Furuno CSH-83, CSH-84 manual Adjusting Beamwidth, Setting Noise limiter data setting window Signal

Setting Noise limiter (data setting window: SIGNAL,

SIGNAL PROCESS)

Weak, unwanted reflections, colored light-blue or green, appear when the water is dirty, plankton layers exists, or due to ship’s noise. The noise limiter (NL) can reduce the effects of these unwanted reflections–raising the setting causes them to become bluish to background color. Normally a setting of 3 or 4 is suffi- cient.

Adjusting Beamwidth

Beamwidth can be adjusted at SONR•BEAM, BEAM on the data setting window.

Table 3-1 Beamwidth adjustment menus

Menu	Application
	Set to "0" for normal use. The higher the setting the
HOR	narrower the beam. This control may be used
	together with the AGC and NL controls to suppress
	sea surface reflections and seabed echoes.
	In case of TX Frequency 75, 81 and 88 kHz.
	0: This is standard setting. Use for normal
	conditions.
	1: This is to suppress the seasurface noises (weak).
	Between tilt angle 0° and 13°, the lower the tilt
	angle, the stronger the AGC for near range.
	2: Same as above "1", but AGC is more effective.
	3: Sane as above "1", but AGC is effective between
	tilt angle -5°and 60°.
	4. Same as above "3", but AGC is more effective.
	In case of TX Frequency 94 and 107 kHz.
	0: This is standard setting. Use for normal
VER	conditions.
	1: This is used for detecting far range. The output
	power goes up and the gain (TVG) of near range
	is supprened.
	2: This is used for improving the presentation. The
	output pulselength is shorten and the receiving
	gain goes up.
	3. This is to suppress the surface voises. TVG
	effective area changes as follows;
	Near: 0 to 100 m
	Medium: 25 to 400 m
	Far: More than 100 m
	4: The vertical beamwidth for TX and RX goes
	wider than normal.

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