Furuno CH-37 - Manual (Page 34)

2-18
2.18 Interpreting the Display
This section provides the information necessary for interpret-
ing the display.
How the 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 45
°
sector of the screen. Thus, all directions around the boat
are s ounded in 8 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 times
of transmissions are required to complete full 360
°
pic-
ture (6
°
x 60 = 360
°
). This means that sounding speed
reduces. However, since transmission power is concen-
trated into the narrow sounding beam, a superior detec-
tion range is obtained. Furthermore, since the bottom
contour is painted distinctly, bottom fish detection may
become easier.
Sounding Beam Screen Display
Freq: 60 kHz
When the narrow sounding beam (6-degree step operation) is selected, 60 transmissions
are required to complete the full circle detection.
Tilt
θ
Sounding
Beam
TX
RX
Tilt:
θ
60
°
/16
°
13
°
16
°
13
°
45
°
*
Figure 2-16 How the picture is painted