Layer Properties

  • D layer at 70-80 km is weakly ionised but during the day, particularly in summer, can absorb frequencies below 3-4 MHz, preventing Dx at these frequencies.  The layer disappears at night
  • E Layer at same altitude day and night (120 km).  Intensity increases with sunlight, max at noon
  • F Layer separates during daylight into F1 and F2 layers
  • F Layer (night-time) height is 350 km
  • F1 (day-time) height is 200 km and F2 (day-time) is 450 km