16
VX-520U O
PERATING
M
ANUAL
U
NDERSTANDING
R
ADIO
W
AVES
Radio waves travel from one point to another by several different means. The
general term for these methods of wave travel is “propagation”. You may
know that “shortwave” signals can be propagated over distances of several
thousand miles by reflection off of the upper regions of the atmosphere.
Your hand-held transceiver, on the other hand, operates on the so-called UHF
(Ultra-High Frequency) band. On this band, radio waves usually do not re-
flect off of the atmosphere. Instead, the radio waves behave almost as light:
they travel in a straight line, and when they meet a building or obstruction,
they go no further in that direction.
Therefore, it is important that you be as high and free from obstructions as
possible to cover the greatest distance when using your radio. If you operate
from inside a car or building, any metal around you can absorb much of the
signal, both transmitted and received. Coverage may therefore be very poor
under those conditions. However, if you must operate from indoors, moving
next to a window will improve communications.
In view of the factors just discussed, you can easily see the potential benefit
of holding the radio up high near your mouth while transmitting. In this way
the antenna is high and clear, and coverage is best.
On final note regarding propagation is useful in improving coverage. Be-
cause radio waves at UHF are similar to light waves, they do reflect, to vary-
ing degrees, off of hills, buildings, and the like. In a crowded urban area, with
many close buildings close together, many reflections may occur, and inter-
fere with one another, causing variations in signal strength at different loca-
tions.
Therefore, if a signal is weak and you walk a few feet in any direction, recep-
tion may suddenly become
clear, because a particular
reflection path may be-
come dominant. Reflec-
tions are frequently useful,
as they can allow for com-
munications between two
stations over a highly ob-
structed path.
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