Coaxial Cable Guide: Types, Uses, Sizes, TV Connections, and Ethernet Adapters Explained

Published: June 13, 2026

A coaxial cable, often called a coax cable or coax wire, is a shielded electrical cable used to carry high-frequency signals. It is commonly used for cable TV, satellite TV, TV antennas, broadband internet, radio systems, CCTV, and RF test equipment. For most home TV and cable internet connections, the cable you see is usually a 75-ohm RG6 coaxial cable with an F-type connector. For RF equipment, antennas, radio systems, and test instruments, 50-ohm coaxial cables such as RG58, RG8, or RG213 are also common. This guide explains what coaxial cable does, what it looks like, the main types of coaxial cable, common sizes, TV and internet use cases, and how coax differs from Ethernet cable.

What Is a Coaxial Cable?

A coaxial cable is a cable built with one central conductor surrounded by insulation, shielding, and an outer jacket. The word "coaxial" means the inner conductor and outer shield share the same axis. This layered structure helps the cable transmit RF signals while reducing electromagnetic interference. That is why coaxial cable is widely used in applications where signal stability matters, including TV distribution, cable modems, antennas, radio equipment, and measurement systems. The main parts of a coaxial cable are:

Part	What It Does
Center conductor	Carries the signal
Dielectric insulation	Keeps the center conductor separated from the shield
Foil or braided shield	Reduces interference and helps contain the signal
Outer jacket	Protects the cable from wear, moisture, and handling damage
Connector	Connects the cable to a device, wall outlet, antenna, modem, or test instrument

What Does a Coaxial Cable Do?

A coaxial cable transmits high-frequency electrical signals from one device or network point to another. In everyday use, it may carry TV signals from an antenna, cable signals from a wall outlet to a cable box, or broadband signals from a cable network to a modem. Common uses include:

Use Case	Typical Coax Cable
Cable TV	RG6 75-ohm coax
Satellite TV	RG6 75-ohm coax
Cable internet modem	RG6 75-ohm coax
TV antenna	RG6 75-ohm coax
Older analog video or CCTV	RG59 75-ohm coax
Long outdoor TV/cable runs	RG11 75-ohm coax
Radio and RF systems	RG58, RG8, RG213, or similar 50-ohm coax
Lab and test equipment	50-ohm coax with BNC, SMA, or N-type connectors

Coaxial cable is not only a "TV cable." It is a broader RF cable category used anywhere a shielded transmission line is needed.

What Does a Coax Cable Look Like?

A coax cable is usually a round, relatively stiff cable with a single center conductor inside. For TV and cable internet, it often has a threaded metal F-type connector with a small center pin. You may see coaxial cable in these places:

Location	What It Usually Connects
Behind a TV	TV, cable box, antenna, or satellite receiver
Wall cable outlet	Cable TV or cable internet service
Cable modem	Coax from the wall to the modem
Outdoor antenna	Antenna to indoor TV equipment
CCTV installation	Camera to recorder or monitor
RF lab bench	Signal generator, oscilloscope, antenna, or test device

Coax cable is easy to distinguish from Ethernet cable. Coax is round and usually has one center pin. Ethernet cable usually has a rectangular RJ45 plug with eight small contacts. If you are trying to identify a cable behind a TV or modem, the dedicated guide on what a coax cable looks like gives a more visual checklist.

Common Types of Coaxial Cable

Coaxial cables are often identified by an RG number, impedance, size, shielding, and intended application. RG originally came from older military-style cable designations, but today the term is used broadly in commercial cable naming. The most common coaxial cable types are listed below. For a deeper comparison of RG6, RG59, RG11, RG58, and 50-ohm vs 75-ohm cable families, use the full types of coaxial cable guide.

Cable Type	Impedance	Approx. Outer Diameter	Common Use	Key Note
RG6	75 ohm	6.9 mm / 0.27 in	Cable TV, satellite, cable internet, antenna	Best common choice for modern home TV and cable modem connections
RG59	75 ohm	6.1 mm / 0.24 in	Older analog video, CCTV, short low-frequency runs	Higher loss than RG6 at higher frequencies
RG11	75 ohm	10.3 mm / 0.40 in	Long cable TV, satellite, and broadband runs	Lower loss but thicker and less flexible
RG58	50 ohm	5.0 mm / 0.20 in	RF, radio, test leads, older thin Ethernet	Flexible and common for short RF connections
RG8	50 ohm	10.3 mm / 0.40 in	Amateur radio, RF transmission	Larger and lower loss than RG58
RG213	50 ohm	10.3 mm / 0.40 in	RF transmission, radio systems	Durable 50-ohm RF cable
RG174	50 ohm	2.5 mm / 0.10 in	Short internal RF pigtails, small antennas	Very flexible but higher loss

Cable dimensions vary by manufacturer, jacket material, shielding, and construction. Always check the datasheet when exact diameter, attenuation, or connector fit matters.

RG6 Coaxial Cable

RG6 is the most common coaxial cable for modern residential TV, satellite, antenna, and cable internet connections. It is usually a 75-ohm cable and is commonly terminated with F-type connectors. Use RG6 when you need a coaxial cable for:

Application	Why RG6 Fits
Cable TV	Standard home cable distribution
Cable internet modem	Common cable modem connection from wall outlet to modem
Satellite TV	Suitable for high-frequency satellite signals
Digital TV antenna	Lower loss than older RG59 in many home runs
General home coax wiring	Widely available and compatible with F-type connectors

For most home users asking "what is the best TV cable wire?" RG6 is the practical answer. For a TV-focused buying guide, see this breakdown of the best coaxial cable for TV, cable box, satellite, and antenna connections.

RG59 Coaxial Cable

RG59 is a 75-ohm coaxial cable historically used for analog video, CCTV, and older TV installations. It is thinner than RG6 and can be easier to route, but it usually has more signal loss at higher frequencies. RG59 may still be acceptable for short analog video or CCTV runs, but it is usually not the best choice for modern cable internet, satellite TV, or long digital TV runs. If you are replacing or installing cable for TV or internet today, RG6 is usually the better option.

RG11 Coaxial Cable

RG11 is a thicker 75-ohm coaxial cable used when lower signal loss is important over longer distances. It is common in long cable TV, satellite, outdoor, underground, or distribution runs. The tradeoff is flexibility. RG11 is harder to bend and terminate than RG6, so it is usually used for long backbone runs rather than short patch cables behind a TV or modem.

RG58, RG8, and RG213 Coaxial Cable

RG58, RG8, and RG213 are commonly associated with 50-ohm RF applications. They are used with antennas, radio transmitters, receivers, test instruments, and wireless equipment. Use these cables when your equipment specifies 50-ohm coax. Do not substitute a 75-ohm TV coax for a 50-ohm RF system unless the equipment documentation says it is acceptable.

50 Ohm vs 75 Ohm Coaxial Cable

The two most common coaxial cable impedances are 50 ohms and 75 ohms. Matching impedance matters because mismatched cables, connectors, and equipment can cause signal reflections, loss, ghosting in video systems, or measurement errors in RF systems.

Impedance	Common Applications	Typical Cable Types
75 ohm	TV, cable TV, satellite, cable internet, video, antennas	RG6, RG59, RG11
50 ohm	RF, radio, wireless, antennas, test equipment, transmitters	RG58, RG8, RG213, RG174

For TV and cable modem use, choose 75-ohm coax. For radio, RF testing, and many antenna systems, choose the 50-ohm cable specified by the equipment.

Coaxial Cable Sizes and Diameter

Coax cable size affects flexibility, connector compatibility, handling, and signal loss. Larger coaxial cables often have lower loss, but they are also less flexible and harder to install.

Cable Type	Approx. Outer Diameter	Impedance	Typical Use
RG174	2.5 mm / 0.10 in	50 ohm	Small RF pigtails
RG58	5.0 mm / 0.20 in	50 ohm	RF, radio, short test cables
RG59	6.1 mm / 0.24 in	75 ohm	Older video, CCTV
RG6	6.9 mm / 0.27 in	75 ohm	TV, cable internet, satellite
RG11	10.3 mm / 0.40 in	75 ohm	Long cable runs
RG213	10.3 mm / 0.40 in	50 ohm	RF transmission

These values are approximate. Quad-shield, plenum-rated, outdoor-rated, direct-burial, or manufacturer-specific versions can differ in diameter. For connector-fit details and a cleaner diameter chart, see the coax cable sizes and diameter chart.

Coaxial Cable for TV and Antenna Connections

Most modern TV, cable box, satellite, and antenna connections use 75-ohm RG6 coaxial cable with F-type connectors. RG6 is preferred over older RG59 for many higher-frequency digital TV, satellite, and broadband applications. For scenario-by-scenario recommendations, use the dedicated guide to the best coaxial cable for TV and antenna connections.

TV Use Case	Recommended Cable	Connector	Note
Cable TV	RG6 75-ohm	F-type	Most common home TV cable
TV antenna	RG6 75-ohm	F-type or region-specific TV connector	Good for digital TV antenna runs
Satellite TV	RG6 75-ohm	F-type	Use outdoor-rated cable if exposed
Long outdoor run	RG11 75-ohm	F-type	Lower loss over distance
Older analog video	RG59 75-ohm	BNC, RCA, or F-type	Often used for legacy CCTV/video

F-type connectors are widely used for TV, satellite, cable internet, and over-the-air antenna connections. In some regions, IEC-style TV antenna connectors are also common.

Coaxial Cable for Internet

Cable internet service commonly uses coaxial cable to bring broadband RF signals from the wall outlet to a cable modem. After the modem, Ethernet cable or Wi-Fi is usually used to connect computers, routers, switches, access points, and other devices. A typical home cable internet path looks like this:

Cable provider network -> coax wall outlet -> cable modem -> Ethernet/router/Wi-Fi -> devices

The coax cable is part of the access connection from the cable provider. Ethernet usually begins after the modem or gateway. Modern cable broadband systems are based on DOCSIS technology. CableLabs describes DOCSIS 4.0 as supporting up to 10 Gbps downstream capacity and up to 6 Gbps upstream capacity over hybrid fiber-coax networks, although actual service speeds depend on the provider, network, modem, and plan.

Coaxial Cable vs Ethernet Cable

Coaxial cable and Ethernet cable are not the same thing. They may both be used in home internet setups, but they do different jobs.

Feature	Coaxial Cable	Ethernet Cable
Common connector	F-type, BNC, SMA, N-type	RJ45
Cable shape	Round, often stiff, single center conductor	Round or flat twisted-pair cable with multiple conductors
Typical home use	Wall outlet to cable modem, TV, antenna	Modem/router to computer, switch, access point, smart TV
Signal type	RF signals, TV, broadband, antenna, radio	Ethernet network data
Common cable names	RG6, RG59, RG11, RG58	Cat5e, Cat6, Cat6A, Cat7, Cat8

If you have cable internet, the coaxial cable usually brings the service into the modem. Ethernet then carries local network traffic from the modem or router to your devices. The separate coaxial cable vs Ethernet cable article explains when you need a cable modem, MoCA adapter, or ordinary Ethernet cable.

Can You Convert Coax to Ethernet?

You cannot convert coaxial cable to Ethernet with a simple passive plug adapter. Coax and Ethernet use different signaling methods, connectors, and equipment requirements. There are two common ways coax and Ethernet interact:

Device	What It Does
Cable modem	Converts the cable provider's coax broadband signal into Ethernet and/or Wi-Fi for your home network
MoCA adapter	Uses existing in-home coax wiring to create an Ethernet-like network connection between rooms

A cable modem is used for internet service from a cable provider. A MoCA adapter is used inside a home or building when you want to use existing coaxial wiring as a network path.

What Is a MoCA Adapter?

A MoCA adapter is a device that lets network data run over existing coaxial cable inside a home. MoCA stands for Multimedia over Coax Alliance, the industry group behind the standard. MoCA adapters are useful when:

Scenario	Why MoCA Helps
You have coax wall outlets but no Ethernet wiring	MoCA can use the existing coax path
Wi-Fi is weak in another room	MoCA can provide a wired backhaul
You need a more stable link for gaming or streaming	Wired coax networking can reduce reliance on wireless signal quality
Pulling new Ethernet cable is difficult	MoCA may avoid opening walls

MoCA is not the same as a cable modem. A cable modem connects your home to the cable internet provider. MoCA adapters create a local network connection over the coax wiring already inside the home.

How to Choose the Right Coaxial Cable

The right coaxial cable depends on the application, impedance, distance, connector, and environment.

Need	Recommended Choice
Modern TV, cable box, or cable modem	RG6 75-ohm coax with F-type connectors
Outdoor antenna or satellite run	Outdoor-rated RG6, or RG11 for long distance
Long cable TV or broadband distribution run	RG11 75-ohm coax
Older CCTV or analog video	RG59 75-ohm coax may be acceptable
RF radio or test equipment	50-ohm coax specified by the device, such as RG58, RG8, or RG213
Small internal antenna lead	RG174 or another small RF coax, if specified
In-home coax-to-network link	MoCA adapters, not a passive coax-to-Ethernet plug

Before buying, check:

Required impedance: 50 ohm or 75 ohm
Connector type: F-type, BNC, SMA, N-type, RCA, or another connector
Cable length and expected signal loss
Indoor, outdoor, plenum, or direct-burial rating
Shielding level, especially near electrical noise
Device or service provider requirements

Common Mistakes to Avoid

One common mistake is assuming all coaxial cables are interchangeable. A 75-ohm RG6 cable and a 50-ohm RG58 cable may look similar to a non-specialist, but they are meant for different systems. Another mistake is buying a "coax to Ethernet adapter" expecting it to work like a simple plug converter. For networking, you need active equipment such as a cable modem or MoCA adapter. It is also common to reuse old RG59 cable for modern cable internet or satellite TV. It may work in some short runs, but RG6 is usually a better choice for current home TV and broadband installations.

FAQ

What is a coaxial cable used for?

A coaxial cable is used to transmit high-frequency signals for cable TV, satellite TV, TV antennas, cable internet, CCTV, radio systems, wireless equipment, and RF test instruments.

What does a coax cable look like?

A coax cable is usually a round cable with a single center conductor. TV and internet coax cables often have a threaded metal F-type connector with a center pin.

Is coaxial cable the same as Ethernet?

No. Coaxial cable carries RF signals and is commonly used for TV, antennas, cable modems, and RF systems. Ethernet cable carries network data between routers, switches, computers, access points, and other network devices.

What type of coaxial cable is used for TV?

Most modern TV, cable box, satellite, and antenna connections use 75-ohm RG6 coaxial cable with F-type connectors.

What type of coaxial cable is used for internet?

Cable internet connections usually use 75-ohm RG6 coaxial cable from the wall outlet to the cable modem. After the modem, Ethernet or Wi-Fi is used for the local network.

Is RG6 better than RG59?

For modern TV, satellite, and cable internet, RG6 is usually better than RG59 because it generally has lower loss at higher frequencies. RG59 is still used in some older analog video and CCTV installations.

What is RG11 used for?

RG11 is used for longer 75-ohm cable runs where lower signal loss is needed. It is thicker and less flexible than RG6, so it is usually used for long runs rather than short patch cables.

What is the difference between 50-ohm and 75-ohm coax?

75-ohm coax is common for TV, video, cable internet, and satellite systems. 50-ohm coax is common for RF, radio, wireless, antenna, and test equipment. The cable impedance should match the equipment.

Can I convert coaxial cable to Ethernet?

Not with a simple passive adapter. A cable modem converts a cable provider's coax broadband signal to Ethernet or Wi-Fi. MoCA adapters can use existing in-home coax wiring to create a network link between rooms.

What connector does a TV coax cable use?

Most TV, cable box, satellite, and cable modem coax connections use F-type connectors. Some regions and TV antenna systems may also use IEC-style connectors.

Does coax cable size matter?

Yes. Cable size affects flexibility, connector fit, and signal loss. Larger coax cables such as RG11 often have lower loss over long distances, while smaller cables are easier to route but may have higher loss.

About the Author

MOZ Official Authors

The MOZ Electronics engineering team publishes practical guides on electronic components, connector standards, wireless modules, and procurement best practices for engineers and buyers worldwide.