Humminbird 128 manual Menu Functions, Senstivity

Once a menu times out, it is still considered the active menu. Pressing MENU will bring up the last used menu.

The UP ARROW and DOWN ARROW make adjustments to menu functions. On the left side of every menu there are UP ARROW and DOWN ARROW symbols. The symbols indicate which ARROW button has a function in a particular situation. Either one or both ARROW buttons can be used to adjust the menu function. A hollow ARROW symbol means that the corresponding ARROW button has no function. Pressing that button will result in no adjustment and the "error" audible will be heard. A solid ARROW symbol means that the corresponding ARROW button can be used to affect the menu adjustment.

The ARROW buttons often can be used when no menu is on-screen. In these situations, pressing the ARROW button affects the function of the active (last-used) menu. This is a short-cut to menu operation. The menu appears onscreen while the adjustment is made and 'times out'. A frequently used menu can be adjusted very quickly using this technique.

After an adjustment is made to a menu function, the menu "times out" after several seconds and the unit returns to normal operation.

All menus use the same basic layout as shown in Figure F. The heading at the top describes the menu function (see Control Functions for more details on individual functions). The UP ARROW and DOWN ARROW symbols to the left of the menu indicate which buttons are available for adjustment. In menus which have numerous possible settings such as depth range, a range of adjustment indicator shows the total range available and the current setting. Within the menu are the options available. The selected option or current setting is highlighted in the black

box. If no adjustment is made, this will be the selected setting. Pressing one of the ARROW buttons while the menu is on-screen selects another option.

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

Senstivity

The Sensitivity function controls the sensitivity of the sonar receiver. The Wide 128 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 biasing this Sensitivity adjustment either higher or lower based on personal preference. You can select one of 11 sensitivity bias settings from -5 to +5. A bias setting of 0 (Factory Setting) has no effect on the automatic sensitivity control. Increasing the bias (+1 through +5) causes the

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

In murky or muddy water, it is often advantageous to reduce the sensitivity bias. 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 desirable to increase the sensitivity bias since even the smallest sonar return may be of interest to the user.