SESKStuff Everyone Should Know
SESK: Stuff Everyone Should Know · sesk.info/ham-coax-50-ohms

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

50 ohms.

  1. 600 ohms
  2. 50 ohms ✔
  3. 8 ohms

Why: Most ham radios, antennas and coax are designed for 50 ohms. Matching them keeps SWR low and delivers the most power to the antenna.

Huh, didn't know that: Cable TV coax is usually 75 ohms, a different standard.

The dad joke
Why did the coax refuse to change? It was set in its 50-ohm ways.
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Sources

  1. NCVEC 2026-2030 Technician Question Pool (Feb 19, 2026 release) https://www.ncvec.org/downloads/2026-2030%20Technician%20Pool%20and%20Syllabus%20Public%20Release%20Feb%2019%202026.pdf

Test yourself in the game

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That's stuff everyone should know.