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SESK: Stuff Everyone Should Know · sesk.info/hame-sporadic-e

What is sporadic E?

Patches of dense ionization in the E region that come and go.

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  1. A steady daily layer above the F layer
  2. A sudden radio blackout on the sunlit side
  3. Transient, localized patches of high electron density in the E region ✔

Why: NOAA's glossary describes sporadic E as transient, localized patches of relatively high electron density in the E region of the ionosphere. The patches come and go with little warning.

Huh, didn't know that: Sporadic E is most likely between sunrise and sunset.

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Been there, sun that.
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References

Answer: Transient, localized patches of high electron density in the E region. NOAA's glossary describes sporadic E as transient, localized patches of relatively high electron density in the E region of the ionosphere. The patches come and go with little warning.

  1. NOAA SWPC Space Weather Glossary www.spaceweather.gov/content/space-weather-glossary
    Transient, localized patches of relatively high electron density
    Checked 2026-10-11.
  2. NCVEC 2024-2028 Amateur Extra Class Question Pool www.ncvec.org/downloads/2024-2028%20Extra%20Class%20Question%20Pool%20and%20Syllabus%20Public%20Release%20with%204th%20Errata%20Feb%204%202026.pdf
    D. Between sunrise and sunset
    Checked 2026-10-11.
  3. NCVEC 2024-2028 Amateur Extra Class Question Pool www.ncvec.org/downloads/2024-2028%20Extra%20Class%20Question%20Pool%20and%20Syllabus%20Public%20Release%20with%204th%20Errata%20Feb%204%202026.pdf
    A. Around the solstices, especially the summer solstice
    Checked 2026-10-11.

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