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E3B04

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

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What are "extraordinary" and "ordinary" waves?

  1. AExtraordinary waves exhibit rare long-skip propagation, compared to ordinary waves, which travel shorter distances
  2. BIndependently propagating, elliptically polarized waves created in the ionosphere
  3. CLong-path and short-path waves
  4. DRefracted rays and reflected waves
Why When a radio wave enters the ionized plasma of the ionosphere, the Earth's magnetic field makes the medium birefringent: the wave splits into two components, called the ordinary (o) and extraordinary (x) waves. Each is elliptically polarized and rotates in the opposite sense, and each sees a different refractive index, so they refract, absorb, and travel slightly differently and arrive independently. Their recombination at the receiver with varying phase is one cause of polarization fading. This effect is called magnetoionic splitting.
Watch out The name tempts people into thinking "extraordinary" means an unusual or rare long-skip path, but the term is purely a plasma physics label for one of the two magnetoionic modes, not a description of distance.
Ordinary/extraordinary = one wave split in two by Earth's magnetic field, both elliptically polarized.
HamSandwich explanation, first draft. The question and answers are the NCVEC text.
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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?
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