables. The best coaxial cable has high-quality components and is highly durable. In addition, consumers can now choose from a variety of colors and lengths when purchasing coax.

Leakage

Aeronautical and radionavigation bands in the US use the same frequencies that cable signals use, and the FCC regulates cable television signal leakage to prevent radio frequency interference with mechanisms in the vicinity. Signal leakage occurs when electromagnetic fields pass through a cable’s shield. An outside signal passing into the cable can cause disruption of the signal along with noise. When a signal meant to remain in the cable passes outside of it, the result may be a weakened signal at the cable’s end. Cable-shield faults or improperly installed connectors can cause serious leakage. Aside from complying with FCC regulations, consumers want to keep leakage to a minimum to prevent picture ghosting and unwanted noise that can occur when outside signals enter the cable. Too much noise can even overpower the signal and make it ineffective.

There will always be a certain degree of leakage through a cable shield, but the amount is usually minimal and not enough to cause a problem. A perfect shield would be an ideal conductor with no gaps, bumps or holes connected to a perfect ground. However, such a shield would be costly, heavy, inflexible and impractical, so there must be compromises between the cost, flexibility and efficacy of the shields.

Since the days of sending messages by telegraph, early types of coaxial cables have carried signals across cities, countries and oceans. Coax cables first transmitted TV pictures and phone signals in the 1930s. Coaxial cables provide the only options for television connection in many circumstances, and many devices rely on the simple and adaptable standard. Coax cables will likely be transmitting signals for many more years.