Humminbird 405SX manual Menu Functions, Sensitivity. The Sensitivity function controls

High Sensitivity (+) Sensitivity at “0”

USING THE 405SX

MENU FUNCTIONS

Several of the menus are multi-step. In some situations if an adjustment is made, additional options become available for further adjustment. Examples of these multi-step menus are Depth Range, Depth Alarm and Zoom. See the detailed description of each function for further explanation.

Menu Functions

Sensitivity. The Sensitivity function controls the

sensitivity of the sonar receiver. The 405SX automatically adjusts the level of receiver sensitivity based on a number of factors including

the depth of the water and the level of noise present. Noise can be caused by other electronic

devices, engines, trolling motors, propeller cavitation and hydrodynamic flow among others. The user has the option of adjusting the Sensitivity higher or lower based on personal preference. You can select one of 11 sensitivity settings from -5 to +5. A setting of 0 (factory setting) has no effect on the auto-

matic sensitivity control. Increasing the sensitivity (+1 through +5) enables the unit to display the information from progressively smaller sonar returns. By decreasing the sensitivity (-1 through -5), the unit effectively filters small sonar

returns.

In murky or muddy water, it is often helpful to reduce the sensitivity. This prevents the display from being cluttered with sonar returns from debris or suspended particles. In very clear or very deep water, it may be helpful to increase the sensitivity since even the

smallest sonar return may be of
interest to the user.	Low Sensitivity (-)

To adjust Sensitivity, press MENU repeatedly until the Sensitivity heading is displayed. When the Sensitivity menu appears, use the UP ARROW to increase the sensitivity, or the DOWN ARROW to reduce sensitivity. To sequence through the available settings, press and hold either ARROW button. Release the button at the setting you want to select.

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