Simrad EQ42 Manual page 71

EQ42/50/52 Glossary of terms
Ping to ping filter – can be set to either on or off. With the filter "off", then each
received echo will be reflected on the screen. Whereas with the filter "ON", the
system will compare every two echoes received and only reflect on the screen
what is received from both echoes, which will give a more uncluttered and
precise presentation.
Pulse length – the transmitted pulse length can be set to OFF for observing noise
in the water (Auto range will switch to manual mode). Set to AUTO, the
optimum setting will be applied according to the water depth. Or it can be set
manually, if a specific pulse length is required:
SHORT less than 10m deep water
MEDIUM between 10 and 50 m deep water
LONG more than 50m deep water
A long pulse will reach deeper but give less resolution.
Range – refers to the distance shown from the top to the bottom of the display
screen. Selecting Auto range will cause the EQXX to change the basic range
setting(s) to keep the displayed bottom in the lower half of the display. For
instance, as your boat moves into deeper waters, the EQXX will automatically
switch to a deeper range, always keeping the displayed bottom in the lower half
of the display. Manual range allows the operator to select a specific range.
Range start – allows the user to set the displayed depth range to begin at some
point below the surface. For example, a 100 meter displayed range can be
"phased" downwards, so that the screen shows a 100 meter section beginning at,
say, 200 meters and going to 300 meters depth.
Scroll speed – is the rate of movement of the targets on the display screen,
moving from right to left. It is adjustable, to allow the user to show a longer
"history" on the display screen, if desired.
Scroll synchronization – the screen can be updated on the basis of time or
distance (when data from last ping appears on the display).
Signal threshold – can be set to ON to eliminate the appearance of unwanted
noise. The threshold level is automatic and the feature should be used with cau-
tion, as it may eliminate small fish and small unidentified objects on the screen.
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Appendix A