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A coaxial cable or coax cable, for short, is an electrical cable that transmits radio frequency (RF) signals from one point to another.
Internet providers, telephone companies, and cable operators all over the world use them to convey data, voice, and video communication to customers.
They are primarily used by cable TV companies to connect homes and businesses to their telecommunication facilities.
They have a physical channel responsible for carrying the signal, surrounded by an insulation layer, followed by another physical channel that all run along the same axis. The outer channel functions as a ground.
With so many options available on the market today, choosing the right one can be quite difficult, especially if you don’t know what to look for in the first place.
In this guide, we’ll take an in-depth look at everything you need to know about them to choose the best coaxial cable that guarantees the best results.
Coaxial Cable Reviews
KabelDirekt Digital Coaxial Audio Video Cable – Best Overall
This RG6 A/V coax cable has an oxygen-free copper center with thick double-shielded aluminum braiding insulation.
It comes with 24K gold-plated F-type connector pins to provide a corrosion-resistant interface for male-to-male antenna connectors, digital routers, satellite TV receivers, and televisions alike.
AmazonBasics CL2-Rated Coaxial TV Antenna Cable
This 75-Ohm RG6 A/V solid center coaxial cable comes with two nickel-plated F-type male connectors. It connects off-air antennas, satellite receivers, cable modems, and TVs, providing a clear signal without any RF or electromagnetic noise.
Mediabridge Tri-Shielded CL2-rated Coaxial Cable
Mediabridge coaxial cables are highly-rated for use in F-type female equipped off-air antennas, satellite receivers, cable modems, TV, and a host of other devices.
The nickel-plated connectors in this tri-shielded cable come with removable grip connector caps. These simplify the installation and removal process tremendously.
Hosa BNC to BNC Coaxial Cable
This BNC-to-BNC cable comes with an oxygen-free copper center for accurate signal transfer and enhanced clarity. It comes with Al-Mylar and copper-braided shields to eliminate any potential for electromagnetic interference.
Velocity S/PDIF Digital Audio Coax Cable
If you have a high-fidelity digital device with a Sony/Philips Digital Interface, this S/PDIF coaxial cable is perfect for your TV, cable box, media player, satellite, or any other unit with a coaxial audio output.
It has corrosion-resistant molded gold-plated connectors that protect the conductor against strain and damage.
How Does a Coaxial Cable Work?
The best coaxial cable should have three layers made up of electrical conductors and insulating material.
The whole idea behind this setup is to ensure that the signals being transmitted are enclosed inside the cable to minimize interference that would otherwise result from surrounding electrical noise.
Electrical noise is essentially any unwanted signals generated from electronics, gadgets, or even other cables that distort the original signal.
Let’s go a little deeper. The centermost layer is a thin conducting wire that is typically solid or braided copper. This is surrounded by a dielectric layer, which consists of insulating material.
Then there’s a layer of braided metal foil or copper mesh that forms the shield surrounding the dielectric layer. Both ends are grounded in the connectors to not only shield the signals but also to provide a means of dissipating external interference.
This elaborate construction is secured tightly in an insulating sheath.
The Making of a Good Coaxial Cable
The secret of a good coaxial cable design lies in the type of materials used in all the different layers. It involves maintaining tight control over the cable dimensions as well.
This ensures that its characteristic impedance (the opposing force on an electric current flowing through an infinitely long conductor) takes on a specific designated value.
If this value doesn’t match a particular high-frequency signal, then the signal will be partially reflected. This will, in turn, lead to errors that cause distortion.
For signals above 1GHz, for instance, a coaxial cable manufacturer has to ensure that the dielectric used in the cable is made from a material that doesn’t alter the characteristic impedance in a way that causes the signal to be reflected.
In the same breath, they also have to use a material that doesn’t attenuate (signal loss over a specific distance) the signal too much.
How to Choose the Best Coaxial Cable
Several different types of coaxial cables exist in the market today. The choice of one over the other, all boils down to its intended purpose. Here’s what you need to consider.
1. Type of Cable
There are essentially two main types of coaxial cables based on their specific applications:
For Video
First, there are those used for video applications. These usually have an impedance of 75 Ohms (Ω). The most popular ones are RG6/U and RG59/U cables.
For wireless communications
Then there are those used for wireless communications and data. These typically have an impedance of 50 Ω, with the popular ones being RG316/U, RG188/U, and RG174/U.
They have stranded #26 AWG (American Wire Gauge) centers, which make for very flexible cables.
50 Ω low-loss cables are also a great alternative since they are known to provide far better shielding than RG-style coaxial cables. These are better suited for RF applications.
2. Signal Frequency
The other factor you need to consider is the operating frequency of the signal being transmitted through the cable. As the frequency increases, the signal energy tends to move away from the conductor at the center of the cable towards the shield surrounding it.
This phenomenon is known as the “skin effect” and has a direct bearing on the distance the signal travels at a specific frequency and power level. The higher the frequency is, the shorter the distance it travels.
The diameter or, more importantly, the surface area of the inner conductor also plays a critical role in reducing the loss of signal energy. Here are some key points to keep in mind:
- A coax cable with a larger core diameter means greater power handling and reduced attenuation. However, it also means reduced flexibility.
- A braided core may make for a more flexible wire, but it also means increased attenuation.
- A solid copper core offers greater electrical performance but is much heavier and costs significantly more than its stranded core cable counterparts.
Although multi-strand conductors have a larger surface area than their solid core counterparts, the air channels that exist between each stand amplify the skin effect.
However, if performance matters a great deal to you, then solid copper core coaxial cables are the best for high-frequency signal transmission.
3. Cable Attenuation
This refers to the rate of signal loss over a given distance. The rate of attenuation tends to be higher when the operating frequency of the signal being transmitted is high.
But, if you use a coaxial cable whose conducting center has a large diameter, the attenuation will be drastically lower.
An RG11/U cable with a #20 AWG conductor in its center can carry a signal at a specific power level and frequency to about half the distance that an RG59/U cable with an 18-AWG center conductor would.
So, depending on what you intend to use your cable for, ensure that you know the level of attenuation that’s acceptable for your specific application.
4. Characteristic Impedance
The characteristic impedance, or transmission impedance as it is sometimes called, is also an important consideration when it comes to performance.
Ideally, you want the characteristic impedance of the cable you get to match the load resistance.
Here’s what that means.
As a signal moves down a cable, you want it to have the same characteristic impedance every step of the way. When it stays constant, the signal quality remains the same.
However, if the transmission impedance changes somewhere along the line, then some of the signal energy gets reflected, which means that whatever continues will inevitably be a little distorted.
The most common coax cable impedance you’ll come across in the majority of applications are the 50 Ω and 75 Ω.
Coaxial Cable Types and Uses
There are several different types of coaxial cables available in the market today. Some of the most popular categories include:
- Hardline coaxial cables – These types are commonly used in transmitter-antenna connections. They rely on round copper tubing with a combination of various types of metals like copper or aluminum as a shield.
- Radiating cables – These are in many ways similar to the hard-line cables except that the shielding has tuned slots matched to the wavelength of the RF signal the cable will operate at. They have many applications in underground tunnels, military equipment, and are also commonly used in elevators.
- Rigid-line coaxial cables – These types are specially designed for indoor use between high-power RF transmitters. They have twin copper tubes that function as unbendable pipes.
- Triaxial cables – These types come with a third shielding layer that is grounded. It offers protection to the signals transmitted further down the cable.
As mentioned previously, most coaxial cable specifications typically have an impedance of 50 or 75 Ω.
However, due to the widespread use of 75 Ω RG-6 cables with double/quad shields in the cable TV industry, many other sectors have adopted them as the de-facto standard.
Others include the RG-214/U standard used for transmitting high-frequency signals and the RG-59/U standard used for transmitting broadband signals in CCTV systems. RG-11 is another popular one used for long-runs.
RG59 vs. RG6 Coax Cables
Cable modems and satellite televisions usually use these two types of cables. The RG59 cables were commonly used in older installations before the RG6 cables became the standard.
- RG59 cables are much thinner with a #20 AWG copper center conductor. You’re likely to find them in older buildings and are commonly used in analog video and CCTV systems.
- RG6 cables, on the other hand, are much larger with an #18 AWG copper center conductor. They are commonly used with high-frequency high-bandwidth hardware, where satellite and internet signals run at much higher frequencies compared to analog video and traditional CCTV systems.
Whether you’ll need an RG59 or RG6 cable ultimately boils down to the operating frequency of the application in question. If your system runs at a frequency above 50 MHz, then you should use an RG6 cable.
Coaxial Cable Connector Types
Coaxial cable connectors are used to connect the coax cable itself to the device. They are specially designed to maintain the shielding in the cable. There are two flavors of coax connectors – male and female.
Male connectors have a protruding metallic pin at their center. The female connectors, on the other hand, have a receptacle to receive the pin.
Depending on the frequency and size of the connector, some may also be sexless. These have a mounted-flush for the connection.
There are several different varieties of coaxial cable connectors within the RF, audio, video, and digital industries. Each of these offers unique benefits based on their application or end-use.
Here’s a list of some of the most common connector types you’re likely to come across.
- BNC – This is short for Bayonet Neil Concelman and is commonly used with video and television signals as well as RF with operating frequencies below 4 GHz.
- TNC – This is short for Threaded Neil Concelman, which is essentially a threaded version of the BNC. It’s commonly used in cellphones and has an operating frequency of up to 12 GHz.
- SMA – This stands for Sub-Miniature version A. It’s commonly used with RF and microwave systems, WiFi antenna systems, and cellphones. It has an operating frequency of up to 18 GHz.
- SMB – This stands for Sub-Miniature version B. It is commonly used with telecommunications hardware.
- QMA – This is a quick-locking variant of the SMA connector. It’s mainly used with industrial and communications hardware.
- RCA – RCA is short for Radio Corporation of America. They are also known as A/V jacks. They are the grouped-red, yellow, and white audio and video cables used with older TV sets.
- F-type connectors – These are used in cable and digital televisions. They typically use RG59 and RG6 cables.
Benefits of Coaxial Cables
Coax cables offer several advantages over other types of cables in the market. Here’s a quick run-through of their top benefits.
- Versatility – Coax cables can carry different types of signals ranging from RF and microwaves to data and video.
- Capacity – Since these cables are made up of several copper wires banded together, they can transmit large amounts of signals at very high rates, making them ideal for broadband internet connections.
- Frequency range – They are capable of transmitting multiple signal frequency ranges at the same time, making them a great choice for running more than one connection on the same line.
- Protection – Since these cables are covered with thick layers of rubber, the wires inside are protected against breakage, fire-breakout, and noise interference.
Do Your Homework
Choosing the best coaxial cable all boils down to what its intended purpose is. Identify the problem you’re trying to solve, which, in this case, means knowing the properties of the signals the cable will be carrying.
These include the power level, frequency range, and how complex the routing structure will be.
Once you identify the type of coaxial cable you require, pick a reputable brand based on the reviews you find online, and you’re good to go. The five cables detailed in this guide are a great place to start.
