Coax cable is a type of electrical cable consisting of an inner conductor surrounded by a concentric conducting shield, with the two separated by a dialectic (insulating)(material); many coax cables also have a protective outer sheath or jacket. You can refer it as either coax or coaxical cable. The term coax refers to the inner conductor and the outer shield sharing a geometric axis. The technology has been around since the early 20th century, with these cables mainly being used to connect satellite antenna facilities to homes and businesses thanks to their durability and ease of installation.
Coax cable is a type of transmission line, used to carry high-frequency electrical signals with low losses. It is used in such applications as telephone trunk lines, broadband internet networking cables, high-speed computer data bases, cable television signals, and connecting radio transmitters and receivers to their antennas. It differs from other shielded cables because the dimensions of the cable and connectors are controlled to give a precise, constant conductor spacing, which is needed for it to function efficiently as a transmission line.
Coax cable (Figure 7-10) has a single wire with a very high capacity (that is, a large bandwidth). The conductor is wrapped in insulation, which is, in turn, covered with a wire mesh that keeps out electrical “noise” (static). The great capacity of coaxial cable allows it to carry many channels simultaneously, eliminating the need for thousands of separate wires to be strung. Cable TV companies use coax cable to bring many channels of subscription television programming to residences. Coaxial cable is also popular in local networking.
How does Coax Cable works?
Coax cables are a popular choice because their shielded design allows the centre conductor to transmit data quickly while being protected from damage and interference. Coax cables are mainly built up of these four different layers:
- A centre conductor which is usually a copper wire, which data and video travels through
- Surrounding the copper wire is a dielectric plastic insulator
- A braided mesh made from copper then helps to shield the cable from electromagnetic interference (EMI)
- The external layer is a plastic coating which protects the internal layers from damage
Coax 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.
Benefit of using a Coax Cable
- Coax cable are not expensive
- it is easy to wire and install
- It is easy for you to expand
- It is a good resistance to EMI
- It is up to 10Mbps capacity
- It can be relied on because of it durability
Note: the main disadvantage of using coaxial cable is that single cable failure can take down an entire network.
Types of Coax Cable
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.
How to use a Coax Cable as an Antenna
Plug a coaxial cable into your TV’s antenna port. Grab an insulated electrical cord (do not plug it in) or an unpainted wire coat hanger and set it on the ground next to the TV. Position the pin on the end of the coaxial cable so that it rests on the bare metal of the cord’s prong or the wire hanger.
Using your coax cable TV antenna is simple, just like any commercially produced antenna. Screw it into the antenna input on your TV, then use your TV remote to access your TV’s menu. Set it to antenna or over-the-air, then perform a channel search. In my case, depending on where I am in the house, I can pick up anywhere from 38 to 51 channels. It performs about as well as most $6 antennas, yet better than some. I made one to replace a $6 antenna that worked poorly and liked it so much I made two more.