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How Sonar Works
Sonar technology is based on sound waves. The 300 Series™ Fishing System uses
sonar to locate and define structure, bottom contour and composition, as well as
depth directly below the transducer.
Your 300 Series™ Fishing System sends a sound wave signal and determines distance
by measuring the time between the transmission of the sound wave and when the
sound wave is reflected off of an object; it then uses the reflected signal
to interpret location, size, and composition of an object.
Sonar is very fast. A sound wave can travel from the surface to a depth of 240 ft
(70 m) and back again in less than 1/4 of a second. It is unlikely that your boat can
"outrun" this sonar signal.
SONAR is an acronym for SOund and
NAvigation Ranging. Sonar utilizes precision
sound pulses or "pings" which are emitted
into the water in a teardrop-shaped beam.
The sound pulses "echo" back from objects
in the water such as the bottom, fish and
other submerged objects. The returned
echoes are displayed on the LCD screen.
Each time a new echo is received, the old
echoes are moved across the LCD, creating
a scrolling effect.
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When all the echoes are viewed side by
side, an easy to interpret "graph" of the
bottom, fish and structure appears.
The sound pulses are transmitted at various
frequencies depending on the application.
Very high frequencies (455 kHz) are used for
greatest definition but the operating depth
is limited. High frequencies (200 kHz) are
commonly used on consumer sonar and
provide a good balance between depth. Low
frequencies (83 kHz) are typically used to
achieve greater depth capability.
