What is the impedance of the most commonly used coaxial cable in amateur radio?

The most commonly used coaxial cable in amateur radio has an impedance of 50 ohms. This is primarily due to its balance between power handling capability and minimal signal loss at the frequencies typically used by amateur radio operators.

Coaxial cables are designed to carry radio frequency signals effectively, and their impedance is an important characteristic that influences how well they can transmit these signals without reflections that can lead to signal degradation. The 50-ohm impedance is ideal for many applications, including UHF and VHF communications, and provides a good compromise between efficient power transfer and minimal losses.

While there are other impedance values for coaxial cables, such as 75 ohms (commonly used for video applications) and 300 ohms (used for open wire lines), 50 ohms is the standard for amateur radio. The use of 50-ohm coaxial cable ensures compatibility with most transmitters and antennas designed for amateur radio frequencies, facilitating effective communication.