Simrad SD570, Operator'S Manual, Page: 81 / 128

Operation
33
850--160139 / A
5.12 Track window
This function is only used when target tracking is selected.
TRACKWINDOW:
SMALL
*MEDIUM
LARGE
The selected target window is presented on the bearing line. As
the sonar will follow the strongest echo inside this window, it is
used to prevent the sonar from locking to surface or bottom
echoes close to the desired echo. The window is automatically
centred on the strongest part of the echo.
The size of the window is normally set to MEDIUM, but if the
target is small and the surroundings full of noise, a SMALL
window should be selected. However, if the target is large, a
LARGE window is preferred.
(CD3988)
When the stabilization is used, this also allows the use of the PP
filter in rough seas. This will give a cleaner and more stable echo
presentation.