Simrad EK15 Reference Manual page 221

3
Maximum Depth
The search for the bottom echo extends down to this depth whenever bottom track
is lost. Use a slightly larger depth value than the deepest spot you expect to visit
in order to avoid annoyingly long ping intervals every time bottom track is lost. A
depth value of either 0 or less than the minimum depth disables the bottom detector.
Note
If you set maximum depth to a value identical or smaller than the minimum value,
the bottom detection algorithm will be disabled. The EK15 will then not be able to
detect the bottom at all, and the displayed depth will be 0.00 m
You can enter the desired
or by means of the spin box.
4
Bottom Backstep
The
Bottom Backstep
manually modify where on the bottom pulse the
depth shall be detected. The setting does not have
an effect on the EK15's ability to detect and track
the bottom.
The peak of the bottom pulse
a
Default bottom backstep level
b
Approximate bottom backstep level for flatfish
c
detection
Approximate bottom backstep level for seagrass detection
d
The bottom pulse basically identifies the bottom depth just prior to the peak of the
pulse (A). However, this may not be the true bottom. For example, if the bottom
pulse is generated by a rock bottom under a thick layer of mud, the actual depth is
slightly shallower. For this reason, the EK15 is by default set up to give you a depth
reading a few milliseconds before the peak of the pulse. This is done by setting the
bottom backstep level to a default value of -50 dB (B).
The actual bottom will never appear at the peak of the bottom pulse (A), it will
always be slightly before the peak. By changing the
can have the bottom detected earlier. This feature can for example be used when
you fish for flatfish, or when you are harvesting seagrass.
5
Apply to all
Click this box if you wish to implement your changes to all the echograms presently
in use on the EK15.
Related procedures
• Defining maximum and minimum depths on page 72
Related topics
• Active menu; functions and dialogs on page 205
351718/C
Maximum Depth
parameter allows you to
Functions and dialog boxes
value by dragging the slider up or down,
(CD010217-003)
Bottom Backstep
-30 dB
-50 dB
-70 dB
parameter you
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