Lowrance electronic LMS-339cDF iGPS GPS Receiver User Manual


 
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Sensitivity & Auto Sensitivity
The sensitivity controls the ability of the unit to pick up echoes. Sensi-
tivity can be adjusted, because water conditions vary greatly. A low
sensitivity level (from zero to 50 percent) excludes much of the bottom
information, fish signals, and other target information.
High sensitivity levels let you see this detail, but it can also clutter the
screen with many undesired signals. Typically, the best sensitivity level
shows a good solid bottom signal with Colorline and some surface clutter.
Automatic Sensitivity
The default sensitivity mode is automatic. The unit bases the sensitiv-
ity level on water depth and conditions. When the unit is in the auto-
matic mode, sensitivity is automatically adjusted to keep a solid bottom
signal displayed, plus a little more power. This gives it the capability to
show fish and other detail.
However, situations occur when it becomes necessary to increase or de-
crease the sensitivity. This typically happens when you want to see
more detail, so an increase in sensitivity is indicated. Or, wave action
and boat wakes can create enough tiny air bubbles to clutter much of
the water column. In that case, a decrease in sensitivity is indicated to
reduce some of the clutter.
The control bar used to adjust sensitivity up or down is the same
whether the unit is in the automatic or manual mode. In automatic you
can adjust sensitivity up to 100 percent but the unit will limit your
minimum setting. In auto, the unit will continue to make small ad-
justments, allowing for the setting you selected.
In manual mode, you have complete control over sensitivity, with the
ability to set it anywhere from zero to 100 percent. Once you select a
level in manual, the unit will continue to use that exact sensitivity set-
ting until you change it or revert to auto mode.
To adjust sensitivity in auto mode:
1. Press
MENU|ENT.
2. The Sensitivity Control Bar appears. Press adjust sensitivity.
When it's set at the desired level, press
EXIT.
Tip:
For quicker sensitivity adjustments, try leaving the Sensitivity
Control Bar on the screen as the chart scrolls. You can see the
changes on the screen as you press the up or down arrows. This is
handy when there's a lot of clutter in the water, and you are
matching the sensitivity to rapidly changing water conditions.