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SESK: Stuff Everyone Should Know · sesk.info/hamg-muf-meaning

What does MUF stand for?

Maximum Usable Frequency between two points.

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  1. Minimum Usable Frequency for communications between two points
  2. Maximum Usable Frequency for communications between two points ✔
  3. Maximum Usable Frequency during a 24-hour period

Why: The MUF is the highest frequency that will be refracted back to Earth for a path between two specific points. It changes with time, season and solar activity.

Huh, didn't know that: The LUF is the Lowest Usable Frequency for communications between two specific points.

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I tried to make a joke about light waves, but it didn't have the right frequency.
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References

Answer: Maximum Usable Frequency for communications between two points. The MUF is the highest frequency that will be refracted back to Earth for a path between two specific points. It changes with time, season and solar activity.

  1. NCVEC 2023-2027 General Class Pool and Syllabus (6th Errata, Feb 4 2026) ncvec.org/downloads/General%20Class%20Pool%20and%20Syllabus%202023-2027%20Public%20Release%20with%206th%20Errata%20Feb%204%202026.pdf
    The Maximum Usable Frequency for communications between two points
    Checked 2026-10-10.

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