in gain from 1 to 2 is very small as compared to the change in
gain from 5 to 6, i.e. gain at 1 to 2 is for 50 to 100 ft. while gain
at 5 to 6 is for
1
⁄2 mile to 2 miles. This is not an exact measure,
the ranges will be different depending on all of the factors
involved. NOTE - If the signal is not line-of-sight, distance esti-
mation is not reliable.
ADVANCED TOPICS AND SPECIAL SITUATIONS
Obstacles
Think about what happens to the signal strength of your favorite
radio station when your vehicle enters a tunnel. Generally the
signal becomes very faint or you lose it altogether. The same
effect can be experienced when searching for a cell phone signal
in a deep canyon. Radio waves at certain frequencies have great
difficulty penetrating rock and other solid objects. Therefore, it is
generally more challenging to locate an object in rugged terrain
rather than on a flat plain.
Signal Bounce
The term that professionals use to describe the behavior of radio
waves deflecting and reflecting off objects is “signal bounce.”
Many different types of substances reflect radio waves including
rock (particularly shear cliffs), water and wet vegetation. “Bounce”
has a tendency to complicate radio-location, as the signal will be
affected by the composition and shape of the reflecting object.
This phenomenon has the potential to create strong signals in sev-
eral discrete directions. Signal Bounce should not be intimidating -
we just need to learn how to manage it.
Polarization
The signal will be strongest when the orientation of the receiver
antenna matches the orientation of the transmitting antenna. For
example, if the transmitting antenna is perpendicular to the
ground, the signal strength detected by the receiver will be great-
est when the antennas are positioned vertically. You can test this
for yourself by activating a transmitter and orienting the antenna
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