Most people have interacted with coaxial cables at some point even though many may not realize it. Improving your understanding of coaxial cables will be helpful to you. This guide covers the things you need to know about coaxial cables so you can make informed decisions.
1. What Are Coaxial Cables?
Coaxial cables are a means of relaying high frequency electrical signals with minimal signal loss. The main components of the coaxial cable are as follows:
- Inner Core: A single wire made from copper or copper-coated steel forms the central core that carries a high frequency signal.
- Dielectric: A thick plastic dielectric insulator surrounds the inner core to ensure a consistent gap between the inner core and the outer core.
- Outer Core: The outer core comprises a metal shield that wraps around the insulator. It comprises woven aluminum, copper or other metal. The outer core cancels external electromagnetic interference that would otherwise interfere with signal transmission.
Insulation: The last layer is a flame-retardant polyvinyl chloride (PVC) or polyethylene (PE) outer jacket insulating the entire cable.
2. How Do Coaxial Cables Work?
Coaxial cables carry a signal through the copper or copper-coated steel inner core. The outer core is a thin sheath or braided copper mesh that acts as the ground and dissipates stray interference. Both the inner and outer cores create a magnetic field. The insulator between them prevents the signals in the two cores from canceling out or otherwise interfering with each other. It also protects the central core from external magnetic interference.
A key characteristic of coaxial cables is the strict adherence to cable materials and dimensions. This ensures the attributes of the cable are predictable and constant irrespective of manufacturer.
Several factors determine the quality of signal in a coaxial cable. These include:
- The outside diameter of the inner core
- Inside diameter of the outer core
- Nature of the dielectric insulator, including magnetic permeability
- Length of the cable
- The thickness of the cable
3. Types of Coaxial Cables
More than 50 coaxial cable standards exist with some designed for narrow, highly specific applications. However, the following three standards are the most common.
The RG6 is the most common nonindustrial coaxial cable standard. RG is short for ‘radio guide’. With an impedance of 75 Ohm and an outside diameter of 6.90mm, it has broad commercial and residential applications including cable television and Internet connectivity. It is a resilient, thick, and reliable cable with a thicker core than most other coaxial cable types. It also has higher-quality shielding and thicker insulation which protects the signal from external interference as well as physical damage.
The RG59 is relatively similar to the RG6 but is an older standard. There are some notable differences. With an outside diameter of 6.15mm, the RG59 is thinner than the RG6. While you can use it for cable modems and satellite television, it is most ideal for security cameras such as closed-circuit television (CCTV). The thinner, more flexible coaxial cables augur well for CCTV installation since there is often not much room for installers to use. Do not use the RG59 for signal frequencies exceeding 50 MHz. Opt for the RG6 instead.
The RG11 is more recent than both the RG6 and RG59. It has an outside diameter of 10.30mm. Like the RG6, it has an impedance of 75 Ohm. It is however a higher gauge and longer range coaxial cable. You can use it for TV antennas, HDTV, cable television, and video distribution. Signal deterioration starts at about 100 feet for the RG59 and RG6 but begins at about 200 feet for the RG11.
4. Coaxial Cable Connectors
You have to fit a coaxial cable with a connector on each end so you can plug it into the target device. Connectors safeguard the signal’s integrity as it passes from the coaxial cable to the device. The most suitable connector depends on where you are connecting it to. How far the signal power source is from the device also matters. While there are several types of coaxial cable connectors, the following are the most common.
Bayonnet Neil-Concelman (BNC) Connector
You can use BNC connectors to connect test instruments and RF equipment as well as relay video, television, and signals radio. BNC connectors best operate at a signal frequency below 4GHz.
Threaded Neil-Concelman (TNC) Connector
The TNC connector is small and weatherproof. You can deploy it on RF/antenna and mobile phone connections. It is similar to the BNC with the main difference being that the TNC connector has threading and runs at a signal frequency of up to 12GHz.
Subminiature Version A (SMA)
The SMA is a small connector that relies on a screwing mechanism for coupling. Applications include mobile phone antennas, handheld radios, and microwave systems. It operates at a signal frequency of up to 18Ghz.
Subminiature Version B (SMB) Connector
SMB connectors have widespread use in telecommunication and industrial microwave/RF equipment. They have a simple coupling design that features a snap-on mechanism that readily couples uncommon connections.
QMA (QMA) Connector
QMA connectors are similar to the SMA and SMB but include a quicker and more permanent locking feature. For this reason, you can use them in commercial and industrial environments.
7/16 Deutsches Institut für Normung (7/16 DIN) Connector
The 7/16 DIN is a German standard. You can use this threaded connector in situations where durability and water impermeability are important. It is especially useful for broad communication and base stations.
Micro Coaxial (MCX) Connector
MCX connectors are the smallest. They are most ideal for mini coaxial cables or situations where there are severe space constraints. Applications include wireless, TV tuners, digital cellular, and GPS. They have a snap-on mechanism for easy coupling.
The F-type is the most widely used connector and is applied to residential wiring for satellite television, cable television, cable modems, and coaxial audio cable. It usually goes with the RG6 or RG59 cable type.
For the thick coaxial cables common in certain commercial and industrial environments, you can use the large N-type connector.
5. What Can You Use Coaxial Cables for?
The following are the main uses of coaxial cables.
Coaxial Cables for Internet
Internet service providers historically used coaxial cables as a form of Ethernet with speeds as high as 10Mbps. However, their use as a medium for Ethernet connectivity in commercial environments has declined in favor of twisted pair cabling. That said, cable copper-based broadband Internet runs on the coaxial cable and remains in widespread use. An Internet service provider connects an RG6 cable to your home or office. They plug it into a cable modem or router. You can thereafter run a cable to your computer or television for Internet access or cable television viewing.
Coaxial Cables for TV
If you have cable television, your home has a coaxial cable installed. Cable TV companies use RG6 coaxial cables to connect satellite antennas to homes and offices. You can use coaxial cables for connecting your digital converter box or TV to a personal antenna.
Coaxial Cable for HDTV (High-Definition Television)
The most appropriate coaxial cable for high definition television is the RG11. These higher gauge HD coaxial cables have the larger capacity needed for voluminous data transfer.
Coaxial Cable for CCTV
While you can use the RG6 for closed-circuit television, the RG59 is more suitable. The RG59 is thinner and less stiff so you can better maneuver it into narrow spaces.
Coaxial Cable for Video
You can use both the RG6 and RG59 for video. However, the RG6 is the better option for digital video while RG59 could work well with analog video.
6. How to Join Two Coaxial Cables?
There will be times when your coaxial cable breaks or is not long enough. You have the option of buying a new one. But that is a cost you do not necessarily have to incur. You can join two coaxial cables and therefore minimize your expenses. To do so, you will need a coaxial cable coupler. Here’s how the process goes.
Cut the outer layer of each cable on the ends you would like to join together. Do so for a length of 12mm from the cable tip. For both cables, fold backward the metal sheath or braid that forms the outer core so you can expose the dielectric material.
Next, cut the dielectric leaving just 3mm of insulation. Take an F-type plug and screw it onto the metal sheath you had folded backward. Twist firmly but carefully until the dielectric is in position. You will now see about 2mm of the central core conductor at the end of the plug. In case it exceeds 2mm, trim it until it does.
Once done, connect both cables to the coupler on each end, then tighten in position.
7. Coaxial Cables or Fiber Optic Cable: Which Do You Need?
Both coaxial and fiber optic cable can carry audio, video, and other electronic data. There are important differences, though.
- Fiber optic can relay a signal over several miles before it requires a repeater. Coaxial cables have higher signal losses over similar distances.
- Fiber optic cables transmit data at the speed of light and have a much higher data-carrying capacity than coaxial cable. Therefore, you will find them in businesses, colleges, hospitals, government offices, and similar corporate environments. On the other hand, you are better off going with coaxial cable if you are contemplating home installation.
- Coaxial cable is significantly cheaper than fiber optic.
8. Know More About Coaxial Cables
What is a Coaxial Splitter?
You can use a coaxial cable splitter when you want to plug multiple devices into one cable. You attach the splitter to the cable to facilitate multiple connections via a single coaxial cable.
What is a Coaxial Port?
A coaxial port is the female RCA connector on a device. Manufacturers often label them as ‘coaxial,’ ‘digital in’ or ‘digital out’ and color-code them black or orange.
What is a Coaxial Cable Extender?
You can use a coaxial extender to inject power and extend signal transmission over a coaxial cable. It is a convenient tool for relaying video and power to remote device installations. It is especially useful when remote devices are beyond the maximum signal distance specifications of the cable.
Before you purchase a coaxial cable, there are several things you need to take into consideration. Is it for residential, commercial, or industrial applications? How are you going to use it? How far is the signal power source from the target device? What is your budget? Once you are clear on why you need the cable, you can better identify the most suitable one. If you have any questions or are looking to buy quality coaxial cables and related accessories, contact us at no cost.