Coaxial Cable Types (RG Series)

Direct Answer

Coaxial cables transmit high-frequency radio frequency (RF) and television signals under MIL-C-17 standards through a concentric center conductor, dielectric insulator, metallic shield, and outer jacket, categorized into 75-Ohm video/broadband series (RG-6, RG-59, RG-11) and 50-Ohm wireless/RF series (RG-58, RG-8X, LMR-400).

Source: MIL-C-17 (Radio Frequency Coaxial Cables) / SCTE Standards / ANSI/TIA-568 · Last reviewed Aug 28, 2026

Specs

Governing Standards	MIL-C-17 / SCTE (Society of Cable Telecom Engineers) / ANSI/TIA-568
RG-6 / RG-6 Quad Shield (75Ω)	Center Conductor: 18 AWG (1.02 mm) \| Outer Dia: 6.86 mm (0.270") \| Satellite TV, Cable DOCSIS 3.1, HDTV Antennas
RG-59 (75Ω Legacy / CCTV)	Center Conductor: 20–22 AWG (0.81 mm) \| Outer Dia: 6.15 mm (0.242") \| Baseband analog CCTV, short-run composite video
RG-11 (75Ω Long-Distance Drop)	Center Conductor: 14 AWG (1.63 mm) \| Outer Dia: 10.3 mm (0.405") \| Heavy low-loss underground long-run drops
RG-58 (50Ω RF / Two-Way Radio)	Center Conductor: 20 AWG (0.90 mm) stranded \| Outer Dia: 4.95 mm \| CB Radio, amateur VHF/UHF, Wi-Fi pigtails
LMR-400 (50Ω Ultra Low-Loss)	Center Conductor: 10 AWG (2.74 mm) solid copper-clad aluminum \| Cellular towers, 2.4/5GHz Wi-Fi antenna masts
Impedance Matching Rule	Never mix 50Ω and 75Ω systems; impedance mismatch causes high Standing Wave Ratio (SWR) and RF reflections

Standard Coaxial Cable Specification & Signal Attenuation Matrix

Coaxial Cable Type	Characteristic Impedance	Center Conductor Gauge	Outer Diameter (mm)	Attenuation at 100 MHz (per 100 ft)	Attenuation at 1000 MHz (1 GHz)	Primary Application
RG-6 (Standard)	75 Ohms (75Ω)	18 AWG Solid (1.02 mm)	6.86 mm (0.27")	2.0 dB	6.1 dB	Modern Cable TV, DOCSIS Internet, Satellite
RG-6 Quad-Shield	75 Ohms (75Ω)	18 AWG Solid	7.50 mm (0.30")	2.0 dB	6.1 dB	High-EMI environments, dense server racks
RG-59	75 Ohms (75Ω)	20 AWG (0.81 mm)	6.15 mm (0.24")	3.4 dB	11.2 dB	Analog composite video, short CCTV runs
RG-11 (Heavy)	75 Ohms (75Ω)	14 AWG Solid (1.63 mm)	10.30 mm (0.40")	1.0 dB	3.8 dB	Underground utility drops (>150 ft runs)
RG-58	50 Ohms (50Ω)	20 AWG Stranded	4.95 mm (0.19")	4.5 dB	16.5 dB	Two-way CB radio, marine VHF, mobile antennas
LMR-400	50 Ohms (50Ω)	10 AWG Solid (2.74 mm)	10.30 mm (0.40")	1.2 dB	4.1 dB	Wireless base stations, Helium/LoRa antennas

Why 75-Ohm (Video) Differs from 50-Ohm (Radio/RF)

75-Ohm (Minimum Signal Attenuation): Mathematically, a coaxial cable achieves its lowest possible signal loss (attenuation) when the ratio of outer-to-inner conductor diameters produces 77 Ohms. Standardized as 75Ω, it is optimal for carrying weak TV/video signals over long distances.
50-Ohm (Maximum Power Handling): A coaxial cable maximizes RF power throughput (voltage breakdown vs current capacity) at 30 to 50 Ohms. Standardized as 50Ω, it is mandatory for radio transmitters and Wi-Fi power transmission.