How Your Sonar Works - Lowrance LCX-112C Operation Instructions Manual

NOTICE!
The storage and operation temperature range for your unit is from -
20 degrees to +167 degrees Fahrenheit (-28 degrees to +75 degrees
Celsius). Extended storage or operation in temperatures higher or
lower than specified will damage the liquid crystal display in your
unit. This type of damage is not covered by the warranty. For more
information, contact the factory's Customer Service Department;
phone numbers are listed on the last page of the manual.

How Your Sonar Works

Sonar has been around since the 1940s, so if you already know how it
works, skip down to read about the relatively new technology of GPS.
But, if you've never owned a sonar fish finder, this segment will tell you
the underwater basics.
Sonar is an abbreviation for SOund NAvigation and Ranging, a technology
developed during World War II for tracking enemy submarines. (Lowrance
developed the world's first transistorized sportfishing sonar in 1957.) A
sonar consists of a transmitter, transducer, receiver and display. Here's a
simple explanation of how it finds the bottom and the fish.
The transmitter emits an electrical impulse, which the transducer
converts into a sound wave and sends into the water. (Humans or fish
can't hear the sound frequency.) The sound wave strikes an object (fish,
structure or bottom) and bounces back to the transducer, which
converts the sound back into an electrical signal.
The receiver amplifies this return signal, or echo, and sends it to the
display, where an image of the object appears on the scrolling sonar
chart. The sonar's microprocessor calculates the time lapse between the
transmitted signal and echo return to determine the distance to the
object. The whole process repeats itself several times each second.
Your sonar unit can record a log of the sonar signals that scroll across
the screen and save them to the MMC memory card. (These recordings
are also called sonar charts or sonar graphs.) You can replay this sonar
log in the unit using the Sonar Simulator function, or play it back on a
personal computer using our free Sonar Viewer. The viewer is available
for download from the Lowrance web site, www.lowrance.com.
You can save several different sonar log files, erase them and record
new ones, over and over again. The size of your sonar recordings are
only limited by the free space available on your MMC.
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