Question
What is the most common impedance of coaxial cables used in amateur radio?
Answer Options
- A) 8 ohms
- B) 50 ohms
- C) 600 ohms
- D) 12 ohms
Correct Answer: B
Explanation
The characteristic impedance of a transmission line is its inherent opposition to the flow of AC power (T5C05), which is determined by the physical geometry of the cable (conductor size and spacing).
For nearly all amateur radio RF applications—including all HF, VHF, and UHF antenna feed lines—the international standard characteristic impedance is 50 ohms. Radio transceivers, amplifiers, and most antennas are all designed to operate into and out of a 50\text{ Ohm} impedance to ensure maximum power transfer and low SWR.
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