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SESK: Stuff Everyone Should Know · sesk.info/ham-cw-narrowest

Which of these signal types has the narrowest bandwidth?

CW, Morse code.

  1. CW ✔
  2. SSB voice
  3. FM voice

Why: CW is just a carrier switched on and off, so it takes very little room. Voice modes like SSB and FM need much wider bandwidth.

Huh, didn't know that: A CW signal needs only about 150 Hz of bandwidth.

The dad joke
Why did the CW signal fit in the tiny parking spot? It's the narrowest mode on the band.
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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

Ham RadioWhat is the approximate bandwidth of a typical single sideband voice signal?Ham RadioWhat is the approximate bandwidth of an FM voice signal on VHF repeaters?Ham RadioWhich voice mode is often used for long-distance, weak signal contacts on VHF and UHF?

That's stuff everyone should know.