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Copper Coaxial Cables

Coaxial cable is built from a layered structure — center conductor, dielectric insulator, foil shield, braided shield, and outer jacket — designed to carry data while blocking electromagnetic interference. Common coaxial standards include RG6, RG11, and RG59, with F-type and BNC connectors among the most widely used termination options.

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About this video

Coaxial cable is constructed from a series of concentric layers, each serving a distinct purpose. At the core is the center conductor, which carries the actual data signal. Surrounding it is a dielectric insulator that prevents electrical current from passing between the conductor and the outer shielding layers. Two shielding components — a foil shield and a braided shield — work together to protect the signal from electromagnetic interference, keeping data transmission clean and reliable. The entire assembly is wrapped in an outer jacket that keeps all internal components safely insulated from the environment. Coaxial cables are categorized using RG ratings, a designation that reflects differences in conductor size and other physical specifications. RG6, RG11, and RG59 are among the standards still encountered in the field, each carrying its own performance characteristics and use cases. In most modern network environments, Ethernet cable has largely replaced coaxial, though coaxial remains common in ISP infrastructure and certain legacy installations. A related cable type, twinaxial cable, shares the same shielded outer construction but houses two separate conductors at its core, allowing it to carry two distinct data streams. Two connector types dominate coaxial cable termination. The F-type connector features a threaded design that screws securely onto compatible ports, providing a tight, stable connection well suited to permanent installations. The BNC connector uses a push-and-turn mechanism — sliding onto the port and locking into place with roughly a quarter turn — making it faster to connect and disconnect. Both connector types are widely recognized in the industry and appear across a range of equipment and cabling scenarios.

What you'll learn

What's covered

Coaxial Cable

Aligned to

CompTIA Network+
1.5 Compare and contrast transmission media and transceivers.
CompTIA A+ Core 1
3.1 Explain basic cable types and their connectors, features, and purposes.
Cisco CCST Networking
3.1 Identify cables and connectors commonly used in local area networks.
Cisco CCNA
1.3 Compare physical interface and cabling types
Cisco CCST IT
2.3 Assist end users in locating, identifying, and understanding ports and cables

Key terms

Coaxial Cable
A type of electrical cable consisting of a center conductor, dielectric insulator, foil shield, braided shield, and outer jacket used to transmit data signals.
Center Conductor
The innermost component of a coaxial cable through which data signals are transmitted.
Dielectric Insulator
A non-conductive layer surrounding the center conductor in a coaxial cable that prevents electrical interference between the conductor and the outer shields.
Foil Shield
A thin metallic layer wrapped around the dielectric insulator in a coaxial cable that protects the signal from electromagnetic interference (EMI).
Braided Shield
A woven metallic layer surrounding the foil shield in a coaxial cable that provides additional protection against electromagnetic interference.
Outer Jacket
The outermost protective covering of a coaxial cable that encases all internal components and prevents exposure of conductors.
F-Type Connector
A threaded coaxial cable connector that is secured by screwing it onto the port, requiring multiple rotations to fasten tightly.
Bayonet Neill-Concelman
BNC
A type of quick-connect coaxial cable connector with a bayonet locking mechanism, used in older 10BASE2 Ethernet networks and video/RF equipment. BNC connectors are largely replaced by RJ-45 in modern LAN environments.

Transcript

What Makes Up a Coaxial Cable

First of all, this center part right here is the conductor. That's where the data is actually being transferred across, so that's the center conductor.

Then we have a dielectric around the outside here. That's an insulator — it insulates it, it makes sure that no electricity is flowing between that center conductor and the outside foil.

So then we have the outside foil here. That's a foil shield, and it protects it from some of the EMI that will be around this device. That's what's protecting the data, so the data can be cleaner as it comes through that center conductor. And then we've got a braided shield around the outside, so we've got kind of two shielding components here. And then finally we've got the jacket along the outside, so that none of these conductors are exposed. So that's coaxial cable right there.

Coaxial Standards

There are a lot of different types of coaxial cables out there, and we don't need to know all of the differences. Just know that things like the size of the conductor, and some other variables in here, are going to change and are going to determine which standard is out there, and they're all going to have their pros and their cons. I'm not going to name them all, because the nuances between those differences are really not that important.

Just know that one of the things that defines these out there is the radio guide, or RG, which will define the characteristics for each one of these types. RG6 is one of those. RG11 and RG59 might be some of those that you still see out there. For a lot of your cables, though, you're going to be probably working a lot more with Ethernet cables within your networks, unless you're working for some of the big ISPs that have these cables that are running there.

Then the other thing is, occasionally we'll see twinax cable out there, or twinaxial cable, and that's where you have multiple conductors in the middle, or two conductors in the middle. So it's the same type of cable with the shielding on the outside, but this inside part will have two different strands to it, and we'll have two different conductors going in there for the data side of it.

Connectors

There's also lots of different types of connectors out there as well. We don't need to know all of the different types of connectors, but two that I'm going to mention are the F-type of connector and the BNC type.

The F-type connectors are the ones that have threads on the inside. You can see threads that are on there right now. Those are the ones that you're going to put into the equipment and you're going to be turning quite a few times to get it fully screwed on tight. So that's the F-type.

Then you have the BNC type of connectors. What they do is, on the other end of it, it will slide onto there, and there'll be probably about a quarter of a turn or a third of a turn to actually lock it into place. So there's the hole right there, and then a slot right here. That slot will go over kind of a part that sticks out a bit. It'll slide on, you'll put a little quarter of a turn in there, and they'll snap into place where this little hole is right there. So that's the type you'll push on and do a little quarter of a turn to make it stick.

F-type connectors and BNC are two of the most common types of connectors.

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