How Sonar Works - Humminbird 500 SERIES 580 Operation Manual

How Sonar Works

Sonar technology is based on sound waves. The 500 Series™ Fishfinder uses
sonar to locate and define structure, bottom contour and composition, as
well as depth directly below the transducer.
Your 500 Series™ Fishfinder 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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