Different Types of Coaxial Cable: Matching Impedance, Loss, and Installation

If you are comparing different types of coaxial cable, start with the job the cable must do: 50 or 75 ohm, flexible or semi-rigid, indoor or outdoor, short jumper or long feeder, and a connector that fits both the cable and the equipment. The best coax is not the thickest or most expensive one; it is the one whose impedance, loss, shield, jacket, and connector system match the installation.

A coaxial cable is a transmission line built around a center conductor, a dielectric, a shield, and an outer jacket. When buyers ask about “types” of coax, they may mean cable families such as RG-6, RG-59, RG-11, RG-58, low-loss flexible cable, hardline, semi-rigid, twinaxial, or triaxial. They may also mean connector interfaces such as BNC, N, SMA, TNC, F, or 7/16 DIN. Those choices are related, but they answer different questions.

The short answer: match impedance, loss, and installation

For most projects, the first filter is impedance: 75 ohm cable for video, CATV, and broadband-style distribution; 50 ohm cable for radio, antenna, test, and general RF links. The second filter is mechanical: will the cable stay put, bend inside a cabinet, survive weather, or carry a signal over a long feeder run? A cable with strong loss figures is still wrong if its jacket, bend radius, or connector support does not suit the site.

RG-series cables: familiar names, different jobs

RG numbers are not a quality ranking. They are legacy references, and two cables with the same RG number can differ in shield coverage, dielectric, jacket, and loss. Use the RG name to start the conversation, then verify the actual datasheet.

• RG-6: a practical default for modern 75 ohm video and broadband drops when the connector and outlet are compatible.
• RG-59: useful for short video patch runs where a thin, flexible cable matters more than low loss.
• RG-11: chosen for longer 75 ohm runs, but the larger bend radius can turn a simple route into a mechanical problem.
• RG-58: common for short 50 ohm jumpers; it is not the best choice for a long feeder run.
• RG-8: bulkier than RG-58 and often selected when a modest 50 ohm feeder needs lower loss.

RG-59 and RG-6 are often compared, but they serve different priorities. RG-59 is easier to bend and cheaper for short runs. RG-6 is usually the safer default for TV, satellite, and cable-modem drops because its larger construction generally gives lower loss and better shielding.

Low-loss flexible, hardline, and semi-rigid: when loss and stability take priority

Use low-loss flexible cable when you need lower loss without hardline; use hardline or semi-rigid when long runs or fixed geometry matter more than field flexibility. A low-loss foam-dielectric cable often gives the best compromise for antenna and radio installations because it bends like a cable but loses less signal than a thin RG-style cable. Hardline goes further with a rigid outer conductor and is common where long feeder runs and stable performance matter more than easy routing. Semi-rigid cable is formed into a fixed shape and is usually chosen for internal RF assemblies or microwave modules where repeatable geometry matters more than serviceability.

These families also change connector planning. An N-type interface is common on weatherized outdoor feeder runs, while SMA is common on compact modules, test ports, and smaller assemblies. The cable and connector must share the same impedance and be mechanically compatible; a 50 ohm connector on a 75 ohm cable is not a harmless mismatch.

N RF Coaxial Connectors for Outdoor and Cable AssembliesReview N-series options by impedance, mounting style, cable compatibility, and environmental sealing before specifying weatherized feeder connectors and assemblies.View Product →

For a feeder project, confirm the connector body style, sealing method, and cable entry size before ordering. The cost of a wrong connector usually shows up later as rework, a water path, or an intermittent shield contact.

Twinaxial and triaxial: related cable types with different shielding logic

Twinaxial and triaxial are specialized cable types, not substitutes for standard coax. Twinaxial cable uses two conductors inside a shared shield, usually for balanced or specialized digital links. Triaxial cable adds another shield layer for guarded or low-noise measurements. If a system calls for twinax or triax, the connector, termination, and grounding plan are part of the cable choice, not an accessory.

Cable type is only half the choice: connector interface and adapter planning

The connector interface is not a cosmetic choice; it must match the cable, the equipment, and the environment. BNC is common for test and video, N for rugged outdoor RF, SMA for compact microwave and test ports, TNC for threaded vibration-resistant links, F for consumer video, and 7/16 DIN for high-power site equipment. Mating style, gender, polarity, and mounting method all matter.

SMA RF Coaxial Connectors for Compact and Test ApplicationsCompare SMA configurations by frequency, polarity, mounting, and cable compatibility for compact microwave, test, and antenna connections.View Product →

Adapters should be treated as part of the RF path, not as a way to fix a specification error. Each adapter adds loss and another mechanical interface. Use them to bridge a genuine interface mismatch, not to compensate for the wrong cable. For a broader view of the connector side of the selection, review the coaxial connector product range and plan the cable, connector, and adapter as one assembly.

RF Coaxial Adapters for Interface Conversion and ExtensionUse inter-type, within-type, and reverse-polarity adapters to bridge genuine connector mismatches without treating them as impedance converters.View Product →

When a design mixes 50 ohm and 75 ohm equipment, stop and correct the architecture. A passive adapter cannot turn a 75 ohm system into a 50 ohm system, and the mismatch will show up as return loss, level error, or unstable performance.

A practical selection checklist for buyers

Use a short specification checklist before requesting samples or quotes; it prevents the most common mismatch between a low-cost cable and an expensive connector.

1. Confirm impedance: 50 ohm for most RF links, 75 ohm for video and broadcast distribution.
2. Estimate frequency and run length: higher frequency and longer runs punish loss, so move to a larger or low-loss cable.
3. Check the environment: outdoor, burial, plenum, UV, oil, and flexing requirements may change the jacket and shield.
4. Match connector to cable: series, gender, polarity, mounting, and cable entry size must all be correct.
5. Review bend radius and routing: hardline and semi-rigid may not fit the route you have in mind.
6. Ask for test data: insertion loss, return loss, shield effectiveness, and jacket ratings are more useful than a family name.

For a more detailed selection walkthrough, read the RF coaxial connector guide.

Common failure points and purchasing risks

Most coax failures are not caused by the cable family alone; they come from a mismatch between cable, connector, installation, and environment.

• 50/75 ohm mismatch: the assembly may still show a signal, but return loss and level accuracy suffer.
• Poor shield termination: a connector that does not contact the shield properly can turn a good cable into an intermittent antenna.
• Water ingress: outdoor connections need proper sealing; tape and a boot are not a substitute for a weatherproof interface.
• Wrong jacket: indoor PVC cable used outdoors, or a stiff cable forced into a tight bend, can fail after installation.
• Adapter stacking: each extra adapter adds loss and a mechanical joint that can loosen or corrode.

For a long feeder run, the cheapest cable is rarely the lowest total cost. Rework, signal loss, and repeat site visits usually cost more than the difference between a basic cable and a properly specified low-loss cable.

FAQ

What are the main types of coaxial cable?

The main families include RG-6, RG-59, RG-11, RG-58, low-loss flexible cable, hardline, semi-rigid, twinaxial, and triaxial. Each family is a starting point; impedance, shield, jacket, and connector details determine whether it fits a specific installation.

Is RG-6 better than RG-59?

For modern TV, satellite, and cable-modem drops, RG-6 is usually the better default because it has lower loss and better shielding. RG-59 can still be useful for short video runs where its smaller bend radius and lower cost matter.

Which coaxial cable is best for internet service?

For a cable-modem drop, use a 75 ohm cable specified for the service, commonly RG-6 with a suitable shield and outdoor rating where needed. Do not substitute a 50 ohm RF cable just because it has a similar connector.

Can coaxial cable be used outdoors?

Yes, but only with a jacket and connector system rated for the environment. UV exposure, moisture, temperature, and sealing matter more outdoors than the RG number alone.

Does cable length affect signal quality?

Yes. Loss rises with length and frequency. A cable that works on a short bench jumper may be a poor choice for a long feeder run; check insertion loss at the highest frequency of interest.

Are coaxial cable types the same as connector types?

No. Cable type describes the transmission line; connector type describes the mating interface. A complete assembly needs both to match, along with the right gender, polarity, and mounting style.

The practical answer to different types of coaxial cable is to choose by system impedance, frequency, run length, environment, and connector interface, then verify the actual datasheet. RG-6 and RG-59 are not interchangeable by name, hardline and semi-rigid solve different mechanical problems, and a low-cost adapter cannot repair a mismatched RF path. A short checklist and a sample evaluation will usually reveal more than a family label.