If you need to splice a coax cable you will have to acquire a few specialized tools and small components. These can easily be found at your local electronics or hardware store.
Step 1 - Determine What Cable Type You Have
The most common cables for home use are RG6 and RG59. The cable-type is marked on the cable. If you cannot find any markings to indicate the cable type, you can measure it. RG6 has a diameter of about .274 inches and RG59 is about .233 inches. A simpler solution might be to just cut off a piece and take it with you when buying your components.
Step 2 - Strip the Cable
It is important to use a coaxial cable stripper to strip the coax cable, exposing about a half-inch. The stripping tool will accommodate different sizes of coax cable and will have an adapter to accommodate your cable type. Coax cables are not the same as other electrical cables and the coax cable stripper is built to accommodate and strip the layers of the cable without cutting or damaging the innermost copper wire, which will ultimately protrude in order to mate with the female barrel coupler. When you have completed the stripping you will have a cable with an exposed white insulator covered by a wire mesh jacket with a copper wire protruding. Fold the mesh jacket back over the outer cable casing so that the insulator is bare. Your cable is now ready for the connector.
Step 3 - Install the Compression Connector
Slide the compression connector onto the cable, being careful to not damage the protruding copper wire. The center copper wire should protrude just slightly beyond the end of the connector.
Step 4 - Adjust and Employ Your Compression Tool
For this step, a specialized tool will firmly seat the crimp-ring onto the ends of the coax cable over the inserted part of the connector. Your compression tool will have adapters for your cable type. It will generally have the capability to be used for RG6 and RG59 coax type connectors, as well as other non-coax compression connectors. Insert the cable with the crimp-ring loosely mounted into the compression tool where indicated and squeeze the handle to crimp the ring over the cable and connector.
Step 5 - Repeat Steps
Repeat steps 1 through 3 for the other cable that you need to splice.
Step 6 - Connect the Two Cables
You will now attach each cable to the feed-through or barrel connector. You will notice that your barrel connector will have a female connection port on both sides into which the copper wire from the two cables will be seated. Tighten the collar of the cable connector onto the barrel connector on each side. Your splice is now complete.
If you are splicing cable for the purpose of extending your cable you will have to buy enough connectors to prepare four cable ends. Keep in mind that any additional cable being spliced in should be the same type of cable, either RG6 or RG59. Also note that this type of cable connector, once properly mounted, will make the connection weatherproof and appropriate for outdoor use as necessary.