Where Cable Comes From, Part 2: Fiber-Optic and Coaxial Cable

A few weeks ago, I visited our head end here in New York City and took a ton of pictures. I’ll be sharing those photos and accompanying text here over the next several weeks.

For those of you that are wondering, a head end is the place where we actually receive television signals from satellites, clean them up and process them into a stable signal and retransmit them out over the cable network.

Our cable network is made up of a blend of regular coaxial cable and fiber optic cable. We use fiber optic cable for our core network, running it to the node outside the customer’s home. For the last several hundred yards or “last-mile,” we use coaxial cable. Coaxial cable is the same stuff that runs from your wall to your television set. Coaxial cable is the Coca-Cola of the cable world: it’s been around a long time and the formula hasn’t changed that much because it’s reliable, stable, and gets the job done.

Larry Pestana is our Chief Engineer at our NYC head end — you can see him holding a loop of CoAx cable here:

Fiber optic cable is pretty amazing stuff. Data travels through it at the speed of light, with much less signal loss over distance and a much higher bandwidth. Individual fibers are roughly the same width as a human hair, and transmit video data and broadband information all along the same tiny fiber. Here, you see a fiber-optic cable exposed.

The black insulation contains a number of smaller cable wrapped in plastic layers to buffer them from one another and prevent “cross-talk” — data leaking from one fiber to the next. Many fiber optic cables are packed with a water-resistant gel to stop water from seeping in.

Each of those tiny fibers — that one single green one sticking up there, for example — that carries cable video and broadband internet to and from one home. It’s really incredible, when you think about it.

Here’s another type of fiber optic cable. In this one the fibers are packaged into plastic ribbons, each of which contains several fibers that each service a single household.

Each type of cable, fiber and coaxial, has its strengths and weaknesses. Fiber optic cable transmits data much, much faster, with less signal loss, over much greater distances than coaxial cable. It’s generally more reliable. However, restoring it when it gets severed can be very complicated and time-consuming. You have to reconnect each fiber, still the width of a human hair, back to the exact fiber it was severed from for everything to work — very tricky. Coaxial cable is slower, with more signal loss at shorter distances, but cheaper, still very reliable, and much more easy to repair.

The whole purpose of this blog is to “Untangle” the mysteries behind cable and show what an amazing, complicated process the whole thing is. If you’ve got any questions or requests, leave them in the comments and I’ll try and incorporate them into a future post.

Categories: Broadband Penetration/Deployment, Cool Stuff