HamSandwich

Yes, you still need a callsign.

Study › Amateur Extra › E3B › E3B09

E3B09

RADIO WAVE PROPAGATION · Transequatorial propagation; long-path propagation; ordinary and extraordinary waves; chordal hop; sporadic-E mechanisms; ground-wave propagation

E3B09E3B →

At what time of year is sporadic-E propagation most likely to occur?

  1. AAround the solstices, especially the summer solstice
  2. BAround the solstices, especially the winter solstice
  3. CAround the equinoxes, especially the spring equinox
  4. DAround the equinoxes, especially the fall equinox
Why Sporadic-E clouds of intensely ionized patches in the E layer (about 60-70 miles up) form most often in a broad season centered on the summer solstice, with a weaker secondary peak near the winter solstice. In the northern hemisphere that means a strong May-through-August season for 10, 6 and sometimes 2 meters. The mechanism is tied to wind shear and meteoric ionization rather than to solar flux, so Es appears even at sunspot minimum.
Watch out The equinox answers describe the pattern for F2-layer DX and transequatorial propagation, which favor spring and fall, not Es. The winter-solstice choice names the real but much weaker secondary Es peak.
Sporadic-E = summer sizzle: the big 6 meter season peaks around the June solstice.
HamSandwich explanation, first draft. The question and answers are the NCVEC text.
← E3B08 All of E3B E3B10 →

The rest of E3B

  1. E3B01 Where is transequatorial propagation (TEP) most likely to occur?
  2. E3B02 What is the approximate maximum range for signals using transequatorial propagation?
  3. E3B03 At what time of day is transequatorial propagation most likely to occur?
  4. E3B04 What are "extraordinary" and "ordinary" waves?
  5. E3B05 Which of the following paths is most likely to support long-distance propagation on 160 meters?
  6. E3B06 On which of the following amateur bands is long-path propagation most frequent?
  7. E3B07 What effect does lowering a signal's transmitted elevation angle have on ionospheric HF skip propagation?
  8. E3B08 How does the maximum range of ground-wave propagation change when the signal frequency is increased?
  9. E3B09 At what time of year is sporadic-E propagation most likely to occur?
  10. E3B10 What is the effect of chordal-hop propagation?
  11. E3B11 At what time of day is sporadic-E propagation most likely to occur?
  12. E3B12 What is chordal-hop propagation?
  13. E3B13 What type of polarization is supported by ground-wave propagation?
Powerwerx SS-30DV 30A DC Power SupplySponsored · View on Amazon →Diamond X50A Dual Band Base AntennaSponsored · View on Amazon →