If you have cable TV or a home video system or you’re connected to the internet by an Ethernet cable, you likely have coaxial cable in your house.
A coaxial cable is easy to spot. Unlike the flat wiring and cables that carry electricity to lamps and appliances, coaxial cable (often called coax) is round and fat. It is not difficult to work with, but it does require a little more care and some special tools to run the cable throughout your house and make the necessary connections.
What is coax?
Coaxial cable is designed to transmit high-frequency signals. The name "cable TV" comes from the cable's use in transmitting signals to individual homes. It is also designed to stop interference from magnetic fields that can interfere with the signal.
There are a number of different types of coax, but only two—RG-59 and RG-6—get the most use in residential applications. The name “RG” dates back to World War II and means “radio guide,” but it doesn’t really signify anything today. It’s just a term that stuck with the products.
RG-59 is the basic coax cable and best suited for cable TV transmissions and short cable runs. RG-6 is better for digital video signals and satellite TV.
The cable ends in a fitting that allows you to plug the cable into a device like a cable box. You can buy cable with the fittings already attached, but if you purchase large spools of cable, you will need to attach the fittings yourself.
Working with coax
Working with coaxial cable is different from working with standard electrical cable. Here are some tips for working with it.
- Do no harm. If the plastic coating is nicked, the insulation is crushed or the jacket is pierced, the signal will suffer. Avoid kinking or crushing the cable.
- Make rounded curves instead of sharp turns. When you change direction while running the cable, form the cable into a loop rather than a 90-degree turn. The sharp turn will crush the insulation and damage the signal.
- Create a drip loop. When running the cable from outside to inside the house, form a loop with the cable before it enters the hole you have drilled. This helps keep water out of the house. Place a plastic bushing inside the hole to protect the cable.
- Keep away from electric cables. Keep coax at least six inches away from electric cable. When the two are placed near one another, there is the possibility of signal interference. You can cross electric cable with the coax, but don't run them close together and parallel to each other.
- Be careful when securing the cable with staples. There are staples made to hold coax in place. Avoid crushing the cable when using a hammer to place the staples. There are cable staplers available that drive the staples the correct depth.
- Use low-voltage boxes for making wall connections. When you run cable inside a wall, it will need a place to exit the wall for a TV or other connection. If you use a standard electrical box, which is fully enclosed, you will need to bend the cable to get it to fit inside the box, which could damage the cable. A low-voltage box is just a frame that supports the wall plate that holds the cable connection. You can simply push the extra cable into the wall cavity without damaging it.
- Use a cable stripper. You can use a utility knife to strip the cable when making a connection, but it is easy to mess up and cause interference with the signal. An inexpensive cable stripper has two blades that leave only the center conductor exposed.
- Use compression fittings. There are screw-on fittings, but compression fittings will generally last longer. There is an inexpensive tool that allows you to connect the properly stripped cable to various fittings.
- Use a wrench to finish the connection. Many people hand-tighten coax connections. This often works fine for a while, but the fitting could loosen. You can use a 7/16-inch wrench to turn the hand-tightened connection a quarter turn to tighten it up.