How The Explorer 443D/443Df Works; Basic Operation - NorthStar EXPLORER 443D Installation And Operation Manual

1-2 How the Explorer 443d/443df works

The Explorer 443d/443df has two parts:
- the transducer attached to the hull
- the display unit.
The transducer generates an ultrasonic pulse
(sound that is above the hearing range of
the human ear), which travels down towards
the bottom at a speed of about 4800 ft/sec
(1463 m/sec), spreading out into a cone shape.
When the pulse meets an object, such as a fish or
the bottom, it is partly reflected back up towards
the boat as an echo. The depth of the object or
bottom is calculated by the Explorer 443d/443df
by measuring the time taken between sending a
pulse and receiving the echo. When an echo has
been returned, the next pulse is sent.
The Explorer 443d/443df converts each echo
into an electronic signal, displayed as a vertical
line of pixels. The most recent echo appears on

2 Basic Operation

Key Names
ESC
DISP
,
,
MENU Press to show the Options menu on a display; press
ENT
+
—
AUTO Select fishing/cruising or manual operating mode
Northstar Explorer 443d/443df Installation and Operation Manual
the extreme right of the display, with the older
echoes being scrolled towards the left, eventually
disappearing off the display.
The scroll speed depends upon the water depth
and scroll speed setting. See section 3-2 Setup >
Sonar and section 4-1 Interpreting the display, for
more information.
The appearance of echoes displayed are affected
by:
the fishfinder settings (frequency selected,
•
range and gain settings)
echoes (different fish types, different bottom
•
types, wrecks and seaweed)
noise (water clarity and bubbles).
•
See section 4-1 Interpreting the display, for more
information.
If a menu is not displayed then go to the sonar
display. If a menu is displayed then cancel any
changes and return to the previous menu.
Shows the Display menu.
Cursor keys move the selection highlight and
change settings.
again to show the Setup menu.
Confirms any changes or from a sonar display shows
the Gain controls.
Increases the Range.
Decreases the Range.
Powers On and Off; shows the Backlight control.
7