Coaxial Cable

Coaxial cables, commonly called coax, are copper cables with metal shielding designed to provide immunity against noise and greater bandwidth. Coax can transmit signals over larger distances at a higher speed as compared to twisted pair cables.

Structure of Coaxial Cables

Coax has a central core of stiff copper conductor for transmitting signals. This is covered by an insulating material. The insulator is encased by a closely woven braided metal outer conductor that acts as a shield against noise. The outer conductor is again enclosed by a plastic insulating cover.

Categories of Coaxial Cables

Coaxial cables are categorized into three types as per Radio Government (RG) ratings:

Advantages and Disadvantages

Advantages

• High bandwidth − Can carry multiple signals simultaneously

• Noise immunity − Metal shielding provides excellent protection against electromagnetic interference

• Long distance transmission − Less signal degradation compared to twisted pair

• Better security − Difficult to tap without detection due to shielding

Disadvantages

• Higher cost − More expensive than twisted pair cables

• Installation complexity − Thicker and less flexible than other cable types

• Single cable failure − Can affect entire network segment

Applications of Coaxial Cables

• Analog telephone networks − A single coaxial cable can carry about 10,000 voice signals

• Digital telephone networks − Achieves data rates up to 600 Mbps

• Cable TV networks − Standard for television signal distribution

• Traditional Ethernet LANs − Used in early Ethernet implementations

• Metropolitan Area Networks (MANs) − For high-speed city-wide connections

Conclusion

Coaxial cables provide excellent noise immunity and high bandwidth through their unique shielded structure with a central conductor, insulation, metal shield, and outer sheath. While more expensive than twisted pair, coax remains essential for cable TV, telephone networks, and high-speed data transmission applications.