Coaxial cables are high performance cables capable of bringing digital audio and video to your television or surround sound receiver. Structurally, there are four main components to a coaxial cable: a plastic outer layer, a layer of protective copper, an inner plastic tubing and finally the copper core. You might be surprised to hear that this technology, which remains a popular way to connect home theater components today, was originally invented over a century ago, by British engineer Oliver Heaviside in 1880.
Coaxial cables are used for a wide variety of purposes, from transferring radio and cable signals to measurement and data signals. Many people will be familiar with coaxial cables because of their heavy use in older entertainment peripherals, including TV antennas (popularly known as "bunny ears" in some cases) or game consoles from the 1980s or 1990s, including the original Nintendo Entertainment System and Sega Genesis. These systems used coaxial cable because the technology was cheap and because they were used years (or in the case of the NES, decades) prior to the rise of digital, or high-definition, capabilities.
Advantages of Coaxial Cables
The obvious advantage of buying a coaxial video cable (or accessories like a coaxial cable connector or coaxial cable splitter) is the low price. Even premium coaxial cables like digital coaxial cables are available for under $20, unlike component cables or HDMI cables which can run from $50 to $70 a set. Surprisingly, the best use for coaxial cables is for audio purposes, because they are in fact capable of transferring a high-quality digital audio signal.
Disadvantages of Coaxial Cables
Unfortunately, you do get what you pay for. Users who pick up coaxial cables for video purposes will not be getting the best picture quality out of their HDTVs. The problem with coaxial cables is that there is always some signal radiating away from the core, meaning they simply aren't as efficient as component or HDMI cables. Because coaxial cables carry radio frequency signals, they can't be converted easily to other types of inputs. There is no way to directly adapt coaxial cable to S video input, for example. You would have to plug the coax into a cable box or TV tuner (such as on a VCR) that can interpret the radio signal, and then use the S video output from that device to connect to your desired receiver, resulting in a loss of signal from multiple connections.
Also keep in mind that coaxial cables can degrade in quality over time if any of the internal layers break down. This can be heavily affected by the elements around the cable, particularly if you're running it from one part of the house to another (this is most often the case when splitting satellite or cable television signals). Keep that in mind if you've been using coaxial cables for several years.