Furuno CH-250 Interpreting the Horizontal Display, How the horizontal mode picture is painted

2.14 Interpreting the Horizontal Display

This section provides information necessary for interpreting the horizontal display.

2.14.1 How the horizontal mode picture is painted

The wide sounding beam is emitted from the soundome at a certain tilt angle (see hatched area in the figure below). The information (target echoes) obtained by this beam is displayed in sectors of increments of 12° of the screen. Thus, all directions around the boat are sounded in 30 times of transmissions.

Note: When the “FAST SCAN” is switched off, the equipment operates in a narrow sounding beam. Then, the echoes appear on a 6° sector in each transmission, so 60 transmissions are required to complete the full 360° picture (6° x 60=360° ). This means that training speed is slower. However, since transmission power is concentrated into the narrow sounding beam, a superior detection range is obtained. Furthermore, since the bottom contour is painted distinctly, bottom fish may be more easily detected.

Sounding Beam Screen Display

Tilt: θ	Train: 6˚*
	Tilt: θ

Sounding

Beam

When the narrow sounding beam (6˚)

is selected 60 transmissions are required to complete the full circle.

*12˚ When high speed training is selected.

Figure 2-20 How the horizontal mode picture is painted

2-23