Chapter 6
CVS-833/833C
Using the Menu
6.7.2 Bottom Start (Specifying a depth for Bottom Detection)
This function avoids mistaken bottom detection from large school of fish by setting the inhibit depth for
bottom detection.
Initial setting: 1ft / m / J.fm / fm / l.fm
Setting range: 1
〜
400 ft or 1
〜
100m / J.fm / fm / l.fm
6.7.3 Draft (Matching to the boat’s draft)
This function is used for matching the depth of the emission line to the draft of your boat.
Initial setting: 0.0 ft / m / J.fm / fm / l.fm
Setting range: 0.0
〜
25.5 ft or 0.0
〜
10.0 m / J.fm / fm / l.fm
6.7.4 Panel Illum (Adjusting the operation panel illumination)
This function allows adjusting illumination of the operation panel when required.
Initial setting: 1/3
Setting range: 1/3 (darkest) - 3/3 (brightest), 3 steps
6.7.5 Mix Type (Selecting image-mixing mode)
Initial setting: Compare
Selectable mode: Compare and Subtraction
The image-mixing mode is an image processing function that enables weak fish like young sardines to
be better defined by comparing or subtracting the images from both the HIGH and LOW frequencies.
When echoes are detected by the HIGH frequency component, the sounder displays these echoes in a
preselected color to indicate small fish targets. This method utilizes the characteristic of ultrasonic wave
that small and weak fish echoes are sensitive to high frequency waves but are weak with a low
frequency waves. The MIX feature has two modes COMPARISON and SUBTRACTION.
COMPARISON mode:
This mode displays the result of the comparison between HIGH and LOW frequency echoes. If those
echoes are overlapped at the same depth, the resultant colors are displayed in mixed colors. However,
if the HIGH frequency echo is painted red (strongest color), the mixed color will also be red to show the
echoes are from small fish. If the mixed fish school is partly displayed with mixed colors among red
color, it suggests the possibility of a larger fish school among the small fish school.
SUBTRACTION mode:
This mode displays the resultant image by subtracting the HIGH frequency echoes from those of LOW
frequency. Using this method, you can discern a fish school by size. For instance, if the resultant
echoes are displayed in similar colors as the HIGH frequency echoes, this result suggests the majority
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