Furuno GP-1650F, GP-1650DF manual 11-9, System Setup soft key, System Setup menu description

4.Select a range, ZOOM RANGE or B/L RANGE, and press the soft key EDIT. ZOOM RANGE selects the range to zoom in the marker and bottom zoom modes. The setting range is 7 to 5000 feet, and the default setting is 30 feet. B/L RANGE sets the expansion width for the bottom- lock display, 10 or 20 feet. The default setting is 20 feet.

5.Adjust the range with the cursor pad.

6.Press the soft key RETURN to go back to the RANGE SETUP menu.

SYSTEM SETUP soft key

The system setup menu provides functions for selection of fish alarm sensitivity, TX power selection, TVG adjustment, echo level offset and seabed echo offset.

1.Press the [MENU] key.

2.Press the soft key SOUNDER SETUP OPTIONS.

3.Press the soft key SYSTEM SETUP.

			SYSTEM
	sFISH ALM LVL	NORMAL	SETUP
	TX POWER	ON
	TVG 200kHz	5	EDIT
	TVG 50kHz	5
	ECHO OFFSET 200kHz	+00
	ECHO OFFSET 50kHz	+00
	SEABED LVL 200kHz	80
	SEABED LVL 50kHz	80
DGPS 3D			RETURN

Figure 11-16 System setup menu

SYSTEM SETUP menu description

FISH ALM LVL: Sets the fish alarm sensitiv- ity; namely, which echo strength will trigger the alarm. HIGH, only the strongest echoes trigger the alarm; NORMAL, echoes from strong to medium strength trigger the alarm, LOW, any echo triggers the alarm. The de- fault setting is NORMAL.

TX POWER: Turns TX power on/off. The default setting is ON.

TVG 200kHz, TVG 50kHz: TVG (Time Var- ied Gain) compensates for propagation at- tenuation of the ultrasonic waves. It does this by equalizing echo presentation so that fish schools of the same size appear in the same density in both shallow and deep waters. In addition, it reduces surface noise. Note that if the TVG level is set too high short range echoes may not be displayed.

Fish school A

Fish school B

Figure 11-17 TVG concept

ECHO OFFSET 200kHz, ECHO OFFSET 50kHz:

If the on-screen echo level appears to be too weak or too strong and the level cannot be adjusted satisfactorily with the gain control, adjust echo offset to compensate for too weak or strong echoes. The default setting for both 200 kHz and 50 kHz is zero.

SEABED LVL 200kHz, SEABED LVL 50kHz:

If the depth indication is unstable in automatic operation or the bottom echo cannot be dis- played in reddish-brown by adjusting the gain control in manual operation, you may adjust the bottom echo level detection circuit, for both 50 kHz and 200 kHz, to stabilize the in- dication. Note that if the level is set too low weak echoes may be missed and if set too high the depth indication will not be displayed. The default setting for both 200 kHz and 50 kHz is 80.

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