Insignia 350TX - Manual (Page 8)

USING THE 350TX
HOW SONAR WORKS
6
HOW SONAR WORKS
Your Humminbird unit uses sonar to
locate and define underwater objects,
define the bottom terrain, as well as
determine distance.
Sonar technology is based on sound
waves. Your Humminbird unit sends
out a sound wave signal. With this
signal it determines distance by
measuring the time between the
transmission of the sound wave and
when the sound wave is reflected off
an object. Your Humminbird 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
70m (240') and back again in less than
¹⁄₄ of a second. It is unlikely that
your boat can "outrun" this sonar signal.
The 350TX is a dual frequency, tri-beam unit, and generates three distinct
sonar signals - one narrow, two wide. Each signal is optimized for a
particular purpose. First, the center beam transmits at a frequency of
200 kHz in a 20° (narrow) symmetrical pattern for greater depth capability
and excellent detail. Information from this center beam is used to draw the
graphic representation of the bottom on the display.
The left and right beams are generated at 455 kHz for increased sonar
resolution and are shaped in an elliptical pattern for greater area of
coverage. (45º side to side, and 16º front to back.) Information from these
two beams in conjunction with the center beam is used to accurately
detect the presence and location of fish.
The combination of the three beams and dual frequencies, provides the best
possible combination of a large area of coverage and a high level of detail.