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What Is Coaxial Cable and How Is It Used?

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Coaxial cable is commonly used by cable operators, telephone companies, and internet providers worldwide to convey data, video, and voice communications to customers. It has also been used extensively within homes.

Coaxial cable has been around for a long time as a technology (since the early 20th century) and has many singular advantages for reliable, accurate transmission.

It also has limitations that will cause it to be replaced in some cases by fiber optic cable, category cable or, sometimes, by wireless signals.

The key to coaxial cable's success has been its shielded design, which allows the cable's copper core to transmit data quickly, without succumbing to interference or damage from environmental factors.

The Two Most Common Cable Sizes are RG-6 and RG-11:

  • RG stands for "radio grade", they are also known as RF cables, which stands for "radio frequency".
  • RG-6 cable is used for drops shorter than 150 feet.
  • RG-11 cable is used for longer drops due to the increased performance over lengths more than 150 feet.
  • Broadband cables used in homes have an impedance of 75 ohms.

What is Coaxial Cable?

Coaxial cable is a type of cable that has an inner conductor surrounded by an insulating layer, surrounded by conductive shielding (outer conductor), and a protective outer jacket. The diagram below illustrates the construction of a typical cable. Electrical signal flows on the center conductor. 

10 09 08 07 06 05 04 03 02 01
  1. Center conductor - copper-clad steel.

  2. Center conductor bond - clean stripping polymer is utilized to block moisture migration.

  3. Dielectric - polyethylene, closed-cell foam with high VP providing mechanical stability.

  4. First outer conductor - an aluminum-polymer-aluminum tape securely bonded to the dielectric.

  5. Second outer conductor - a 34 or 36 AWG aluminum braid

  6. Third outer conductor - an additional aluminum-polymer-aluminum tape is used in tri-shield and quad-shield constructions to further enhance HF shield isolation before and after flexure.

  7. Fourth outer conductor (optional) - an additional 34 or 36 AWG aluminum braid is used in quad-shield constructions to further improve LF shield isolation in extreme RF noise environments.

    • Indoor and aerial - a non-drip material designed to prevent corrosion of metallic components of the cable.
    • Underground - a flowing compound able to prevent moisture migration.

      Corrosion resistant protectant

  8. Jacket - a UV stable outer jacket of either polyethylene (PE) or flame retardant polyvinyl chloride (PVC) to protect the core during the life of the cable.

  9. Integral messenger - a galvanized, carbon steel wire support member attached to the cable by a separable web.

Which Is Better: Coaxial Cable or Fiber Optic Cable?

Both types of cable can be used for carrying video, audio, and other forms of data, and both can offer you distinct advantages and disadvantages in setting up your network.

Deciding which is best for your situation depends on the distance of your connection and the amount of data you will send. Fiber optic cables carry a signal for several miles before needing a repeater. Signal losses are higher in coax cable, so you should use it for shorter distances. Fiber optic cables carry far more information, and it is also more expensive. Fiber optic cables are found less frequently in residential and consumer settings than coaxial cables, but fiber networks continue to grow in networks around the world.

Coax cables are easy to install and very durable. Because fiber has higher and faster data transfer than coax, they are best used for professional networks or multi-dwelling units (MDUs), such as those found within a business campus, university or apartment complex. If you are working on a home installation or medium-capacity data transfer network, then most would choose to install with coax cable.

Regarding the cost of fiber vs. coax, fiber is typically higher upfront with a long lifespan. After installation, the price for dedicated internet access over fiber will also be higher than a shared cable internet connection. It's important to weigh the options before making this critical decision that will impact your network service for the foreseeable future.

This post was originally published on March 14, 2017 and updated on October 6, 2022.

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