Humminbird SINGLEBEAM 405SX User manual

405SX SINGLEBEAM
OPERATIONS MANUAL
fishfinder

THANK YOU FOR CHOOSING YOUR 405SX FISHFINDER, MADE BY
TECHSONIC INDUSTRIES, MANUFACTURER OF AMERICA’S #1 NAME IN
FISHFINDERS, HUMMINBIRD. HUMMINBIRD HAS BUILT ITS REPUTATION
BY DESIGNING AND MANUFACTURING TOP QUALITY, THOROUGHLY
RELIABLE MARINE EQUIPMENT. YOUR HUMMINBIRD PRODUCT IS
DESIGNED FOR TROUBLE-FREE USE IN EVEN THE HARSHEST MARINE
ENVIRONMENT.
IN THE UNLIKELY EVENT THAT YOUR HUMMINBIRD DOES REQUIRE
REPAIRS, WE OFFER AN EXCLUSIVE SERVICE GUARANTEE. COMPLETE
DETAILS ARE INCLUDED AT THE END OF THIS MANUAL.
WE ENCOURAGE YOU TO READ THIS OPERATIONS MANUAL CAREFULLY
IN ORDER TO GET FULL BENEFIT FROM ALL THE FEATURES AND USES OF
YOUR Humminbird PRODUCT.
WARNING! THIS DEVICE SHOULD NOT BE USED AS A
NAVIGATIONAL AID TO PREVENT COLLISION, GROUNDING,
BOAT DAMAGE, OR PERSONAL INJURY. WHEN THE BOAT IS
MOVING, WATER DEPTH MAY CHANGE TOO QUICKLY TO
ALLOW TIME FOR YOU TO REACT. ALWAYS OPERATE THE BOAT
AT VERY SLOW SPEEDS IF YOU SUSPECT SHALLOW WATER OR
SUBMERGED OBJECTS.
THANK YOU
WARNING: Dis-assembly and repair of this electronic unit should only be performed by authorized
service personnel. Any modification of the serial number or attempt to repair the original equipment or
accessories by unauthorized individuals will void the warranty. Handling and/or opening this unit may
result in exposure to lead, in the form of solder.
WARNING: This product contains lead, a chemical known to the State of California to
cause cancer and birth defects and other reproductive harm.

Section 1: Installation preparation . . . . . . . . . . . . . . . . . . . 2
Parts Supplied . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Installation Overview . . . . . . . . . . . . . . . . . . . . . . . . . 2
Alternative Transducers and Mounting Methods. . . . . . 4
Beginning Installation . . . . . . . . . . . . . . . . . . . . . . . . . 5
Section 2: USING THE 405SX. . . . . . . . . . . . . . . . . . . . . . . 6
How Sonar Works . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Simulator Operation . . . . . . . . . . . . . . . . . . . . . . . . . . 6
What You See On Screen . . . . . . . . . . . . . . . . . . . 7–11
Control Functions . . . . . . . . . . . . . . . . . . . . . . . . 11–15
Menu Functions . . . . . . . . . . . . . . . . . . . . . . . . . 15–25
Section 3: ADVANCED FEATURES. . . . . . . . . . . . . . . . . . . 24
Using Diagnostic . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Section 5: MAINTENANCE/WARRANTY. . . . . . . . . . . . . . . 25
Maintenance and Troubleshooting . . . . . . . . . . . . 26–28
Warranty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Service Policy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Customer Service . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
TABLE OF CONTENTS
Rev 10416E

2
INSTALLATION PREPARATION
PARTS SUPPLIED
PARTS SUPPLIED
Before installing your 405SX, please ensure the following parts are included in
the box:
•405SX fishfinder
•Transducer with 20' of cable and mounting hardware kit
•Mounting system and mounting hardware kit
•6' power cable
•Publications kit
Note: The 405SX includes a temperature sensor and the 405SX+
includes speed and temperature sensors with appropriate
hardware and instructions for installation.
If any of these items is missing contact your local dealer.
ACCESSORIES
Humminbird offers a wide assortment of accessories that complement and
expand the capability of your new 405SX. These accessories are designed with
the same high standards. The Humminbird Accessory catalog included with
your unit contains descriptions of the many accessories available and ordering
information. All Humminbird accessories are available through your full-service
Humminbird dealer.
INSTALLATION OVERVIEW
The 405SX consists of two primary components to install: the control head and
the transducer.
The control head contains the sonar transmit and receive circuitry, as well as the
user controls and display. It should be installed in a location that provides access
to the controls and visibility while in use. The control head mounts on a quick
disconnect mounting system that swivels and tilts, providing flexibility for
viewing from almost anywhere on the boat.

3
INSTALLATION PREPARATION
INSTALLATION OVERVIEW
The transducer converts electrical energy from the transmitter into mechanical
pulses or sound waves. The transducer also receives the reflected sound waves
and converts them back into electrical signals for display on the control head. It
should be installed in contact with the surface of the water in an area that has
smooth water flow - usually on the transom of the boat. There are several
mounting options for the transducer. Review the
following section to determine the method that
works for you and your boat.
Determining How to Mount the
Transducer
The 405SX includes a model XT-6-24 transducer.
This transducer can be mounted on the transom
of the boat, or bonded to the inside of a
fiberglass hull boat.
The transom installation, which is the most
widely used, places the transducer on the outside
of the boat hull. This technique produces the
least signal loss, and provides a way to adjust the
transducer after installation. The mounting
hardware included is designed to
protect both the boat and the
transducer should the boat strike
debris in the water or when trailering.
As an alternative to transom mounting,
it is possible on many fiberglass-hulled
boats to glue the transducer on the
inside of the boat hull. Since fiberglass
has similar sonar characteristics as
water, the sonar signal can pass
through the boat hull with minimal
loss. The hull of the boat must be single
layer construction (not double-hulled).
Also, any air trapped in the lamination
of the fiberglass would prevent the
sonar signal from passing through.
Inside the Hull Mounted Transducer
Transom Mounted Transducer
For additional details reference the
TRANSDUCER INSTALLATION section of
the enclosed Installation Sheet.

4
Inside the hull installations require no holes to be drilled into the boat and
through experimentation, high-speed operation comparable to transom
mounting can be achieved. Two part, slow cure epoxy is required to glue the
transducer in place.
ALTERNATE TRANSDUCERS AND MOUNTING METHODS
The 405SX comes with everything necessary for installation and operation on
most boats. However, there are several situations which may require a different
type of transducer. Inboard boats, wood or metal hulls, and sail boats create
unique transducer mounting needs. Alternate transducers and mounting
methods are detailed below.
Portable Mounting
The standard transducer can be adapted for
portable installations using part number MHX-PT2.
This accessory adapts your transducer to a suction
cup mount for temporary installation on the boat
hull or other surface.
Trolling Motor Mounting
The standard transducer can also be adapted to
mount on most trolling motors using part number
AD-STM-7. This accessory includes a bracket and
hose clamp that allows mounting the transducer to
the body of most trolling motors.
TRANSDUCER EXCHANGE
Other transducers are available as replacements for
the standard transducer. You may exchange your
new and unassembled transducer for another type
by returning it to the address listed in Customer
Support. Some transducers may have additional costs. Refer to the Accessory
catalog or call Customer Support for information.
INSTALLATION PREPARATION
ALTERNATE TRANSDUCERS AND MOUNTING METHODS

BEGINNING INSTALLATION
Now that you have determined the transducer mounting method, you can
begin installation of the 405SX. The fold out installation guide included
provides detailed step by step instructions for installation of the control head
and transducer. For transom mount transducer installations, you will need the
mounting template at the back of this manual.
In addition to the parts included you need the following for installation and
operation:
•A powered hand drill and various drill bits
•Phillips and flat-head screw drivers
•A ruler or measuring tape
•Pen or pencil
•12 volt power source (your boat’s battery)
•A 1-amp fuse
•A fuse holder (if you are wiring directly to the boat’s battery)
•Silicone sealant (for sealing drilled holes)
•2-part, slow-cure epoxy (for inside the hull transducer installations)
INSTALLATION PREPARATION
BEGINNING INSTALLATION
5
Note: If you have purchased the 405SX+you will have in addition
to the parts and instructions above:
•Speed and Temperature sensors
•Instructions for installing speed and temperature sensors
•Appropriate hardware to mount sensors

USING THE 405SX
HOW SONAR WORKS
6
HOW SONAR WORKS
Your Humminbird unit uses sonar to
locate and define underwater objects,
define the bottom terrain, as well as
determine distance.
Sonar technology is based on sound
waves. Your Humminbird unit sends out
a sound wave signal. With this signal it
determines distance by measuring the
time between the transmission of the
sound wave and when the sound wave
is reflected off an object. Your
Humminbird uses the reflected signal to
interpret location, size and composition
of an object.
Sonar is very fast. A sound wave can travel from the surface to a depth of 600'
and back again in less than ¹⁄₄ of a second. It is unlikely that your boat can
"outrun" this sonar signal.
The 405SX is a 200 kHz, single-beam fishfinder. The 200 kHz frequency
provides excellent sonar resolution (the ability to distinguish small returns or
returns which are close to the bottom), while providing depth capabilities to
600’. The shape of the sonar beam is symmetrical and covers an area of
approximately 24 degrees side to side and front to rear.
Actual depth capability depends on factors such as bottom hardness, water
conditions, and transducer installation. Units will typically read to deeper
depths in fresh water than in salt water.
SIMULATOR OPERATION
The 405SX contains a simulator that allows you to use the unit as if you are on the
water. The simulator is invaluable for learning how to operate the 405SX.
There are two ways to start the simulator. If the unit is powered off, press and hold
the POWER button for approximately three seconds until you hear a continuous chirp.
The simulator can also be started by selecting the Simulator option on the start-
up screen after you power-up the unit. When this screen is shown, simply press

7
USING THE 405SX
SIMULATOR OPERATION
the DOWN ARROW until “Simulator”is
highlighted. When the screen times out, the
unit will be in simulator mode.
When in simulator operation, the 405SX
responds to control inputs as if it is in actual
operation, so feel free to experiment, or to
customize the unit for your particular
operation.
To exit Simulator mode, power the unit off.
FEATURE MEMORY
If your 405SX is installed with a transducer connected, any changes you make
to the set-up or User Options (see Control Functions) while in Simulator are
retained in the unit’s memory. This allows you to use simulator to experiment
with the various set-up options, and retain your selected settings for normal
operation.
If you are using the 405SX in Simulator when no transducer is connected, any
selected options are lost when the unit is powered off. The 405SX will return
to Factory Settings, or options selected when last used with a transducer, if no
transducer is connected.
IMPORTANT: A transducer must be connected to the 405SX in
order to retain user settings selected when in simulator mode. If
no transducer is detected, the unit defaults to pre-selected
options when powered off.
What You See On-Screen
Your 405SX uses a 160 x 160 matrix FSTN LCD display. This display provides
outstanding viewability in all light conditions over a wide range of
temperatures.
At initial power-up, the 405SX uses settings that were set at the factory. After
initial use, the 405SX will remember the settings you enter.
There are several elements on-screen that are common to all modes of operation.

Temperature/Speed. The initial screen layout takes one of two basic forms
depending on whether the optional Temp/Speed accessory is installed. Figure
A shows the default view when the Temp/Speed accessory is installed. Figure B
shows the default view when the Temp/Speed accessory is not installed.
Depth. The digital depth
number shows the water depth
directly beneath the transducer
location.
Depth Range. The depth range
is shown to the right of the screen.
The upper number is 0 indicating
the surface of the water. The lower
number is one of the nine depth
ranges available that best match the
depth of the water. As the depth of
the water changes, the range
changes as necessary in order to
retain a bottom representation on-
screen. When in Auto mode,
the horizontal line at the top
of the screen is the “zero
line,”representing the surface
of the water. Occasionally
there is a gap in this line. This
gap indicates the unit is up-
dating the display even if the
bottom is not visible on-
screen, or if the bottom
information is not changing.
New sonar information appears
on the right side of the graphic
area of the display and moves
to the left as new information
is displayed. The 405SX
automatically selects the
appropriate depth range to show the depth of water beneath the transducer.
8
Bottom Depiction
USING THE 405SX
WHAT YOU SEE ON-SCREEN
Figure B
Zero Line
Figure A
Water Depth Depth Range

This range is selected so the bottom representation is typically shown about ²⁄₃
down the display.
Bottom. The graphic depiction of the bottom provides the user with an
effective tool for understanding the composition of the bottom. The FSTN type
display uses 4 discrete levels of gray to indicate the intensity of the returned
sonar signal. The 405SX can display even the smallest sonar returns with light
gray pixels. Larger returns are displayed with darker shades of gray. If the
bottom is hard and smooth, the bottom depiction is narrow and dense. If the
bottom is soft mud or sand, the depiction will be thick and less dense. This
indicates that much of the signal is absorbed by the soft bottom. If the bottom
is rocky or rugged in composition, the depiction is of varying density and
textured in appearance.
Wave action also affects the bottom depiction. The information drawn is a
distance measurement, so if the boat is moving up and down over flat bottom,
the bottom depiction often appears in regular variations that match wave
timing.
Structure. Structure is defined as any object physically attached to the bottom.
The sonar configuration of the 405SX is optimized to give the most accurate
depiction of bottom structure possible. Grass, trees, stumps, wrecks or other
debris are accurately displayed, however the depiction of these objects varies
with boat speed and direction. The
best way to learn to interpret
structure is to operate the 405SX
over a variety of known conditions
and experiment with user functions
to best represent those conditions
on-screen.
Surface Clutter. Surface clutter is
the layer of water near the surface
that is rich in algae and other
growth, and often is aerated by
wind or wave action. This area of
water interferes with sonar
transmission and often appears on-
screen as regular clusters of ind-
ividual dots near the “0”line.
9
USING THE 405SX
WHAT YOU SEE ON-SCREEN
Surface Clutter Rocky Bottom
Hard Bottom Soft Bottom

Thermoclines. Thermoclines are
sharp differences in water
temperature. These are easily
identified by the continuous
nature of the return.
Second Returns. When a sonar
signal is reflected off the bottom
back to the transducer, there is
often enough energy left in the
signal to be reflected off the
surface of the water back to the
bottom a second time. Second
returns appear as a slightly
weaker bottom representation
exactly twice the depth of the primary bottom return. The second return is most
likely to occur in shallow water and in areas of relatively hard bottom.
Fish Arches. With Fish ID off, schools of bait
fish as well as individual fish are clearly visible
on the 405SX display. Bait fish appear as
"clouds" having different shapes and sizes
depending on the number of fish and boat
speed. Individual fish appear as smaller black
and gray lines often appearing as a "fish arch."
A fish arch forms as the boat move over the fish. Due to the transducer
beam angle the distance to the fish decreases as it moves into the beam,
and then increases as it moves out. When the window graphs this distance
change, an arch appears. The true depth of the fish is the top of the arch
when the boat is directly over the fish. Boat speed and movement of the
fish greatly affect the shape of the arch. When moving slowly, a fish creates
an elongated arch. With the boat moving fast the arch appears shorter. A
partial arch forms when the fish does not move through the entire cone angle.
The 405SX displays structure such as submerged grass, brush, trees and
wrecks on the bottom. Structure can be distinguished by comparing the
area just above and below the main bottom return. Usually structure shows
as areas of dark to light gray on top of a dark bottom contour. The
appearance of structure is greatly affected by boat speed and direction; to
10
USING THE 405SX
WHAT YOU SEE ON SCREEN
Thermocline Second Return
Fish Arch Diagram

repeat the same image it is often necessary to travel the same speed and
direction over the location where the structure was originally located.
The 405SX is also capable of showing layers of water having different
temperatures. These temperature differences, called thermoclines, appear at
different depths, depending on current conditions. A thermocline typically
appears as a continuous band of light gray moving across the display at the
same depth. Thermoclines always appear above the bottom.
It is important to remember that sonar cannot distinguish between a fish
and some other object suspended in the water. Regardless of the object the
sonar detects, each will be drawn as an arch.
Fish ID. The 405SX uses
advanced signal processing
to further evaluate any
sonar return between the
surface and the bottom. For
instance, a small school of
bait fish usually appears as a
dense cluster of individual
dots. If the return meets
certain additional criteria, a
fish symbol will be assigned.
There are three different
size fish symbols used to
indicate the intensity of the
sonar return. While signal
intensity is a good indicator of relative fish size, different species of fish have
different sonar characteristics, so it is not always possible to distinguish fish size
between varying species. The signal intensity is "normalized" for depth so that
a small fish close to the boat does not appear as a large fish symbol.
ID+ adds an additional piece of information to help the user locate fish. On selected
fish symbols, the digital depth of the designated fish is drawn to help locate the fish
vertically. This is especially helpful in setting bait depths or for downrigger
operation.
11
USING THE 405SX
WHAT YOU SEE ON SCREEN
ID+ Fish Depth

CONTROL FUNCTIONS
The 405SX uses a simple six button keypad for all user input. Press any button
and an audible “chirp”confirms the control input. If a button has no function or
is inappropriate for the situation, an audible “error”is heard. The unit sounds
multiple chirps.
Power. The Power button powers the 405SX up for normal operation. When the
unit is on, POWER turns the unit off. POWER can also be used to go directly into
Simulator mode. To enter simulator, with the unit powered off, press and hold
POWER for several seconds until a continuous chirp is heard.
Light. LIGHT controls the unit’s display backlight. With the unit powered on,
press LIGHT once to turn the backlight on “low.”Press LIGHT a second time to
turn the backlight on “medium,”a third time to turn the backlight on “high”,
and a fourth time to turn the backlight off. The backlight is very effective for low-
light and nighttime operation. When the backlight is on, the 405SX will consume
more power than with the backlight off. This is important when using the 405SX
in a portable configuration powered by a separate battery, or when powering the
unit from a trolling motor battery.
When powering the unit from a battery such as in portable
applications, you can prolong the battery life by using the
backlight at a minimum.
The three lower buttons, MENU, UP ARROW and DOWN ARROW work together
to control the 405SX menu-controlled user functions.
View. VIEW selects one of several screen configurations or
“views”possible depending on the transducer in use. When using
the standard transducer, without the optional speed/temp sensor
connected, the VIEW button toggles the display between the full-
screen 2D View and the Large Digital Readout View.
The 2D View is the default view, and the view which is first seen
at power-up. Pressing VIEW again will select the Large Digital
Readout View, which increases the size of key digital information
so that it can be viewed from a great distance. Normal 2D
information is displayed on the right side of the display. Pressing
VIEW again will toggle the display back to the 2D view.
12
USING THE 405SX
CONTROL FUNCTIONS

When using the standard
transducer, with the optional
speed/temp sensor connected,
the VIEW button toggles the
display between the full-screen
2D View, the Chart View and
the Large Digital Readout View.
The Chart View, shows only the
digital depth readout, leaving
more screen area for fish
location and bottom depiction.
Menu. MENU displays a menu
on-screen for adjustment. In
normal operation, pressing
MENU repeatedly cycles
through all available menus. A
menu remains on-screen for
several seconds, and can be
adjusted by using the ARROW
keys. If no adjustment is made
in the allotted time, the menu
disappears. If you want the
menu to remain on-screen
longer press and hold MENU—
the menu will remain on-screen
indefinitely. Once you release
the menu button, the screen
will time out. Once a menu
times out, it is still considered
the active menu. Press MENU
to bring up the last menu used.
Arrow Keys. The UP ARROW
and DOWN ARROW make
adjustments to menu functions.
On the left side of every menu
there are UP ARROW and
13
USING THE 405SX
CONTROL FUNCTIONS
2D View
Large Digit View
Chart View

DOWN ARROW symbols. The symbols indicate which ARROW button has a
function in a particular situation. Either one or
both ARROW buttons can be used to adjust the
menu function. A hollow ARROW symbol means
the corresponding ARROW button has no
function. Pressing that button will result in no
adjustment and the “error”audible will be
heard. A solid ARROW symbol means the
corresponding ARROW button can be used to
affect the menu adjustment.
Abbreviated Menu. The ARROW buttons often can be
used when no menu is on-screen. In these situations,
pressing the ARROW button affects the function of the
active (last-used) menu. This is a short-cut to menu
operation. An abbreviated menu appears on-screen while
the adjustment is made and times out. A frequently used menu can be
adjusted very quickly using this technique.
After an adjustment is made to a menu function, the menu times out after a few
seconds and the unit returns to normal operation.
Menu Layout. All menus use the same basic layout. The heading at the top
describes the menu function. The UP ARROW and DOWN ARROW symbols to
the left of the menu indicate which buttons are available for adjustment. In
menus that have several possible settings, a range of adjustment indicator shows
the total range available and the current setting.
Within the menu are the options available. The selected option or current
setting is highlighted in the black box. If no adjustment is made, this is the
selected setting. Press an ARROW button while the menu is displayed to select
another option.
14
USING THE 405SX
MENU FUNCTIONS
Heading
Up Arrow Option
Down Arrow Option
Arrow Symbols
Selected Setting
Range of Adjustment Indicator
Abbreviated Menu
Menu

Several of the menus are multi-step. In some situations if an adjustment is
made, additional options become available for further adjustment. Examples of
these multi-step menus are Depth Range, Depth Alarm and Zoom. See the
detailed description of each function for further explanation.
Menu Functions
Sensitivity. The Sensitivity function controls the
sensitivity of the sonar receiver. The 405SX
automatically adjusts the level of receiver
sensitivity based on a number of factors including
the depth of the water and the level of noise
present. Noise can be caused by other electronic
devices, engines, trolling motors, propeller cavitation and hydrodynamic flow
among others. The user has the option of adjusting the Sensitivity higher or
lower based on personal preference. You can select one of 11 sensitivity
settings from -5 to +5. A setting of 0 (factory setting) has no effect on the auto-
matic sensitivity control. Increasing the sensitivity
(+1 through +5) enables the unit to display the information from progressively
smaller sonar returns. By decreasing the sensitivity (-1 through -5), the unit
effectively filters small sonar
returns.
In murky or muddy water, it is
often helpful to reduce the
sensitivity. This prevents the
display from being cluttered
with sonar returns from debris
or suspended particles. In very
clear or very deep water, it may
be helpful to increase the
sensitivity since even the
smallest sonar return may be of
interest to the user.
To adjust Sensitivity, press MENU repeatedly until the Sensitivity heading is
displayed. When the Sensitivity menu appears, use the UP ARROW to increase the
sensitivity, or the DOWN ARROW to reduce sensitivity. To sequence through the
available settings, press and hold either ARROW button. Release the button at the
setting you want to select.
15
USING THE 405SX
MENU FUNCTIONS
High Sensitivity (+) Sensitivity at “0”
Low Sensitivity (-)

After an adjustment is made, the menu
disappears and the new sensitivity setting is in
affect. If additional time is needed to study a
menu, press and hold the MENU button and
the menu will remain on-screen indefinitely. If
you need to make an additional adjustment,
press the UP ARROW or DOWN ARROW
button.
Depth Range. The Depth Range function
controls the vertical distance displayed on the
graphic area of the display. There are nine
depth ranges available. The top of the range is
always 0, or the surface of the water. Ranges
of 0–15', 0–30', 0–60', 0–120', 0–180',
0–240', 0–360', 0–480', and 0–600'. The range
that positions the bottom depiction closest to
the bottom of the screen, will best utilize the
available display resolution.
Using the factory setting of AUTO the 405SX
can automatically adjust the depth range
depending on the depth of the water. The unit
tries to maintain the bottom depiction about ²⁄₃
down the total range (for example, in 20' of
water, the 0-30' range would be
selected). This provides the best
display resolution and therefore
the best target separation
possible.
The Depth Range can be
adjusted manually. Press MENU
repeatedly until the Depth
Range menu is visible. Two
options are available: Auto and
Manual.
The manual setting enables you
to adjust the current depth
16
USING THE 405SX
MENU FUNCTIONS
Depth Range

range setting. The unit no longer adjusts the Depth Range to the most appropriate
range for bottom display. Often, the bottom may not be visible on-screen. The
digital depth readout always determines the depth of the bottom, even if it is not
visible on-screen.
Using manual Depth Range control, you can view sonar information from the area
near the surface in greater detail.
To return to automatic Depth Range control, press the MENU button until the
Depth Range menu appears on-screen and use the UP ARROW to select AUTO.
Zoom. The 405SX uses a greatly enhanced Zoom
capability called “TruZoom”which offers
expanded information on a select area of sonar
information. Zoom is similar to Depth Range
because it controls the range of information
displayed on screen. Zoom, however, allows for
selection of ranges beneath the surface so any
area of water between the surface and the bottom can be enlarged to provide
more detailed information. By using the full display to show a small area of
coverage, the effective display resolution is increased, and the unit’s ability to
separate close targets is enhanced.
The Zoom ranges available are dependent on the
current depth range. In the 15' depth range,
TruZoom displays a range equal to one half the
current depth range. In the 30', 60', 120', 180',
240', 360', 480' and 600' depth ranges,
TruZoom displays a range equal to one fourth the
current depth range. The box at the right side of
the screen outlines the area to be zoomed.
The 405SX shows Zoom range in conjunction
with the full depth range. The Zoom range is shown on the left side of the
screen and full range information is shown on the right side of the display. The
area which is being enlarged by Zoom is indicated by the square box. Zoom can
either operate automatically, in which the Zoom range is constantly adjusted to
show the bottom, or manually, in which the user controls the location of the
Zoom range.
17
USING THE 405SX
MENU FUNCTIONS

“Automatic”Zoom is especially helpful when looking
for structure or bottom detail. The “Automatic”Zoom
keeps the bottom in view even in quickly changing
terrain. “Manual”Zoom provides detailed information
of any area from the surface to the bottom.
In “Manual”Zoom, the Zoom range does not move as
the terrain changes. To operate Zoom, press MENU
repeatedly until the Zoom menu is on-screen. Three
options are available: “Off”(Factory Setting), “Auto”
(Automatic bottom tracking Zoom), and “Manual”(User
controlled Zoom range). Press the DOWN ARROW once
to highlight Auto or twice to highlight Manual. If
Manual is selected a submenu will appear allowing
manual zoom range adjustment. When the menu
disappears, full range information is displayed on the
right as always. The square box indicates the Zoom
range. In Auto Zoom, the box will move vertically to
remain in the general area of
the bottom return. The left
side of the screen is a
magnified view of the
information seen inside the
Zoom range box. The upper
and lower depth limits of the
Zoom range are shown on the
right side of the Zoom view.
Note: It is not possible to
use Zoom in conjunction
with the Large Digital
View.
To disable Zoom, press the MENU button until the Zoom menu is on-screen. Use
the UP ARROW to highlight Off, and let the menu time out.
When the unit is powered off, the Zoom menu returns to Zoom Off.
18
USING THE 405SX
MENU FUNCTIONS
Upper Zoom Limit
Lower Zoom Limit