Theory Of Operation - Humminbird LCR 4x6 Operation Manual

Before attempting to install or operate your Humminbird LCR it is recommended that you read the
operations manual thoroughly. The LCR has a number of special features not found on any other
depth sounder. Therefore, to completely understand all the features we suggest you follow the
instructions in this manual. If, after reading the instructions, there is something you do not
completely understand about the operation of your unit, we recommend you contact our
Customer Service Department-CALL
Our Customer Service hours are Monday- Friday 8:00 A. M.-5:00 P. M.
Please complete your warranty card and return it to us immediately.
Thank you.
INTRODUCTION
Congratulations on selecting the LCR4x6. Your new Humminbird LCR incorporates the most
advanced, innovative concepts in sonar equipment. The LCR is probably the most intelligent
depth sounder ever created. Advanced microcomputer technology is used to simplify its
operation, not complicate it, so you can quickly learn the basics of operating your unit. You will
find even the advanced features, such as Split Screen Zoom and Screen Memory, are easy to
learn and fun to use.
Your Humminbird LCR has a number of outstanding features including a unique automatic
feature. This computer-controlled feature, pioneered by Humminbird, makes using your LCR as
simple as pushing the "Power" button. The computer will automatically adjust the sensitivity,
change the depth scale even if the bottom goes off the screen and black out everything below the
bottom to make the display easy to read.
The LCR4x6 control panel is another Humminbird innovation. You have complete control of all
the unit's features with just seven buttons and an easy-to-understand display of all adjustments is
right on the screen. You will quickly see that the advanced technology of the LCR4x6 is easy to
use and understand.
Other features include Split Screen Zoom and Bottom Lock, Screen Memory, Total Screen
Update, large digital bottom depth readout, Fish Alarm, Bottom Alarm, and optional Surface
Temperature and Speed Gauges for readings on the LCR screen.
The LCR has a large 6-inch by 4-inch visibility LCD, a night-light, waterproof enclosure, and a
low profile swivel mount. Read this operations manual thoroughly to get the most from all the
LCR's features. You'll have fun learning to use your LCR4x6 and it will give you many hours of
fishing and boating pleasure.

THEORY OF OPERATION

You Humminbird LCR works on the basic principle of sonar. An electronic signal is generated
within the control head of the unit. When coupled to the transducer, this signal is converted to an
ultrasonic signal and is transmitted toward the bottom. The speed of the ultrasonic signal
travelling through the water is approximately 4800 feet per second.
The signal travels through the water until it strikes an object or the bottom. At this instant it is
reflected back, picked up by the transducer, reconverted to an electric signal and is recorded on
the display of the LCR.
The reading at the far right position of the screed shows what is being passed over at that time.
As new information is received, the old information is shifted to the left and the new information is
added. The information is retained until it disappears from the left side of the screen. Figure 1
illustrates a typical display.
One of the unique features of your LCR is the Split Screen Zoom with Total Screen Update.
Figure 1 shows a Split Screen Zoom display with the full depth range information on the right and
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