CATV cable is coaxial cable originally designed to deliver television signals to homes, and it now serves as the backbone for cable internet, security cameras, and other video applications. The acronym CATV stands for Community Antenna Television, a name dating back to 1948 when communities in areas with poor over-the-air reception built large shared antennas on hilltops and ran coaxial cable from them down to individual houses.
Today, that same type of cable carries far more than TV channels. Here’s what it actually does and how it fits into modern homes and networks.
Cable Television: The Original Purpose
CATV cable was built to solve a simple problem: people living in valleys, mountainous areas, or far from broadcast towers couldn’t pick up TV signals with a rooftop antenna. Starting in 1948 in the United States and Switzerland, operators installed powerful community antennas in high locations and distributed the signal through coaxial cable to nearby homes. Each TV channel occupies a 6 MHz slice of bandwidth, and early cable systems could carry signals up to about 300 or 350 MHz, enough for a few dozen channels.
Over the decades, cable systems expanded their capacity significantly. Systems installed in the 2000s commonly supported up to 450 MHz, while newer builds pushed to 550 MHz and then 800 or 860 MHz. More bandwidth means more channels, plus room for digital video, on-demand content, and eventually internet data sharing the same cable.
High-Speed Internet Over Coaxial Cable
The biggest modern use of CATV cable is delivering broadband internet. In 1997, CableLabs released the first version of DOCSIS (Data Over Cable Service Interface Specification), a standard that allowed internet data to travel alongside TV signals on existing coaxial infrastructure. That single innovation turned every cable TV network into a potential internet provider without rewiring neighborhoods.
The current widespread standard, DOCSIS 3.1, makes 1 Gbps cable broadband available to roughly 80% of U.S. homes. That’s fast enough for 4K video streaming, multiplayer gaming, and video conferencing running simultaneously. The next generation, DOCSIS 4.0, pushes capacity to up to 10 Gbps downstream and 6 Gbps upstream, a fourfold increase in upload speed. Lab demonstrations have already achieved 14 to 16 Gbps of aggregate downstream capacity across multiple vendors.
Beyond raw speed, newer standards also tackle latency. Low Latency DOCSIS, introduced with version 3.1 and carried forward into 4.0, reduces the delay that matters for cloud gaming, video calls, and real-time collaboration tools.
How CATV Cable Fits Into Modern Networks
Most cable networks today don’t run coaxial cable the entire distance from the provider to your house. Instead, they use a Hybrid Fiber-Coaxial (HFC) architecture. Fiber optic lines carry signals from the cable company’s central facility to a neighborhood node serving 500 to 2,000 subscribers. At that node, a laser receiver converts the optical signal back into an electrical one, and coaxial cable handles the “last mile” into each individual home.
This split design plays to each cable type’s strengths. Fiber handles long distances without signal degradation, while coaxial cable is cheaper to install for the short runs into houses and works with the equipment already inside most homes. Your cable modem, TV box, or DVR connects to this coaxial line through a threaded F-type connector, the same screw-on fitting that’s been standard on cable equipment for decades.
Security Cameras and Surveillance
CATV-style coaxial cable has long been used to connect analog security cameras. For years, buildings were wired with RG-59 or RG-6 coax running from each camera back to a central recording device. The cable carried the analog video signal reliably over moderate distances with minimal interference.
Modern security systems have largely shifted to IP-based cameras that use Ethernet cabling. But many older buildings still have coaxial wiring in the walls, and ripping it out is expensive. Power-over-Coax (POC) adapters solve this by converting the connection at each end: one adapter connects to the IP camera, another connects to the Ethernet switch, and the existing coax cable carries the data in between. Analog camera systems used BNC-style connectors rather than the F-type connectors found on TV equipment, and many POC adapters accommodate this older connector style.
RG-6 vs. RG-59: Which Cable for Which Job
Not all CATV cable is identical. The two most common types are RG-6 and RG-59, and while both have 75-ohm impedance, they differ in ways that matter for performance.
- RG-59 has a thinner center conductor, a thinner insulating layer, and typically only a single braided copper shield with no foil layer. It works fine for short cable runs and was the standard for analog video, including older security camera installations.
- RG-6 has a larger center conductor, thicker insulation, and at least two shielding layers (foil plus braid). Some versions have three or four shielding layers. This makes RG-6 better at carrying higher-frequency signals over longer distances, which is why it’s the standard for cable TV, internet, and satellite installations today.
The extra shielding in RG-6 reduces both high-frequency signal leakage and low-frequency interference from nearby electronics. For any new installation involving television or internet service, RG-6 is the right choice. RG-59 is mainly found in legacy setups or very short video connections.
Signal Loss From Splitters
If you’re running CATV cable to multiple rooms, you’ll likely use a splitter, and every split costs you signal strength. A two-way splitter introduces roughly 3.5 dB of loss on each output port. A four-way splitter doubles that to about 7 dB per port. In practical terms, splitting the signal too many times can cause pixelation on TV channels or slower, less reliable internet speeds. If you need to feed four or more rooms, a powered signal amplifier before the splitter can compensate for the loss.
Why Shielding Matters
The coaxial design of CATV cable exists for one core reason: protecting the signal from electromagnetic interference. The center conductor carries the signal, surrounded by an insulating layer, then one or more metal shields, then an outer jacket. When the shielding is intact and properly connected, it can block 100 dB or more of outside electromagnetic noise. That’s the difference between a clean picture and one full of static, or between a stable internet connection and one that drops out when someone runs a blender in the kitchen.
This is also why connectors matter. The F-type connectors used on CATV cable should make firm, complete contact. Loose or corroded connectors break the shielding barrier and let interference in. Compression-style connectors, which squeeze onto the cable for a tight mechanical fit, are more reliable than the older crimp or push-on types. Whether you choose nickel or gold plating on the connector makes no measurable difference for standard cable TV and internet signals.