What Type of Coaxial Cable for Internet? | The Right Coax for 2026 Speeds

A flickering connection or slow speed is rarely your plan; more often it’s the cable connecting the wall to your modem. The wrong coaxial cable — usually old, thin RG59 — can choke a 500 Mbps plan down to a crawl because it wasn’t built for the high-frequency signals DOCSIS 3.1 and 4.0 rely on. Here is exactly which cable to buy, what the specs actually mean, and how to install it without leaving speed on the table.

RG6 vs RG59: What Changes With Broadband

The difference between these two cables is not a marketing game. RG6 is built for modern high-frequency broadband (above 50 MHz, well into the GHz range), while RG59 was designed for low-frequency analog video and older cable TV. The Premier Broadband guide for 2026 calls RG6 the standard for DOCSIS 3.1 and 4.0 modems.

RG59 lacks the dual shielding and thicker foam dielectric that prevent signal loss at the frequencies a cable modem uses. If you’re connecting a modem to a 250 Mbps or faster plan, RG59 will often be the weakest link in the chain.

RG6 Coaxial Cable: What the Spec Sheet Actually Means

Not all RG6 is created equal. The key numbers to look for determine whether the cable will hold up over a home run or degrade quietly.

• Impedance: 75 Ohms. This is non-negotiable for video and broadband equipment. A 50-Ohm cable (used for radio antennas or wireless gear) will cause an impedance mismatch and wreck the signal.
• Center conductor: 18 AWG, solid bare copper or copper-clad steel. Bare copper bends better and conducts more cleanly over long runs.
• Dielectric: Foam polyethylene, 0.180 inches thick. The thicker foam is what separates RG6 from RG59 and gives it the high-frequency capability.
• Shielding: Dual-layer — an aluminum foil tape that gives 100% coverage plus a braided aluminum shield. This blocks interference from nearby power lines, appliances, and neighbor signals. RG59 often has only the braid.
• Frequency rating: Optimized for signals above 50 MHz, supporting the GHz-level frequencies used by cable TV, satellite, and internet modems.

Choosing Between RG6 Variants: Plain, Flooded, and Plenum

The right RG6 depends entirely on where the cable runs. Using the wrong jacket type can violate safety codes or let moisture destroy the line in a year.

How Long Can an RG6 Run Be Before Signal Drops?

Distance matters, and the rule of thumb is simpler than you might think. For a standard home run — from the outside cable box to a modem in the living room — you are almost always under 100 feet, and signal loss at that length is negligible per the Reddit IT community’s field experience. The Remee guide says RG6 can technically carry a signal over 1,000 feet, but performance degrades noticeably past 300 feet. For any run approaching or exceeding that, step up to RG11, which has lower attenuation and handles longer distances without a signal refresh.

A signal refresh (an amplifier) is needed after roughly 500 meters (1,640 feet) for coax, while Ethernet refreshes every 100 meters. Most homes never approach this limit.

Installation: What Trips People Up

The cable itself is only half the equation. The connectors and bending kill more signals than the wire ever does.

• Don’t use pre-made endings from a big-box store. Comcast’s own business forum notes that cheap store-bought connectors are a common source of intermittent interference. Have a technician or a savvy electrician crimp custom ends onto a bulk spool. The connection stays tight and the shield stays continuous.
• Respect the bend radius. The Viasat spec sheet gives a minimum bend radius of 5.4 inches when loaded and 2.7 inches unloaded. A sharp 90-degree kink crushes the foam dielectric and permanently damages the impedance, creating a reflection point that kills signal.
• Measure with slack. Measure the straight-line path from the cable box to the modem, then add 10–15% for turns, wall clips, and slack. A taut cable is a broken cable waiting to happen.

Identifying Your Cable: Can You Tell RG6 From RG59?

If you own a spool or a pre-made cable and aren’t sure what it is, two quick checks settle it. RG6 is visibly thicker — the jacket diameter is around 0.272 inches versus RG59’s thinner profile. You should also read the jacket printing: “RG6” will be printed along the jacket every foot or two, often followed by “75 Ohm” and a fire rating like “CM” or “CMX.” If you see “RG59” or no designation at all, replace it for any broadband use.

If you’re ready to buy the right cable, check out our tested recommendations for the best coaxial cable for internet.

Fire Safety and Code Compliance

Coaxial cable is regulated for fire safety just like electrical wire. The jacket must carry a CM or CMX fire rating for general home use. In air-handling spaces — above drop ceilings, inside HVAC ducts — plenum-rated coax is required by building codes because standard PVC jackets emit toxic smoke when burned. A plenum violation can void your insurance and is a clear safety hazard. The Remee guide covers this in detail.

How Does Coax Compare to Fiber Optic?

Coaxial cable handles up to 1 Gbps down and 35 Mbps up on standard residential plans, which covers most US households. Fiber optic cable uses glass instead of copper and can carry symmetrical gigabit speeds with lower latency, but it costs significantly more to install and is not available in all areas. As Tailwind Voice & Data notes, coax remains a cost-effective option for homes where shared bandwidth congestion is acceptable and fiber isn’t on the street yet.

Quick Reference: RG6 Specs at a Glance