Furuno 1761 MARK-3 - Manual (Page 19)

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2.19 Echo Stretch
Normally, the reflected echoes from long dis-
tance targets appear on the screen as weaker
and smaller blips even through they are com-
pensated by the radar’s internal circuitry. The
Echo Stretch function magnifies these small
blips.
1. Press the [MENU] key to open the menu.
2. Operate the trackball to select “1. ECHO
STRETCH”.
3. Press the [RANGE] key to select “ON”.
The indication “ES” appears at the upper
right-hand side of the screen and the echoes
are doubled lengthwise.
To turn off the echo stretch, select “OFF” on
the MENU display.
Note 1: This function magnifies not only tar-
gets but also sea clutter and radar interfer-
ence are properly adjusted before activating
the echo stretch.
Note 2: This function is inactivate on short
ranges, that is 0.25 to 1 nautical miles. “ES”
appears in reverse video when the echo
stretch is turned on in those ranges.
2.20 Suppressing Radar
Interference
Radar interference may occur when near an-
other shipborne radar operating in the same
frequency band as your radar. Its on-screen
appearance is many bright dots either scat-
tered at random or in the form of dotted lines
extending from the center (or the edge) to
the edge (or the center) of the display. Fig-
ure 2-11 illustrates interference in the form
of curved spokes, Interference effects are
distinguishable from normal echoes because
they do not appear in the same place on suc-
cessive rotations of the scanner.
Figure 2-10 Radar interference
1. Press the [MENU] key to open the menu.
2. Operate the trackball to select “2. I. RE-
JECT”.
3. Press the [RANGE] key to select “ON”.
(Factory setting is ON.)
The indication “IR” appears at the upper right-
hand side of the screen. Press the [MENU]
key again to erase the menu display.
2.21 Adjusting Control Panel
Brilliance
Adjusts the backlighting of the front panel in
five steps.
1. Press the [MENU] key to open the menu.
2. Operate the trackball to select “3. PANEL
DIMMER”.
3. Press the [RANGE] key to select level de-
sired.
4. Press the [MENU] key again to erase the
menu.