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Radio waves travel from one point to another by sev-
eral different means. The general term for these meth-
ods of wave travel is "propagation." You may know
that "shortwave" signals can be propagated over dis-
tances of several thousand miles by reflection off of
the upper regions of the atmosphere.
Your hand-held transceiver, on the other hand, oper-
ates on the so-called VHF (Very-High Frequency) band.
On this band, radio waves usually do not reflect 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 dis-
tance when using your radio. If you operate from in-
side a car or building, any metal around you can absorb
much of the signal, both transmitted and received. Cov-
erage may therefore be very poor under those condi-
tions. However, if you must operate from indoors, mov-
ing 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.
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U
R
NDERSTANDING
W
ADIO
AVES
On final note regarding propagation is useful in im-
proving coverage. Because radio waves at VHF is
similar to light waves, they do reflect, to varying de-
grees, off of hills, buildings, and the like. In a crowded
urban area, with many close buildings close together,
many reflections may occur, and interfere with one
another, causing variations in signal strength at dif-
ferent locations.
Therefore, if a signal is weak and you walk a few
feet in any direction, reception may suddenly become
clear, because a particular reflection path may be-
come dominant. Reflections are frequently useful,
as they can allow for communications between two
stations over a highly obstructed path.
VX-900 O
M
PERATING
ANUAL
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