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The Great Circle Chart of the world. The map is centered on
Christmas Island. Other maps can be obtained which are centered
on other cities and Locator including your QTH locator.
Basically the map provides a visual image so you can place
yourself in relation to whatever country you are in contact with.
Because radio waves tend to reflect specularly when they do
reflect, they would continue (if not absorbed by the earth)
around the globe back to the point of origin and on again. The
numerous reflections compose a great circle path. Around a
circle whose center is the earth’s center. The direction they
travel would therefore depend on the antenna orientation.
Short Path means that the distance between the two stations is
the shortest distance along a great arc. If the signal were to
continue reflecting from earth to ionosphere and back again, if
the contact would be via long path means that you are using the
longest rather . This is because propagation conditions on the
long path are far superior to short path propagation. Except for
a north-south path along the border between day and night, long
path openings involve both day and night time propagation.
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