Most commonly used for data communications, coaxial cable is a type of TV cable with multiple layers. The innermost section is simply copper wire with insulation (dielectric) surrounding it. Next it is covered in copper mesh (foil or braided conductor) and covered with an outer insulation jacket, which grounds it. The insulating dielectric has a big impact on the cable, including the cable’s capacitance and inductance. At its most basic, the coaxial cable, or coax cable, is a transmission path for high frequency electrical signals without interference.
Though many varieties will have a solid dielectric, it’s possible to have a foam one with a lot of air or some other type of gas. This reduces losses with the use of a larger diameter conductor at the center. Foam variations can provide up to 15 percent less attenuation. The downside is its absorption of moisture, which increases the loss.
This cable is one that cable television companies use between the users (homes and businesses) and the community antenna. The derivative of the name coaxial is based on the fact that the cable has one physical channel carrying the signal surrounded by another concentric physical channel, and these both run along the same axis. These cables can carry information for a great number of miles. Sometimes they are also used by phone companies from a central location to poles near users, or by businesses for Ethernet or LAN connections.
Invented in 1880 by Oliver Heaviside, an English mathematician and engineer, the coaxial cable wasn’t established as a cross-continental system until 1940 by AT&T. The structure of the cable that includes a proper insulating material ensures a closed signal that won’t be affected by noise interference along its traveled path.
As mentioned, materials and dimensions, the insulating dielectric especially, play a big role in the success of the cable’s use. Since characteristic impedance is sensitive to signal frequency, the cable must have a dielectric that won’t attenuate the signal if above 1 GHz. The application dictates the electrical characteristics of coaxial cable, with a standard example of a moderate power environment being the use of 50 Ohm. Residential installation antennas are at something more like 75 Ohm.
There is more than just one type of coaxial cable. For example, some have simple connectors and some have complicated combo links and connections for a different application. Not all of them will be super stiff either, though this is common because the construction, amount of insulation and thickness of wire.
There are fundamental electrical parameters that go along with a coaxial cable. And, of course, there’s a way of calculating these. Brief examples are below.
For shunt capacitance per unit length,Again, all of this depends on the application and environment the cables will be in. Some issues associated with using coaxial cables can include signal leakage, noise, ground loops and common mode current. Electromagnetic fields can pass through the shield of a cable (or vice versa) and can cause noise or signal disruption.
For more on cables and installation: “How to Install Multi Conductor Cable Wire”，Click here for info on multi-pair cables，On RG59 and RG6 coax cables.
