Coaxial cable carries radio frequency (RF) signals for video, data, and communications by isolating a center conductor inside a dielectric insulator, a metallic shield, and an outer jacket. Choosing the right coax type depends on your application — CCTV, cable TV, broadband internet, ham radio, or commercial wireless — and the distance, frequency, and signal loss your installation can tolerate. This guide breaks down every major coax type so you can specify the right cable the first time.
How Coaxial Cable Works
Every coaxial cable shares the same four-layer construction. A solid or stranded center conductor (usually copper or copper-clad steel) carries the signal. A dielectric insulator — typically foam or solid polyethylene — maintains the precise spacing between the center conductor and the shield that determines the cable's characteristic impedance. A metallic shield (braided copper, aluminum foil, or both) blocks electromagnetic interference (EMI) and keeps the signal contained. Finally, an outer jacket (PVC, PE, or plenum-rated compounds) protects the assembly from physical damage, moisture, and UV exposure.
The "RG" designation originated in the U.S. military's coaxial cable classification system (MIL-C-17). While the military specifications have largely been replaced and the RG number no longer guarantees specific electrical performance, the RG numbering convention remains the industry shorthand for identifying general coax cable types. The LMR series is a modern product line engineered by Times Microwave Systems as a high-performance replacement for legacy RG cables.
75-Ohm Coaxial Cable: RG59, RG6, and RG11
Cables with 75-ohm characteristic impedance are optimized for video and broadband signal transmission. The 75-ohm impedance minimizes signal loss in video applications and matches the input impedance of televisions, cable modems, and most CCTV equipment. These are the cables you'll find in virtually every residential and commercial video/data installation.
RG59 — Analog Video and Short-Run CCTV
RG59 is the thinnest and most flexible of the 75-ohm video coax cables. It uses a 20 AWG solid copper center conductor with a single braided copper shield (typically 95% coverage) over a solid polyethylene dielectric. The overall diameter is approximately 0.242 inches (6.1 mm).
RG59 was the standard cable for analog CCTV and cable television for decades. It handles frequencies up to about 1 GHz but experiences increasing attenuation at higher frequencies, which limits its usefulness for modern broadband, satellite, and HD video formats compared to RG6. Practical maximum run length for analog video is around 750 feet; for HD-over-coax formats (HD-TVI, HD-CVI), keep runs under 300–500 feet depending on resolution.
Best applications: analog CCTV camera runs under 500 feet, legacy cable TV installations, short baseband video connections, and CCTV systems being upgraded on a budget where existing conduit limits cable diameter.
RG6 — The Modern Standard for Video and Broadband
RG6 has replaced RG59 as the go-to coaxial cable for virtually all residential and commercial video, satellite, and broadband installations. It uses an 18 AWG center conductor (solid copper or copper-clad steel, depending on the application) with dual-layer shielding — an aluminum foil wrap plus a braided aluminum or copper shield. The overall diameter is approximately 0.274 inches (6.9 mm).
The larger center conductor and improved shielding give RG6 significantly lower signal loss than RG59, especially above 100 MHz. RG6 comfortably handles frequencies up to 3 GHz, making it suitable for satellite TV (950–2150 MHz), digital cable, HD-over-coax CCTV, and cable internet (DOCSIS). Maximum recommended run length is 750–1,000 feet for HD video. Satellite runs typically range from 100–200 feet without amplification, though some installations extend to 300 feet depending on LNB output and receiver sensitivity.
RG6 is available in several shielding configurations. Standard dual-shield RG6 works for most residential installations. Quad-shield RG6 adds two more shielding layers (four total) for environments with heavy EMI — near commercial broadcast towers, electrical substations, or industrial equipment. For installations that run through CATV distribution systems or plenum airspaces, specify plenum-rated (CMP) RG6.
Best applications: cable TV, satellite TV, broadband internet (DOCSIS), HD-over-coax CCTV, and any 75-ohm installation under 1,000 feet.
RG11 — Long-Distance, Low-Loss Video Runs
RG11 is the heavy-duty 75-ohm cable built for long runs where RG6 would lose too much signal. It uses a 14 AWG center conductor — solid copper or copper-clad steel (CCS) depending on the application — significantly larger than RG6's 18 AWG, with a foam polyethylene dielectric and dual or quad shielding. The overall diameter is approximately 0.412 inches (10.5 mm).
The larger conductor and dielectric reduce attenuation by roughly 40% compared to RG6 at the same frequency. RG11 can maintain acceptable signal quality on runs exceeding 1,000 feet for analog video and 500+ feet for satellite signals. However, the trade-off is reduced flexibility — the 0.412-inch diameter and stiffer construction make RG11 difficult to route through tight spaces and harder to terminate.
RG11 is most commonly used as trunk cable in CATV distribution systems, long outdoor runs between buildings, and any installation where distance makes RG6 impractical. It is available in direct burial, messenger (aerial), and plenum-rated configurations.
Best applications: CATV trunk lines, long-distance CCTV runs over 1,000 feet, campus-wide video distribution, and outdoor building-to-building connections.
75-Ohm Coaxial Cable Comparison
| Specification | RG59 | RG6 | RG11 |
|---|---|---|---|
| Impedance | 75 Ω | 75 Ω | 75 Ω |
| Center Conductor | 20 AWG solid copper | 18 AWG solid copper or CCS | 14 AWG solid copper or CCS |
| Overall Diameter | ~0.242 in (6.1 mm) | ~0.274 in (6.9 mm) | ~0.412 in (10.5 mm) |
| Shield Type | Single braid (95%) | Foil + braid (dual or quad) | Foil + braid (dual or quad) |
| Attenuation @ 100 MHz | ~3.4 dB/100 ft | ~2.0 dB/100 ft | ~1.5 dB/100 ft |
| Attenuation @ 1 GHz | ~12.0 dB/100 ft | ~6.1 dB/100 ft | ~5.6 dB/100 ft |
| Max Frequency | ~1 GHz | ~3 GHz | ~3 GHz |
| Practical Max Run (video) | ~500–750 ft | ~750–1,000 ft | ~1,000–1,500 ft |
| Flexibility | Most flexible | Moderate | Least flexible |
| Common Connectors | BNC, F-type | F-type, BNC | F-type |
| Typical Applications | Analog CCTV, legacy CATV | Cable TV, satellite, internet, HD CCTV | CATV trunk, long outdoor runs |
50-Ohm Coaxial Cable: RG8 and LMR Series
Cables with 50-ohm characteristic impedance are designed for two-way radio, wireless infrastructure, and RF transmission where power handling and low loss matter more than video signal fidelity. The 50-ohm impedance represents the best compromise between power handling capacity and signal attenuation for RF transmitters and receivers.
RG8 — Ham Radio and High-Power RF
RG8 (also designated RG8/U) is the workhorse 50-ohm coaxial cable for amateur radio and antenna installations. It uses a solid or stranded copper center conductor (typically 10–12 AWG) with a foam or solid polyethylene dielectric and a braided copper shield. The overall diameter is approximately 0.405 inches (10.3 mm).
RG8 handles higher RF power levels than thinner 50-ohm cables and provides reasonable attenuation characteristics for HF and VHF frequencies. It's a practical choice for permanent base station antenna feedlines where runs are under 100 feet. Above 100 feet or at UHF frequencies, signal loss becomes a concern and LMR-400 is the better option.
A popular variant, RG8X (also called "mini-8"), uses a smaller 16 AWG center conductor in a 0.242-inch diameter package. RG8X offers much better flexibility than full-size RG8 at the cost of higher attenuation — it's commonly used for portable or temporary antenna connections, jumper cables, and mobile radio installations where easy routing matters more than minimal loss.
Best applications: ham radio base station feedlines (HF/VHF), marine radio, CB radio, and legacy two-way radio systems.
LMR Series — Modern Low-Loss RF Cable
The LMR (Land Mobile Radio) series, manufactured by Times Microwave Systems, was engineered as a direct upgrade to legacy RG cables. LMR cables use a foam polyethylene dielectric and a bonded aluminum-tape shield with a tinned copper braid overlay, delivering significantly lower attenuation than their RG counterparts while maintaining excellent flexibility.
LMR-200
LMR-200 replaces RG-58 with 40–50% less signal loss in a similar 0.195-inch diameter package. It features a solid bare copper center conductor, foil plus braid shielding (90 dB isolation), and handles frequencies up to 5.8 GHz. LMR-200 is the go-to cable for short antenna jumpers, pigtails, Wi-Fi access point connections, and any application where a thin, flexible cable is needed without sacrificing too much performance.
LMR-240
LMR-240 replaces RG-8X with 35–64% less signal loss, depending on frequency. The 0.240-inch diameter makes it a good middle ground between the portability of LMR-200 and the lower loss of LMR-400. Use LMR-240 for moderate-length antenna runs (up to 50 feet), mobile radio installations, and GPS antenna cables.
LMR-400
LMR-400 is the most widely used cable in the LMR series and a direct replacement for RG-8 and RG-213. At 0.405 inches in diameter, it matches RG-8's size but delivers the lowest loss of any flexible cable in its class — approximately 2.7 dB per 100 feet at 450 MHz versus 4.5 dB for RG-8. The foam dielectric and bonded tape shield also make LMR-400 more flexible and easier to route than standard RG-8.
LMR-400 handles frequencies up to 6 GHz and is available in outdoor-rated (PE jacket), riser-rated (CMR), plenum-rated (CMP), and direct burial configurations. It is the standard feedline cable for commercial wireless, cellular site infrastructure, Wi-Fi backbone runs, and serious amateur radio installations. Ramcorp stocks LMR-400 and other antenna cables in multiple jacket types and put-up lengths.
LMR-600
LMR-600 is the heavyweight of the series, with a 0.590-inch diameter and the lowest attenuation of any flexible coaxial cable in common use. It was not designed as a replacement for any specific RG cable — instead, it fills the gap between flexible coax and rigid hardline for long-distance, high-power RF applications. Use LMR-600 for antenna feedlines exceeding 75 feet, high-power satellite uplinks, commercial wireless infrastructure, and any run where every fraction of a dB matters.
50-Ohm Coaxial Cable Comparison
| Specification | RG8X | RG8/U | LMR-200 | LMR-400 | LMR-600 |
|---|---|---|---|---|---|
| Impedance | 50 Ω | 50 Ω | 50 Ω | 50 Ω | 50 Ω |
| Overall Diameter | ~0.242 in | ~0.405 in | ~0.195 in | ~0.405 in | ~0.590 in |
| Attenuation @ 150 MHz | ~3.6 dB/100 ft | ~1.6 dB/100 ft | ~3.9 dB/100 ft | ~1.5 dB/100 ft | ~0.9 dB/100 ft |
| Attenuation @ 450 MHz | ~6.0 dB/100 ft | ~2.9 dB/100 ft | ~6.8 dB/100 ft | ~2.7 dB/100 ft | ~1.7 dB/100 ft |
| Attenuation @ 1 GHz | ~9.2 dB/100 ft | ~4.5 dB/100 ft | ~10.5 dB/100 ft | ~4.1 dB/100 ft | ~2.5 dB/100 ft |
| Max Frequency | ~1 GHz | ~1 GHz | ~5.8 GHz | ~6 GHz | ~6 GHz |
| Shield Isolation | ~80 dB | ~80 dB | ~90 dB | >90 dB | >90 dB |
| Flexibility | Very flexible | Moderate | Very flexible | Flexible | Less flexible |
| Replaces | — | — | RG-58 | RG-8 / RG-213 | — |
| Typical Applications | Portable/mobile radio, jumpers | Ham radio base stations | Wi-Fi, GPS, short antenna runs | Commercial wireless, ham radio, cellular | Long runs, high-power RF, satellite |
Coaxial Cable Attenuation Chart
Signal attenuation (loss) increases with frequency and cable length. The table below compares attenuation per 100 feet across all major coax types at common operating frequencies. Lower numbers mean less signal loss.
| Cable | Impedance | 100 MHz | 500 MHz | 1 GHz | 2 GHz |
|---|---|---|---|---|---|
| RG59 | 75 Ω | 3.4 dB | 8.1 dB | 12.0 dB | 17.5 dB |
| RG6 | 75 Ω | 2.0 dB | 4.6 dB | 6.1 dB | 8.9 dB |
| RG11 | 75 Ω | 1.5 dB | 3.5 dB | 5.6 dB | 7.2 dB |
| RG8X | 50 Ω | 2.5 dB | 6.2 dB | 9.2 dB | 13.5 dB |
| RG8/U | 50 Ω | 1.2 dB | 3.1 dB | 4.5 dB | 7.0 dB |
| LMR-200 | 50 Ω | 2.7 dB | 7.0 dB | 10.5 dB | 15.4 dB |
| LMR-400 | 50 Ω | 1.0 dB | 2.4 dB | 4.1 dB | 5.3 dB |
| LMR-600 | 50 Ω | 0.6 dB | 1.5 dB | 2.5 dB | 3.4 dB |
Values are approximate and vary by manufacturer. All figures are in dB per 100 feet at 25°C (77°F). Actual performance may differ based on connector quality, installation conditions, and cable age. Always consult the manufacturer's datasheet for certified specifications.
75-Ohm vs. 50-Ohm: Which Do You Need?
The impedance rating is not interchangeable. Using the wrong impedance creates an impedance mismatch that reflects signal energy back toward the source, causing signal loss, interference, and potential damage to transmitters.
| Application | Impedance | Recommended Cable |
|---|---|---|
| Cable TV (CATV) | 75 Ω | RG6 (standard), RG11 (trunk) |
| Satellite TV | 75 Ω | RG6 (quad-shield preferred) |
| Broadband Internet (DOCSIS) | 75 Ω | RG6 |
| CCTV / Security Cameras | 75 Ω | RG59 (analog), RG6 (HD-over-coax) |
| Ham Radio (HF/VHF/UHF) | 50 Ω | LMR-400, RG8 |
| Commercial Two-Way Radio | 50 Ω | LMR-400, LMR-240 |
| Wi-Fi / Wireless Access Points | 50 Ω | LMR-200, LMR-400 |
| Cellular / DAS Infrastructure | 50 Ω | LMR-400, LMR-600 |
| GPS Antenna | 50 Ω | LMR-200, LMR-240 |
As a rule of thumb: if you're connecting video or TV equipment, you need 75-ohm cable. If you're connecting an antenna, radio, or wireless transmitter, you need 50-ohm cable.
Shielding Types and When They Matter
Coaxial cable shielding blocks external electromagnetic interference from corrupting the signal and prevents the cable from radiating its own signal outward. The level of shielding you need depends on the RF environment around the cable run.
Single braid (60–95% coverage) is the simplest shield — a woven mesh of copper or aluminum wire. It provides adequate protection for most residential installations and short commercial runs in low-EMI environments. RG59 typically uses a single braid.
Dual shield (foil + braid) wraps a continuous aluminum foil tape around the dielectric before adding a braided overlay. The foil provides 100% coverage against high-frequency interference while the braid adds low-frequency protection and mechanical strength. Standard RG6 and RG11 use dual shielding. LMR cables use a bonded aluminum tape plus braid for superior isolation.
Quad shield (foil + braid + foil + braid) doubles the dual-shield configuration for maximum EMI rejection. Quad-shield cable is specified for installations near broadcast towers, industrial plants, power lines, or any location where strong RF sources could interfere with the signal. It costs slightly more per foot than dual-shield and is slightly less flexible, but the additional protection is worth it in challenging environments.
For CCTV and CATV installations in commercial buildings, dual-shield is the minimum standard. In industrial or high-EMI environments, always specify quad-shield. For CCTV camera installations, solid copper center conductors are preferred over copper-clad steel (CCS) because some HD-over-coax systems also carry power or control signals over the coax, making solid copper essential for reliable DC current flow.
Jacket Ratings: Plenum, Riser, and Direct Burial
Like all building cable, coaxial cable must carry the appropriate fire rating for the space where it's installed. These ratings are governed by the NEC® and tested to UL® standards.
| Rating | Jacket Code | Required For | Can Also Be Used In |
|---|---|---|---|
| Plenum | CMP | Air-handling spaces (above drop ceilings, under raised floors with HVAC airflow) | Riser, general purpose |
| Riser | CMR | Vertical shafts between floors | General purpose |
| General Purpose | CM / CMG | Horizontal runs within a single floor | — |
| Outdoor / Direct Burial | PE jacket (no fire rating) | Outdoor, underground, aerial | Not for indoor use without transition to rated cable |
You can always use a higher-rated cable in a lower-rated space — CMP coax is code-compliant everywhere. But you cannot use outdoor PE-jacketed coax inside a building without transitioning to rated cable within 50 feet of the penetration point. For more on fire ratings, see our Plenum vs. Riser Cable guide.
Quick Selection Guide
- Identify the impedance — Video/TV/broadband = 75 Ω. Radio/wireless/antenna = 50 Ω.
- Measure the run length — Under 500 ft and 75 Ω? RG6. Over 1,000 ft? RG11. Under 50 ft and 50 Ω? LMR-200 or LMR-240. Over 50 ft and 50 Ω? LMR-400. Over 75 ft and high power? LMR-600.
- Assess the EMI environment — Residential/low-noise = dual shield. Commercial/industrial/high-noise = quad shield.
- Check the fire rating — Plenum space = CMP. Riser = CMR. Outdoor = PE jacket. When in doubt, specify CMP.
- Choose the center conductor — For CCTV with power-over-coax, always use solid copper. For CATV and satellite, copper-clad steel (CCS) is acceptable and more economical.
Frequently Asked Questions
Can I use RG59 instead of RG6 for cable TV?
RG59 will carry a cable TV signal over short distances, but it's not recommended for modern digital cable or internet service. RG6 has lower attenuation at the frequencies used by digital cable (up to 1 GHz) and broadband internet (DOCSIS), which means fewer signal quality issues, fewer service calls, and better throughput. Cable providers typically require RG6 for new installations.
What's the difference between solid copper and copper-clad steel (CCS) center conductors?
Solid copper conducts electricity throughout the entire conductor cross-section, making it essential for applications that pass DC power or control signals over the coax — like CCTV cameras with power-over-coax or satellite LNBs. Copper-clad steel (CCS) has a thin copper layer over a steel core. At RF frequencies, the signal travels primarily on the conductor surface (skin effect), so CCS performs almost identically to solid copper for pure signal transmission. CCS is less expensive and has higher tensile strength, making it a good choice for long CATV or satellite runs where no DC power travels over the cable.
Can I mix 75-ohm and 50-ohm coaxial cable in the same system?
No. Mixing impedances creates a mismatch at the junction point that reflects signal energy back toward the source. This causes standing waves, increased signal loss, and can damage sensitive transmitters. Every component in the coaxial chain — cable, connectors, splitters, amplifiers — must match the system impedance.
Is LMR-400 worth the extra cost over RG8?
In most cases, yes. LMR-400 delivers approximately 35–40% less signal loss than RG8 at VHF/UHF frequencies in the same 0.405-inch diameter. It's also more flexible due to its foam dielectric and bonded tape shield construction. The performance improvement is most significant on longer runs and at higher frequencies. For a permanent base station antenna feedline, LMR-400 is the standard choice among amateur radio operators and commercial installers.
What connectors do I need for each cable type?
Connector type depends on both the cable and the equipment. RG59, RG6, and RG11 most commonly use F-type connectors for CATV and satellite applications, and BNC connectors for CCTV and professional video. RG8 and LMR-400 typically use N-type or PL-259 (UHF) connectors for radio and antenna connections. LMR-200 and LMR-240 often use SMA or N-type connectors for Wi-Fi and wireless equipment. Always match the connector to both the cable size and the equipment port — connectors are cable-specific and not interchangeable between different RG/LMR sizes.
How far can I run coaxial cable before I need an amplifier?
Maximum usable distance depends on the cable type, frequency, and acceptable signal loss for your application. As a general guideline for 75-ohm video: RG59 starts degrading noticeably above 500 feet, RG6 above 750–1,000 feet, and RG11 above 1,500 feet. For 50-ohm RF: LMR-400 is typically good for 100–200 feet at UHF frequencies, and LMR-600 extends that to 200–500 feet. Beyond these distances, add a line amplifier (for receive systems) or move the transmitter closer to the antenna to reduce feedline loss.
Do I need plenum-rated coax for a drop ceiling installation?
If the space above the drop ceiling is used as an air-handling plenum (part of the HVAC system), then yes — NEC® requires CMP-rated cable. If the drop ceiling is simply a concealed space with no air circulation for HVAC, general-purpose (CM) cable may be acceptable, but check with your local AHJ. When in doubt, use CMP — it's code-compliant everywhere and eliminates the risk of a failed inspection.
Related Resources
- How to Choose the Right Cable for Your Project
- Cat5e vs Cat6 vs Cat6A: Network Cable Selection Guide
- Plenum vs. Riser Cable: CMP, CMR, CL2P & CL3P Ratings Explained
- How to Read a Cable Print Legend: Markings, Codes & What They Mean
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Disclaimer: This guide is provided for informational purposes only and is not installation advice. Installing wire & cable can be dangerous and pose a risk of possible electric shock or other hazards. Specifications, availability, and pricing are subject to change without notice. Always verify product specifications with the manufacturer's current datasheet before ordering. Consult a licensed professional for installation advice. Images are for illustration purposes and may not reflect actual installed products.
The information on this page is provided for general reference only and may contain errors or omissions. NEC® is a registered trademark of the National Fire Protection Association (NFPA®). UL® is a registered trademark of Underwriters Laboratories. LMR® is a registered trademark of Times Microwave Systems. All other trademarks, product names, and brand names referenced on this page are the property of their respective owners. Ramcorp Wire & Cable is not affiliated with or endorsed by these organizations unless explicitly stated.