Furuno CH-250 - Manual (Page 63)

3-13
CLUTTER:
Low intensity echoes, often caused by sediments in water, are painted on the
screen as a large number of random dots. The higher the number (setting) the weaker the
echoes which are erased.
HORZ RANGE:
You may choose the horizontal range expansion factor for the vertical scan
picture, from x1 or x2. Note that this feature cannot be adjusted when the vertical search mode,
activated by a function key, is turned on.
3.13 Interpreting the Vertical Fan Display
This section provides information necessary for interpreting the vertical fan display.
3.13.1 How the vertical fan mode picture is painted
The sounding beam is emitted and the information (target echoes) obtained by the beam
appears in the corresponding sector as it appears on the sonar mode. The difference is that the
training is performed only in vertical direction. It forms a sounding area of a half-circle (like a
slice of watermelon) to observe a vertical section of underwater conditions.
The bearing of the vertical sounding beam can be selected manually or automatically.
Sounding Beam Screen Display
Freq: 60 kHz
0
°
(1) Bearing of the
sounding beam
Bow
180
°
0
°
Tilting direction
(2) Sector center
(3) Display area
Select the bearing of the sounding beam (1) by [TRAIN]
control, the sounding sector center (2) by the [TILT] con-
trol and the display area (3) by the [SECTOR] control.
(1) Bearing of the
sounding beam
180
°
(2) Sector center,
(3) Display area
Sector center 90
°.
Display range
24
°.
Figure 3-17 How the vertical fan mode picture is painted