A coaxial cable is a common type of data communication cable. There are many different types of coaxial cables. In hooking up a Comcast cable box, the Comcast manual specifies that you need a 75 ohm coaxial cable with F-type connectors.
Ohm is the unit of measurement used to indicate the amount of resistance acting upon an electric current as it flows through a circuit. "F-type connectors" are screw-on connectors.
Another thing to consider is the RG value of the coaxial cable—such as "RG-6." "RG" stands for Radio Guide. The value that follows it is a reference to the diameter and internal characteristics of that particular type of coaxial cable. Comcast does not specify a standard RG value for the best type of coaxial cable to use with their products.
Common Coaxial Cables for Cable TV
"RG-6" and "RG-59" are two common types of coaxial cables used in homes for cable TV.