Humminbird 405SX Fish Finder User Manual


 
USING THE 405SX
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 600'
and back again in less than
¹⁄₄ of a second. It is unlikely that your boat can
"outrun" this sonar signal.
The
405SX is a 200 kHz, single-beam fishfinder. The 200 kHz frequency
provides excellent sonar resolution (the ability to distinguish small returns or
returns which are close to the bottom), while providing depth capabilities to
600. The shape of the sonar beam is symmetrical and covers an area of
approximately 24 degrees side to side and front to rear.
Actual depth capability depends on factors such as bottom hardness, water
conditions, and transducer installation. Units will typically read to deeper
depths in fresh water than in salt water.
SIMULATOR OPERATION
The 405SX contains a simulator that allows you to use the unit as if you are on the
water. The simulator is invaluable for learning how to operate the
405SX.
There are two ways to start the simulator. If the unit is powered off, press and hold
the POWER button for approximately three seconds until you hear a continuous chirp.
The simulator can also be started by selecting the Simulator option on the start-
up screen after you power-up the unit. When this screen is shown, simply press