Coaxial cable has a distinct thick, round shape because of its interior insulation layer. Its size makes it look very different to other types of cable, such as twisted pair or Ethernet cable. The most commons sizes of coaxial cable are RG-6, RG-11 and RG-59 – some of the size differences are demonstrated in the image below.

Coaxial cables are available in a variety of colours including black, brown and white.

Coaxial cables are a popular choice because their shielded design allows the centre conductor to transmit data quickly while being protected from damage and interference.

Coaxial cables are mainly built up of these four different layers:

1. A centre conductor which is usually a copper wire, which data and video travels through
2. Surrounding the copper wire is a dielectric plastic insulator
3. A braided mesh made from copper then helps to shield the cable from electromagnetic interference (EMI)
4. The external layer is a plastic coating which protects the internal layers from damage

Coaxial cable works by carrying data in the centre conductor, while the surrounding layers of shielding stop any signal loss (also called attenuation loss) and help reduce EMI.

The first layer, called the dielectric, provides distance between the core conductor and the outer layers, as well as some insulation.

The next layers, collectively referred to as the shield, keep electrical impulses and radio transmissions out. The different layers of a coaxial cable are shown in the image below:

The transmission speed of coaxial cable is 10Mbps (megabits per second), and they offer 80 times more transmission capacity than twisted pair cables.

Advantages of coaxial cable

• Inexpensive
• Easy to wire and install
• Easy to expand
• Good resistance to EMI
• Up to 10Mbps capacity
• Durable

Another benefit of coaxial cable is the electromagnetic field carrying the signal exists only in the space between the inner and outer conductors. This means coaxial cable can be installed next to metal objects without losing power, unlike other types of transmission lines.

Disadvantages of coaxial cable

The main disadvantage of using coaxial cable is that single cable failure can take down an entire network.

There are two main types of coaxial cables – ones with an impedance of 75 Ohm (Ω) and ones with an impedance of 50 Ohm.

Cables with 75 Ohm are mostly used for video signals, while 50 Ohm cables tend to be used for data and wireless communications.

In coaxial cables, Ohm refers to the impedance, which is the measure of resistance in the cable to the flow of electrical energy.

What’s RF coaxial cable?

RF coaxial cables are used to carry radio frequency signals. They’re the standard input cable on TVs and feature a single pin that plugs into the RF input on a device.

What’s RG-6 cable?

RG-6 cables have larger conductors, so they provide better signal quality. They have thicker dielectric insulation and are made with a different kind of shielding, allowing them to handle GHz level signals more effectively. As this type of cable is thin, it can also be easily installed in walls or ceilings.

What’s RG-59 cable?

A common cable in domestic settings, RG-59 cable is similar to the RG-6, but it has an even thinner centre conductor. This makes it a good choice for short runs and low-frequency transmissions.

What’s RG-11 cable?

RG-11 cable is easily identifiable as it’s thicker than other types of coaxial cable, which can make it more difficult to work with. However, it offers a lower attenuation level than RG-6 or RG-59, meaning it can carry data for longer distances.

Here are some of the different uses for coaxial cable and which type is most suited for the task:

When coaxial cable lines are produced, they only provide one signal to power a singular device. This can be problematic if there’s more than one device that requires a signal.

Coaxial splitters are used when there’s more than one device that requires a signal. They’re small devices designed to attach to coaxial cable to split the signal into several lines to connect to multiple devices.

A coaxial port is a single female RCA connector. The port on a device is most likely to be labelled as 'coaxial', but could also be something such as 'digital out' or 'digital in'. To help distinguish it, the coaxial port is usually colour-coded orange or black.

To help identify the different types of coaxial cable, here’s a size guide:

Coaxial cable connectors are used to connect cables to other devices and maintain the cable’s shielding.

There are two distinct connector styles – known as male and female. Male connectors have metals pin which protrude from the centre and female connectors have a recessed hole to receive the pin.

Here are some of the most common coaxial connector types and their applications: