Furuno FCR-2119-BB, Operation Manual

Page: 69 / 541

2. RADAR, CHART RADAR OPERATION
2-3
2.3.2 How to change the pulse length
1. Click the [Pulse] button at the top of the
InstantAccess bar™.
2. Click a pulse length.
2.4 How to Adjust the Sensitivity
The GAIN control (or [Gain] button) adjusts the sensitivity of the receiver. The proper
setting is such that the background noise is just visible on the screen. If you set up for
too little sensitivity, weak echoes may be missed. On the other hand excessive sensi-
tivity yields too much background noise; strong targets may be missed because of the
poor contrast between desired echoes and the background noise on the display.
Adjust the gain so background noise is just visible on the screen, using one of the fol-
lowing methods:
Control Unit : While monitoring the radar image and the gain slider bar, operate the
GAIN control to adjust the sensitivity.
Trackball module: For coarse adjustment, put the cursor within the slider bar area
then push the left button. For fine adjustment, put the cursor at the end of the slider
bar then roll the trackball while pushing and holding down the left button. Release the
button to finish.
2.5 How to Suppress Sea Clutter
Echoes from waves cover the central part of the display with random signals known
as sea clutter. The higher the waves, and the higher the antenna above the water, the
further the clutter will extend. When sea clutter masks the picture, suppress it with the
A/C SEA control (or [SEA] on the Status bar), either manually or automatically.
When both sea clutter and rain clutter are reduced, the sensitivity is decreased more
than when only one is adjusted. For that reason adjust them carefully.
The echo average is useful for reducing reflections from the sea surface. However,
high-speed targets are harder to detect than stationary ones when the echo average
is active.
Put cursor on slider bar and push and
hold left button. Drag cursor to new
location then release left button.