An RF cable is the coaxial cable that connects an antenna or cable TV service to your television, delivering broadcast channels over radio frequency signals. It’s the round cable with a screw-on connector that plugs into the port on your TV usually labeled “ANT IN,” “RF IN,” or “CABLE IN.” If you’ve ever watched live local channels or used basic cable without a streaming box, an RF cable is what carried that signal to your screen.
How RF Cables Work
RF stands for radio frequency. The cable carries radio frequency signals from a source, either an over-the-air antenna or a cable TV wall outlet, to your TV’s built-in tuner. That tuner decodes the signal into the picture and sound you see on screen. Unlike HDMI cables that carry digital video from a device like a game console or streaming stick, RF cables are specifically designed for broadcast television signals.
The cable itself is a type of coaxial cable, meaning it has a layered construction: a copper wire runs through the center, surrounded by foam insulation, then a layer of metallic shielding (usually aluminum foil and braided copper), and finally an outer plastic jacket. This layered design keeps the signal clean by blocking outside electrical interference from reaching the inner conductor.
What the Connector Looks Like
RF cables use what’s called an F-type connector, a small, round metal fitting with a thin pin sticking out of the center and threads on the outside. You screw it onto your TV’s RF input port by hand. The center pin is actually the exposed copper conductor from inside the cable itself, not a separate piece. If you’ve ever set up a cable box or screwed a coaxial cable into a wall plate, you’ve used an F-type connector.
These connectors come in twist-on and compression varieties. Twist-on connectors are the simplest to install at home. They thread directly onto the stripped end of the cable without any special tools.
What Signals RF Cables Carry
RF cables handle both analog and digital broadcast signals. Analog TV transmitted audio and video as continuous radio waves, similar to how AM/FM radio works. Digital TV, which is now the standard in the United States and most countries, transmits compressed data packets over those same radio frequencies. Your TV’s tuner knows how to decode whichever format it receives.
The three main uses for an RF cable on a TV are:
- Over-the-air antenna signals: Free local channels (ABC, CBS, NBC, FOX, PBS) picked up by an indoor or outdoor antenna.
- Cable TV signals: Channels delivered through a cable provider’s wall outlet, either directly to the TV or through a cable box.
- Satellite TV signals: Routed from a satellite dish to a receiver box, which then typically connects to the TV via HDMI.
RG6 vs. RG59: Which Cable to Use
Not all coaxial cables are the same. The two types you’ll encounter are RG6 and RG59, and for modern TV use, RG6 is the right choice. RG6 has a thicker 18-gauge center conductor and combination foil-and-braid shielding, which lets it handle the higher frequencies that digital TV, cable internet, and satellite signals require (above 50 MHz). It also loses less signal over distance.
RG59 is thinner with a 20-gauge conductor and simpler braided shielding. It was common during the analog TV era and is still used in some security camera setups, but it struggles with the higher frequencies of modern broadcasting. If you’re running a new cable from an antenna to your TV, buy RG6. If your home already has coaxial wiring in the walls, it’s likely RG6 if it was installed after the mid-1990s.
Signal Loss Over Distance
Every foot of coaxial cable weakens the signal slightly. For RG6 cable, the loss depends on the frequency being carried. At lower broadcast frequencies (around 55 MHz), you lose about 1.5 decibels per 100 feet. At higher frequencies used by satellite and upper cable channels (around 1000 MHz), that jumps to roughly 6.5 decibels per 100 feet. At satellite frequencies near 2000 MHz, the loss reaches about 9.3 decibels per 100 feet.
For most home setups where the cable run is under 50 feet, this isn’t an issue. But if you’re running cable from a rooftop antenna through an attic and down to a basement TV, the total distance matters. Every splitter in the line adds more loss on top of that. If you notice pixelation or dropped channels, a signal amplifier installed near the antenna can compensate.
RF Cable vs. HDMI
RF cables and HDMI cables do fundamentally different jobs. An RF cable brings broadcast TV signals into your television. An HDMI cable connects devices like streaming boxes, Blu-ray players, and gaming consoles to your TV with high-quality digital audio and video.
The quality difference is significant. Analog RF signals max out at about 480i resolution, roughly the quality of old standard-definition TV. Even digital over-the-air broadcasts top out at 1080i for most channels. HDMI 2.1, by comparison, supports up to 8K resolution at 60 frames per second with a bandwidth of 48 Gbps, plus advanced audio formats like Dolby Atmos. RF cables simply aren’t designed to deliver that level of detail.
That said, RF cables aren’t obsolete. They’re the only way to receive free over-the-air channels from an antenna without additional hardware. For cord-cutters who want local news, sports, and network shows without a subscription, the RF input on your TV is essential.
Common Signal Problems and Fixes
Poor picture quality on antenna or cable channels usually traces back to one of a few issues with the RF cable or its connections. Electromagnetic interference from nearby electronics, power cables, or large appliances can distort the signal if the cable’s shielding is damaged or insufficient. Running your RF cable parallel to electrical wiring in a wall, for instance, increases the chance of interference.
Loose F-type connectors are another frequent culprit. If the connector isn’t screwed on firmly at both ends, the signal degrades. Corrosion on outdoor connections, cable damage from being bent too sharply, and old RG59 cable that can’t handle modern frequencies all contribute to poor reception. Splitters that divide the signal to multiple TVs weaken it further, with each split roughly halving the signal strength.
If you’re troubleshooting, start by checking that all connections are tight and the cable isn’t visibly damaged. Replace any RG59 cable with RG6. Keep RF cables away from power cords and large motors. For long runs or multiple splits, add a powered amplifier near the signal source rather than near the TV.
NextGen TV and the Future of RF
The latest broadcast standard, ATSC 3.0 (marketed as NextGen TV), still uses RF signals delivered over coaxial cable from an antenna. It supports 4K Ultra HD broadcasting, interactive features, and improved reception on mobile devices. Your existing RG6 cable and antenna will work with NextGen TV, but your television needs a built-in ATSC 3.0 tuner to decode the signal. Many TVs sold before 2020 lack this tuner, so you’d need an external converter box or a newer TV to access these broadcasts.