Furuno FR-8111 - Manual (Page 40)

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3) Press the ENTER/SELECT key.
4) Select ECHO AVG and press the ENTER/SE-
LECT key.
5) Select 1, 2, or 3.
1: Distinguishes targets from sea clutter and
suppresses brilliance of unstable echoes.
2: Distinguishes small stationary targets such
as navigation buoys.
3: Displays distant targets as stable echoes.
6) Press the ENTER/SELECT key.
7) Press the MENU key.
a) Echo average OFF b) Echo average 1
Figure 1-26 Echo average
WARNING
Do not use the Echo Average feature
under heavy pitching or rolling; loss
of true targets may result.
Echo averaging uses scan-to-scan signal correla-
tion technique based on the true motion over the
ground of each target. Thus, small stationary tar-
gets such as buoys will be shown while suppress-
ing random echoes such as sea clutter. True echo
average is not however effective for picking up
small targets running at high speeds over the
ground.
The echo average feature is inoperable when a
heading signal is not available. If you wish to use
this feature without a heading signal, system ini-
tialization is required. (Consult a FURUNO rep-
resentative or dealer.)
Note: Echo averaging also requires ship’s speed
information from a log or manual entry.
1.31 Suppressing Second-Trace
Echoes
In certain situations, echoes from very distant
targets may appear as false echoes (second-track
echoes) on the screen. This occurs when the re-
turn echo is received one transmission cycle later,
namely, after a next radar pulse has been trans-
mitted.
To suppress them, turn on 2ND ECHO on the
ECHO SIG menu.
1) Press the MENU key.
2) Select the ECHO SIG menu.
3) Press the ENTER/SELECT key.
4) Select 2ND ECHO and press the ENTER/SE-
LECT key.
5) Select ON.
6) Press the ENTER/SELECT key.
7) Press the MENU key.