RG6 and RG11 both have a nominal impedance of

RG6 and RG11 both have a nominal impedance of

• A. 50 Ohms
• B. 60 Ohms
• C. 65 Ohms
• D. 75 Ohms

Answer: (D)

The key idea is matching the transmission line to the system that uses it. RG6 and RG11 are both common coaxial cables designed for video and RF distribution, and they are specified as 75-ohm cables. This 75-ohm impedance is chosen because it aligns with the input impedance of most video equipment (tuners, TVs, cable/satellite receivers) and the broadcast networks they connect to, minimizing reflections and signal loss across the wide frequency ranges used for video. Even though RG11 is thicker and has lower attenuation than RG6, they share the same nominal impedance, so they can be used together in a system without impedance mismatches. The alternative 50-ohm standard exists for different RF applications where power handling and different loss characteristics are prioritized, but for consumer video and many CCTV/video distribution applications, 75 ohms is the standard.

The key idea is matching the transmission line to the system that uses it. RG6 and RG11 are both common coaxial cables designed for video and RF distribution, and they are specified as 75-ohm cables. This 75-ohm impedance is chosen because it aligns with the input impedance of most video equipment (tuners, TVs, cable/satellite receivers) and the broadcast networks they connect to, minimizing reflections and signal loss across the wide frequency ranges used for video.

Even though RG11 is thicker and has lower attenuation than RG6, they share the same nominal impedance, so they can be used together in a system without impedance mismatches. The alternative 50-ohm standard exists for different RF applications where power handling and different loss characteristics are prioritized, but for consumer video and many CCTV/video distribution applications, 75 ohms is the standard.