What is the most common impedance of coaxial cables used in amateur radio?

The most common impedance of coaxial cables used in amateur radio is 50 ohms. This impedance is favored primarily for its balance between power handling capability and low loss characteristics, making it ideal for radio frequency (RF) applications. Coaxial cables with 50-ohm impedance provide an effective match for most amateur radio transmitters and receivers, enabling efficient power transfer and minimizing reflection losses during operation.

In addition to its practical applications, many antennas used in HF (high frequency) and VHF (very high frequency) bands are designed to work efficiently with 50-ohm coaxial cables, establishing a standard that is widely adopted in the amateur radio community. The design of the coaxial cable, featuring the central conductor and the outer shield, helps maintain this impedance, making it a reliable choice for many operators.

While other impedances like 75 ohms are more commonly used in television and video applications, and 600 ohms has traditional uses in audio and telecommunication wiring, they do not meet the specific needs of amateur radio as effectively as 50 ohms does. Therefore, knowing that 50-ohm coaxial cables are the most commonly used in amateur radio is crucial for anyone starting in the hobby.