NorthStar Navigation EXPLORER 657 operation manual Sonar Bottom display, Sonar 50/200 display

9-3 Sonar Bottom display

A

B

AZoomed bottom signal B Sonar history

The display shows the sonar history on the right and the bottom signal as a flat trace in the center of the zoom section on the left. The flat trace make it easy to compare the echo strengths shown in the bottom signals. This can help to identify the type of bottom and objects close to the bottom.

The zoom bar on the far right shows the area of the history that is magnified in the zoom section:

•Use the or keys to adjust the zoom range.

•The 657 calculates the zoom depth automatically.

It is not necessary to turn Bottom lock on for this display.

9-4 Sonar 50/200 display

The display shows:

A the 50 kHz sonar history on the left

B the 200 kHz sonar history on the right.

Gain can be set independently for each frequency (see section 8-6). Range applies to both frequencies (see section 8-5).

AB

42 Northstar Explorer 657 Installation and Operation Manual