Noise Filter (Advanced); Max Depth (Advanced, 2D Sonar Views Only); Water Type (Advanced) - Humminbird 748 3D Operation Manual

Noise Filter adjusts the sonar Noise Filter to limit interference on the display from
sources such as your boat engine, turbulence, or other sonar devices.
The Off setting removes all filtering. Low, Medium, High 1, High 2, and High 3
settings add progressive filtering of the sonar returns. High 1, High 2, and High 3
are useful when there is excessive trolling motor noise, but in some deep water
situations, the High settings may actually hinder your unit's ability to find the
bottom.
Max Depth controls the maximum depth of operation. When Max Depth is set to
Auto, the Fishing System will acquire bottom readings as needed (within the
capacity of the unit). When Max Depth is set to match your fishing maximum
depth, your Fishing System will not attempt to acquire sonar data below that
depth, so more detail will be shown on the screen.
NOTE: If the bottom is deeper than the Max Depth setting, the digital depth readout
will flash, indicating that the Fishing System cannot locate the bottom.
Water Type configures your unit for operation in fresh or salt water. In salt water,
you can also choose the shallow or deep setting.
Water Type affects the accuracy of deep water depth readings. In salt water, what
would be considered a large fish might be 2 to 10 times bigger than a large fish in
fresh water (depending on the type of fish you are seeking). The salt water setting
allows for a greater range in fish size adjustment to account for this difference.
Sonar Menu Tab
Noise Filter
(Advanced)
Settings: Off, Low, Medium, High 1, High 2, High 3,
Default = Low
Max Depth
(Advanced, 2D Sonar Views only)
Settings: Auto, 10 to 1000 ft, 3 to 330 m [International
Models only], Default = Auto
Water Type
(Advanced)
Settings: Fresh, Salt (shallow), Salt (deep), Default = Fresh
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