User manual NAVMAN FISHFINDER F400

[. . . ] remember , the transducer location is the most critical part of the installation. If this is not done properly, the transducer can't perform at its designed potential. Therefore the performance of the fishfinder, especially at higher speeds, will not be satisfactory. Once the best location of the transducer is determined, hold the transducer and bracket against the transom. [. . . ] In the Autofish mode, unnecessary surface noise is reduced from the top of the screen. This mode is recommended when your boat is moving along at higher speeds. This feature displays an intensity graph of the current echoes down the right hand side of the screen. The information can be used to help determine the type of bottom structure and the size of fish. The strength of the echo is proportional to size or number of pixels visible in the analogue section of the screen. This feature will help to determine the strength of the return echo from the bottom and therefore how hard or soft the bottom may be. In this mode the depth, speed and temperature are displayed in large easily readable digits. The log will display the total distance in the speed unit you have selected. The log total is automatically stored in memory when the power is switched off or removed but this value can be reset to zero (see SETUP menu). When either or all of the Fish (F), Shallow (S) or Deep (D) alarms are active they are displayed at the top left corner of the screen. If Top is selected then a lower depth limit value must also be selected. This mode locks the display to show only echoes from the surface of the water down to the lower depth limit you have selected. This means that the sea bed may not be shown if the water is deeper than the selected lower depth limit. This mode locks the display to show only echoes between the sea bed and the upper depth limit you have selected. The top of the water may not be shown if the water is deeper than the upper depth limit. This feature is like a ZOOM function, as it allows you to see the bottom contour and fish echoes above the bottom in greater detail. If All is selected then the unit will automatically adjust the display range to show both the top of the water and the sea bed no matter what the depth of the water is. Press either the key or the key to move the pointer to the desired mode of operation Press the key to accept the choice and return to normal display mode Press either the key or the key to move the pointer to the desired mode of operation If the desired mode is Top or Bottom then use the V or the ^ key to adjust the limit value to the desired level key to accept the choice Press the and return to normal display The higher the gain setting, the better the unit is able to pick up weak return signals. Deep water operation requires the gain to be set to a higher value due to loss of signal in the water. If Manual is selected then a gain setting from 0 to 15 must also be entered. This will be the value of gain that is always used when displaying information on the screen. A low gain number may be suitable in shallow water but will need to be increased for deep water operation If Auto is selected then the gain will automatically vary as the water depth changes. [. . . ] The Fishfinder thus eliminates weaker signals such as fish or even the sea bed from the display. Manual gain may be set too low, if you have the instrument set in manual mode. The water may be deeper than the Fishfinder's ability to find the bottom. If it cannot find the bottom return signal while it is in the automatic mode, the display will flash continuously. [. . . ]