Si-tex ES502, Руководство пользователя

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37 User Manual
6.7.3 Auto-range fails in very deep waters displaying a digital very
shallow depth readout. What should I do?
The Fish Finder capability to detect the bottom decreases as the bottom depth
increase. If the bottom composition is soft as mud, if the sea conditions are bad,
if there are thermoclines or the water is full of materials in suspension it can
further decrease thus causing the digital depth readout to fail. When this happens
the auto-range algorithm also fails. To recover from this situation it is necessary
to switch to manual range mode and to set the manual depth mode. When manual
depth mode is selected the algorithm that calculates the digital depth readout
searches for the bottom within the range manually selected by the user. At this
point it is necessary to increase manually the range until the bottom becomes
graphically visible. If the echoes from the bottom are strong enough, the Fish
Finder shall look to the bottom giving a correct depth reading and shall be pos-
sible to return in auto range mode. Please note that if one or more of the condi-
tions that reduce the echoes from the bottom listed above is true the bottom may
be not visible at all, in this situation a strong thermocline or surface clutter may
be interpreted by the Fish Finder as the bottom.
6.8 At a very shallow range upper half of the screen appears
almost completely filled by the Surface Clutter. How can
I eliminate it?
This is normal in shallow waters. To clean up the surface clutter without degrading
the digital depth readout algorithm functionality there are two modes: 1) if Sur-
face Declutter = OFF, it is possible to set the STC value to custom setting the STC
length to the same size of the surface clutter, and increasing the STC strength
until the image on the screen cleans up. Please note that in very shallow waters
it is usually better to switch to manual gain mode to reduce gain fluctuation due to
rapidly changing bottom conditions. 2) Using Surface Declutter, increase the Sur-
face Declutter value until the surface declutter disappears completely.
6.9 Why do I never see fishes in the range between 0 to 0.7
meters?
The minimum range of the Fish Finder is 0.7 meters. In this interval the Fish
Finder can detect neither the bottom nor any target.
6.10 How can I reduce the Surface Clutter?
You can act by: properly setting the STC as described at 6.12 and also by increas-
ing the NOISE LEVEL and reducing the GAIN or the GAIN OFFSET (if you are in
auto gain mode). However please note that a strong attenuation of Surface Clutter
may also reduce the capability to detect targets.
6.11 The Fish Finder is in auto gain mode but the picture
displays too many small targets, what shall I do to reduce
the screen clutter?
Try increasing the NOISE LEVEL or decreasing the GAIN OFFSET.
6.12 In very shallow waters when the AUTO GAIN mode is
selected there are fluctuations in the bottom profile
width and its color representation. What should I do?
In very shallow waters the environment situation (bottom/water condition) vary
very quickly thus causing the auto gain algorithm to create oscillations while