In this guide
A coaxial cable is used to carry high-frequency RF signals — such as cable TV, over-the-air antenna feeds, satellite, and broadband internet — with low signal loss and strong protection against electrical interference.
- Cable is the correct impedance (75Ω for TV/satellite, 50Ω for radio)
- Connectors are properly fitted and impedance-matched (e.g., F-type)
- Cable run is appropriate length with no sharp bends
- Quad-shield or dual-shield is used in high-interference areas
- Dielectric is damaged or connectors are poorly crimped
- Impedance is mismatched, causing signal reflections or ghosting
- Cable is excessively long without a signal amplifier
- Moisture has entered the connector or jacket
How a Coaxial Cable Is Built
A coaxial cable has four layers: a central copper conductor, a dielectric insulator, a metallic shield (braid, foil, or both), and an outer plastic jacket. The signal travels along the inner conductor while the shield keeps electromagnetic interference (EMI) out. Both conductors share the same geometric axis — that is where the name “coaxial” comes from.
You can read the full technical breakdown on the Wikipedia coaxial cable article.
Common Uses for Coaxial Cable
- Cable TV and satellite TV — delivers video signals from a wall outlet or dish to your TV or set-top box
- Over-the-air antenna — connects a roof or attic antenna to a TV tuner
- Broadband internet (cable modem) — carries DOCSIS internet signals from your ISP into the modem
- Amateur and CB radio — runs RF signal between a transceiver and antenna
- CCTV and security cameras — transmits analog or HD-SDI video over longer distances
Coaxial Cable Types at a Glance
| Setup | Works? | Need | Note |
|---|---|---|---|
| Cable TV / satellite | Yes | RG6, 75Ω, F-type | Standard in most homes |
| Long antenna run (100 ft+) | Yes | RG11 | Lower attenuation than RG6 |
| Short antenna run | Yes | RG6 or RG59 | RG59 acceptable under 25 ft |
| High-interference environment | Yes | Quad-shield RG6 | Extra shielding layers block EMI |
| Mismatched impedance | No | Correct cable type | Causes reflections and signal loss |
Why Impedance Matching Matters
Coaxial cables come in two main impedances: 75Ω for home TV and broadband, and 50Ω for radio transmitters. Mixing the two causes signal reflections that degrade picture quality or reduce data throughput. Always check your device’s required impedance before buying a cable.
If you are also connecting a display device and need to know whether different signal standards can bridge together, see our guide on whether USB-C can connect to HDMI for a comparable compatibility breakdown. For troubleshooting modern display cables, our article on why USB-C to HDMI is not working covers similar signal-mismatch issues.
When Coaxial Cable Fails
The most common failure points are damaged connectors, sharp bends in the cable that distort the dielectric, and moisture getting into outdoor connections. A cable that is too long without amplification will also lose signal strength gradually. For very high-frequency applications, standard dual-shield cable may not provide enough EMI rejection — quad-shield is the safer choice.
Bottom line: A coaxial cable is the standard choice for carrying RF signals in homes and professional AV setups. Use RG6 with F-type connectors at 75Ω for TV, satellite, and cable internet, match your impedance, protect outdoor connections from moisture, and upgrade to RG11 or quad-shield when runs are long or interference is high.