General Class Presentation Notes

• Moonbounce
  distance can be unlimited; both must be able to "see" the moon
  Least path loss when moon is at perigee
  Very wide bandwidth RX is needed!
  144MHz has 2 minute sequences
  432MHz has 2.5 minute sequences
  Stations can be found 144.0-144.1, 432.0-432.1 (bottom .1 for both).
• Libration fading
  fluttery, irregular signal
• Meteor Stuff
  Cylindrical region of free electrons at the E layer forms during a meteor strike
  Meteor-scatter can be found from 28-148MHz
  144MHz has 15-second sequences
• Transequatorial Propagation
  Between two points the same distance north and south of the Equator
  Around 5,000 mile-range
  Best in afternoon or early evening
• Longpath Propagation
  Stations sound strongest off the back of the beam
  Can be found 10 thru 160m
  Most frequently on 20m
• Multi-path Propagation
  Produced echo on the signal of another station
  Usually distant
  Creates phase differences which cause selective fading
• Gray-Line
  Radio signals travel along the line between day and night
  Usually at sunrise and sunset
  Caused by decreased solar absorption, without a change in the MUF
  Contacts usually around 8,000 to 10,000 miles
• Auroral Propagation
  Causes fluttery tone on CW signals
  Caused by the sun releasing charged particles
  Occurs at E-region height
  Best with CW
  Point the beam north to take advantage of
• Horizon/Ground
  VHF/UHF radio horizon 15% more than the geometric horizon since radiowaves can bend
  Main lobe takeoff angle of a 3ele horizontal beam decreases with height
  Main lobe takeoff angle of a horizontally polarized antenna on a hill decreases in the downhill direction (obviously)
  Ground wave propagation distances decrease as frequency decreases
  Ground wave usually polarized vertically
• The paths themselves
  A ray that travels great distances in the F2 region (horizontally) is a Pedersen Ray
  Tropospheric Ducting causes VHF propagation over 500 miles

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