Simrad SD570, Operator'S Manual

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Simrad SD570
10 850--160137 / A
Figure 5 - OMNI/Vertical combination
The combination of the OMNI mode and the vertical slice, will
give an optimal visualizing of the catch situation. In addition
to the OMNI picture, the vertical slice is especially useful for
visualizing the vertical distribution of a school of fish. In that
way, it is not necessary to go over the target to see the
distribution on the echo sounder, which often results in a
spreading of the school.
When the optional stabilization system is installed in the
sonar, the transducer will be stabilized electronically for roll
and pitch up to approximately
±
30
°
. The stabilization may be
switched ON and OFF in the menu.
The OMNI/vertical combination is used in several display
modes to give the best situation overview for both purse seiners
and trawlers. In these presentations the seine net and the
trawl can be seen in relation to the vessel, the school of fish and
the bottom.
3.3 FM (Frequency Modulation)
In addition to the traditional single frequency transmitting
method, the SD 570 sonar is equipped with an FM correlation
mode.
In FM mode each transmission pulse contains up to 8 different
frequencies, and the receiver makes a spectrum analysis and
compares the received echoes with the transmitted frequency
code. This provides a filtering effect, which efficiently reduces
interference, noise and reverberation. In addition to giving a
clean and stable echo presentation, this also increases the
sonar’s detection range