Many of our home-based entertainment devices today have a plethora of ports installed into them, either at the front or the back (and sometimes even both in some cases). Those ports serve various purposes and functions such as a display (HDMI, Display Ports & RCA), audio (3.5mm & 6.35mm audio ports), internet connection (ethernet ports), and even data transfer (USB A to C and USB 3.0).
But one certain port that will always be present in any kind of device would be the coaxial ports. The main reason why this old yet trusted port is still being installed in newer and modern devices is that many manufacturers and brand makers are still supporting coaxial cables for various types of signal transfer. Therefore, it makes coaxial cables still relevant in the modern age of devices and gadgets.
But why are coaxial cables still being used nowadays even though there are many faster and better options? Are there any kinds of coaxial cables that you should be informed of beforehand? And how does a coaxial cable exactly work?
What is a Coaxial Cable?
You might have heard its name before numerous times, but what exactly is a coaxial cable? A coaxial cable (sometimes called coax cable) is a type of electrical cable that can transmit RF (Radio Frequency) signals from the source to an input device that has its own coaxial port.
Do take note that the range of that particular RF signal will span both the upper level of the audio spectrum and the lower levels of the infrared spectrum. When converted into a range of numbers, that amounts to 20kHz (kilohertz) to 300GHz (gigahertz).
When it comes to technical terms, the word “coaxial” pertains to the overall construction of the cable itself, as it is constructed wherein the central inner cable core (the copper cable) along with a dielectric insulator (the white foam-like material) are wrapped together by a woven copper shield around it, as seen on the image below:
To protect people from being electrocuted by the coaxial cable (remember, it is still an electrical cable that transfers RF signals which are basically electric currents), there is a plastic jacket (an insulator) that covers up the insides of it.
As for its history, you might be surprised that the cable itself is more than a century-year-old, as it was first used in 1858. However, the patent for this technology was only applied 22 years later (1880) only when an English physicist, engineer, and mathematician by the name of Oliver Heaviside fully understood it well and its usage under the British patent no. 1,407.
The coaxial cable in appearance is simple, as it is primarily covered in a black plastic insulator sheet that has a leather sensation when touched. The appearance of the insides is explained in the image above as a reference.
Materials of a Coaxial Cable
When it comes to the materials used in making a coaxial cable, it depends on each component of it. First, the center copper rod is usually built up of copper-plated steel. However, if that material isn’t available for production, then stranded copper will be used instead.
As for the materials for the dielectric insulator, the commonly used materials for it can be the following: solid plastic, foam plastic, or air with spacers.
For the shield part of the cable, the commonly used material is a braided copper wire. However, in higher-quality and other versions of a coaxial cable, a silver-plated braid is used instead. There are even some that use two shields at once, which is achieved by combining aluminum foil with braided copper wire.
For more protection, there are even coaxial cable designs that use two layers of both aluminum foil and braided copper wire as shielding. The purpose of shielding is to improve RF signal transfer performance while preventing loss during transfers. The only downside to that is the cable becomes thicker and less flexible, which can be a downside to others.
The outer layer of the coaxial cable, commonly nicknamed as “jacket,” commonly uses PVC (Polyvinyl Chloride), in which cases are fire-resistant. There are some that are even resistant to oxidation, ultraviolet light, and water resistance.
Pros and Cons of Using a Coaxial Cable
Coaxial cables are commonly used today for radio transmissions, as well as telecommunications, WiFi systems, cable TV, and cable modems. Even for an old piece of technology, many industries globally are still using it for everyday work and processes. The main reason for that is the usage of a coaxial cable offers a lot of pros which outweighs its cons considerably enough.
The first major advantage of a coaxial cable is that it is less susceptible to both electromagnetic and radio-frequency interference. Furthermore, the cable allows higher frequency applications amounting up to 50 MHz and higher.
Another advantage that coaxial cable provides is that it has both high transfer rates and bandwidth transmission when compared to other cables such as twisted pair cables. Lastly, coaxial cables are fairly cheap in the current market, and their simple construction ensures an easy install. Since it is cheap, you can easily expand it, and it is known for its durability, being the highest amongst other cables.
The first known disadvantage of a coaxial cable is that a single cable failure can bring down a network that it is connected to. However, this can be easily offset by installing a new cable without the hassle of dismantling the network or its parts.
The other con of using a coaxial cable is that it has to be grounded, meaning that a live electric current must be traveling through it in order to work. Lastly, it has been previously mentioned, but the last con of this kind of cable is that it can be thick and stiff, which can make installation much harder.
Types of Coaxial Cables
Just like any other piece of device or gadget, there are various types of coaxial cables that are available to the buying public today. However, the types of coaxial cables are not categorized normally, as its types can be identified by the following parameters:
- The thickness of the cable
- Construction used on the cable
- The cable’s purpose
- The dielectric type used on the cable
- The connector being used by the cable
- The impedance type of the cable
And those are the commonly used parameters when it comes to telling the kind of a coaxial cable. However, when it comes to comparing the impedance being used by coaxial cable, it can be narrowed down to two specific types, namely the 50Ω and 75Ω respectively (the symbol is called ohm).
50Ω Coaxial Cables
This kind of cable is usually used for radio transmissions as it is a good match for both various transmitter antennas and radio transmitters, respectively. Additionally, this kind of cable is used for Ethernet networks that use coaxial cables, as well as for high-frequency digital transmissions.
75Ω Coaxial Cables
This cable type is more common with households, especially with home devices that deal with video/audio transmission (television) and telecommunications (landline). Additionally, it is used by both cable TV and RF video transmission systems (cable TV boxes or cable TV satellite dishes) for its qualities.
Aside from those two types of impedance-type coaxial cables, there are other ones such as 52Ω and 93Ω, although they aren’t commonly used by the public.
RG Classification of Coaxial Cables:
Another way for determining the type of a coaxial cable is through the RG (Radio Guide) classification. This classification type was first used by the military in World War II, and though now obsolete in modern technology, is still widely used by many.
As the classification suggests, it starts with the letters of R and G, which is then followed by a number or pair of numbers (and sometimes a number and letter combination) depending on its type. Thanks to that classification, one can easily identify the purpose of the cable and its characteristics such as core wire diameter, outer diameter, impedance, dielectric type and diameter, and shielding type.
However, the importance of this kind of classification is that one will immediately know what connector the cable is using for its connection. Listed below are the known RG classification types:
Connectors For Coaxial Cables
There are several types of connectors used for coaxial cables in conjunction with its RG classification type. The purpose of the variety of connectors for coaxial cable is for the various connection ports that the cable will be used on. Listed below are the commonly used connectors:
1. BNC connector – is commonly used for RF and video applications. It can handle 4 GHz up to 10 GHz frequencies.
2. N-type connectors – this connector is used for lower microwave frequencies up to 18 GHz and is usually used for various RF applications such as communications and broadcast equipment.
3. SMA Connectors are the commonly used type of connector for various RF applications, handling frequencies from 0 GHz to 24 GHz. It can usually be found with hand-held radio antennas, mobile telephone antennas, microwave systems, and Wi-Fi antenna systems.
4. F-type connectors – the widely used connector type, as it can be found used on TV cables and antenna cables. It can handle frequencies up to 1 GHz.
5. RCA connectors – meant for both audio and video transmissions that handle frequencies up to 10 GHz.
Coaxial Cables as a Speaker Cable?
You might be asking if a coax cable can be used as a speaker cable for your speaker systems. The simple answer to that is a big yes, but you will be needing to convert your existing coaxial cable to a coaxial digital audio cable before proceeding.
The conversion process is just a simple change of the current connector that you have in your cable to a male RCA connector. Of course, it goes without saying that the speakers that you are going to use as the output source must have a female RCA connection port in order for it to work.
Many experts say that when using your coaxial cable as a speaker cable, it should be connected to a powered subwoofer when running the speaker system that you are going to connect the cable with.
Do take note, though, that this kind of setup will bring a huge impedance load to your amplifier, which causes more resistance to your whole setup. Experts advise using this kind of setup moderately.
How to Use Coaxial Cable As a Speaker Wire?
When it comes to converting your current coaxial cable to a usable speaker wire, there are simple steps that you can follow on your end. The first step in the conversion process would be:
Remove Previous Connectors
The majority of coaxial cables that most households use have two connectors connected on each end for connecting to the source and the output device. Remove both of them in this case.
Measure The Length
The common length of standard coaxial cables that you can buy in the market today is around six feet. You need to measure the length of the cable that you will be using for your speaker setup.
Remove The Jacket
You will need to remove the insulation of the coaxial cable in order for it to work as a speaker cable. You can use a ringing tool to do so, or a simple kitchen knife will do.
After the jacket removal, you will be needing to carefully unbraid the shielding as it will be used as wiring for your speakers of choice. Take your time in doing so.
A wire stripper tool will be needed in order to proceed with this step, as you will be needing to get the core wire inside the insulator.
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