Networking - Media - Guided - Coaxial

Coaxial cable is a type of guided media that consists of a central conductor, an insulating layer, a metallic shield, and an outer insulating layer. It is widely used for transmitting data and signals in various applications. 

Types of Coaxial Cable:

  • Thinnet (10BASE2): Thinnet coaxial cable has a thinner diameter and is commonly used for Ethernet networks in older installations. It supports data rates up to 10 Mbps and uses BNC connectors for connection.
  • Thicknet (10BASE5): Thicknet coaxial cable has a thicker diameter and is used for longer cable runs. It supports data rates up to 10 Mbps and uses Vampire Tap connectors for connection.
  • RG-6 and RG-59: These are commonly used coaxial cables for cable television (CATV) and satellite TV installations. RG-6 is thicker and offers better signal quality over longer distances, while RG-59 is thinner and suitable for shorter runs.

Applications where Coaxial Cable is Widely Used:

  • Cable Television (CATV): Coaxial cables are extensively used for transmitting television signals from cable service providers to subscribers' homes.
  • Internet Service Providers (ISPs): Coaxial cables are used by ISPs to deliver broadband internet connections to homes and businesses.
  • Surveillance Systems: Coaxial cables are used in CCTV surveillance systems to transmit video signals from cameras to monitoring devices or recording systems.
  • Data Networks: Coaxial cables, although less common in modern Ethernet networks, are still used in specific applications, such as long-distance data transmission or specialized industrial environments.

Maximum Range:

The maximum range of coaxial cable depends on various factors, including the type of cable, signal quality, and frequency. For Ethernet networks, the maximum recommended distance for thinnet coaxial cable (10BASE2) is approximately 185 meters (607 feet), while thicknet coaxial cable (10BASE5) can support distances up to 500 meters (1640 feet) without signal degradation.

Advantages of Coaxial Cable:

  • Bandwidth: Coaxial cable offers higher bandwidth compared to twisted pair cables, making it suitable for transmitting large amounts of data.
  • Long-distance transmission: Coaxial cable can support longer cable runs without significant signal degradation, making it suitable for applications that require distance coverage.
  • Resistance to interference: The metallic shielding in coaxial cable provides good protection against electromagnetic interference (EMI) and reduces signal loss.
  • Durability: Coaxial cable is relatively durable and resistant to environmental factors such as moisture and temperature.

Disadvantages of Coaxial Cable:

  • Bulkiness: Coaxial cable is thicker and less flexible compared to twisted pair cables, making it more challenging to install and manage, especially in tight spaces.
  • Cost: Coaxial cable is generally more expensive than twisted pair cables, especially in installations requiring specialized connectors or higher-quality cable.
  • Limited flexibility: Coaxial cable is less flexible than twisted pair cables, which can limit its use in certain applications.

Electromagnetic Interference (EMI):

Coaxial cable provides good protection against electromagnetic interference due to its metallic shield. The shield helps to prevent external interference from affecting the transmitted signals. However, if the cable is improperly grounded or the shield is damaged, it can increase the risk of EMI.

Attenuation:

Attenuation refers to the loss of signal strength as it travels through the cable. Coaxial cable experiences attenuation, particularly over longer distances. The signal strength gradually diminishes, which can result in degraded signal quality and data transmission. Signal amplifiers or repeaters may be used to compensate for attenuation in longer cable runs.