General Class Presentation Notes
Mike DeChristopher, K1KAA
These are notes to a presentation I gave for a General license class run by the Hampden County Radio Association sometime in 2006. Feel free to use them for your own instruction, studying, or general
information purposes.
- 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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