Si-tex SNS-1100, User Manual

Page: 69 / 114

User Manual -
69
5. FISH FINDER
SNS 700fe/SNS 700fi
The Fish Finder consists of a high power transmitter, sensitive receiver and a transducer. The
Fish Finder sends an electrical pulse to the transducer which contains an element that converts
the pulse into acoustic (sound) wave which is sent through the water. As this wave travels from
the transducer to the bottom, it may strike fish, structures, thermoclines (temperature changes
in the water). When the wave strikes an object(s) a certain amount of the wave is reflected back
to the transducer depending on the composition and shape of the object. When the reflected
wave is returned to the transducer it is converted into a voltage and is amplified by the receiver,
processed and sent to the display. The speed of sound in water is roughly 4800 ft./sec, so the
time lapse between the transmitted signal and the received echo can be measured and the
distance to the object determined.
Fig. 5 - Fish Finder working principle
5.1 SETTING THE INTERNAL FISH FINDER ON
The internal Fish Finder driver is connected directly to the dedicated serial Port2.
To switch the internal Fish Finder transmission On follow the procedure:
[MENU] + “Advanced Options” + [ENTER] + “Input/Output” + [ENTER] + “FF Transmission” +
[ENTER] + “On” + [ENTER]
NOTE It is not possible to connect any external Fish Finder unit to the chart plotter.
5.2 UNDERSTANDING THE FISH FINDER PAGE
The display on chart plotters shows a history of time of the echoes received by the transducer.
The chart plotters have a menu that allows adjustments to receiver sensitivity, depth range and
scrolling speed of the Fish Finder display.