Coaxial Cables Explained: How They Work and Why

1What Is a Coaxial Cable?

A coaxial cable is a type of electrical cable built from concentric layers that all share a common central axis, which is where the name comes from. At its center sits a solid or stranded copper conductor that carries the actual signal.

Surrounding that core is a layer of insulating dielectric material, then a braided or foil metal shield, and finally a protective outer jacket. This layered structure lets coax carry radio frequency signals over long distances while resisting outside electrical noise.

2The Four Layers of a Coax Cable

Every coaxial cable is built from the same four parts, and understanding each one explains why the cable behaves the way it does.

• Center conductor: usually solid copper or copper-clad steel, this carries the actual electrical signal.
• Dielectric insulator: a layer of plastic or foam that keeps the center conductor centered and electrically separated from the shield.
• Shield: a braided copper mesh, foil layer, or both, that reflects electromagnetic interference away from the signal path.
• Jacket: an outer plastic layer that protects the cable from moisture, abrasion, and UV exposure.

3Why the Shielding Matters

Shielding matters because it is the difference between a clean signal and a snowy, static-filled one. Unshielded wires act like antennas, picking up stray electrical noise from anything nearby that produces an electromagnetic field.

Coax's braided or foil shield intercepts that noise before it reaches the center conductor, and it also keeps the cable's own signal from radiating outward and interfering with other equipment. That two-way protection is why coax was the backbone of cable television, early computer networking, and antenna feeds for so long.

4Impedance and Common Cable Types

Coaxial cable is rated by impedance, measured in ohms, and this rating must match the equipment on both ends or the signal reflects back instead of passing through cleanly.

• RG-6: 75 ohm impedance, the standard for cable TV, satellite dishes, and modern broadband internet drops.
• RG-59: 75 ohm impedance, thinner and older, once common for analog video and CCTV but largely superseded by RG-6.
• RG-58: 50 ohm impedance, used in amateur radio, older Ethernet networks, and general RF test equipment.
• Hardline coax: thick, low-loss coax used for long antenna runs and cell tower feeds.

5Connector Types and Compatibility

The connector on the end of a coax cable matters just as much as the cable itself, and the two must be matched to the equipment they plug into.

F-connectors are the threaded, screw-on type found on nearly every home cable and satellite installation. BNC connectors use a quick quarter-turn twist-lock and show up on professional video and test equipment. N-type connectors are larger, weatherproof, and common on outdoor antenna and cellular installations.

6Coax vs Fiber vs Twisted-Pair Cable

Coax sits between twisted-pair copper cable and fiber optic cable in terms of bandwidth and distance, which is why each still has its place today.

Twisted-pair cable, like the Ethernet cable running to a laptop, is cheaper and easier to terminate but more susceptible to interference over long runs. Fiber optic cable carries light instead of electricity, supports far higher bandwidth over much longer distances, and is immune to electromagnetic interference entirely, but it costs more to install and requires specialized tools to splice.

7Where Coax Is Still Used Today

Coax has been replaced by fiber for internet backbones and by twisted-pair for most local networking, but it has not disappeared.

• Cable television and cable internet, the last stretch from the street junction into the home.
• Satellite TV and satellite internet dish feeds.
• Antenna and radio frequency connections for amateur radio and broadcast equipment.
• Closed-circuit security camera systems using older analog standards.

8Troubleshooting Common Coax Problems

Most coax problems trace back to a handful of physical causes rather than anything electronic. A loose or corroded connector is the single most common source of a weak or dropped signal, since even a small gap breaks the shield's continuity.

Sharp bends in the cable can crush the dielectric layer and change its impedance at that point, which shows up as signal loss or reflections. Splitters also reduce signal strength each time the line divides, so a chain of several splitters can leave a distant television with a noticeably weaker picture than one closer to the source.

9Getting Started and Next Steps

If you are wiring a home for cable internet or satellite TV, RG-6 with quality compression F-connectors is the safe default choice for nearly every residential job. Keep runs as short and straight as practical, and avoid daisy-chaining more splitters than necessary.

Understanding coax is a useful stepping stone into broader networking and infrastructure topics, from how signals travel across physical media to how they get routed once they reach a modem or router. SkillVeris covers these fundamentals in more depth across its networking glossary and topic guides.