Humminbird 300TX User manual

INSTALLATION PREPARATION
PARTS SUPPLIED
PARTS SUPPLIED
Before installing your new Humminbird fishfinder, please ensure the following parts are
included in the box:
•Fishfinder
•Transducer with 20’ (6m) of cable and mounting hardware kit
•Mounting system and mounting hardware kit
•6’ (2m) power cable
•Publications kit
It any of these items is missing, call our Customer Support Hotline.
ACCESSORIES
Humminbird offers a wide assortment of accessories that complement and expand the
capability of your new fishfinder. These accessories are designed with the same high
standards and are backed by the same one-year warranty. 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 or factory direct through our number listed in the Customer
Support section.
INSTALLATION OVERVIEW
Your Humminbird fishfinder 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.
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 waterflow-usually on
the transom ofthe boat. There are several mounting options for the transducer. Review
the following section to determine the method that works for you and your boat.

INSTALLATION PREPARATION
INSTALLATION OVERVIEW
Determining How to Mount the Transducer
Your Humminbird fishfinder includes a standard
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 installations require no holes be drilled into the
boat and through experimentation, high-speed operation
comparable to transom mounting can be achieved. Two-part slow cure epoxy (not
included) is required to glue the transducer in place.

INSTALLATION PREPARATION
ALTERNATE MOUNTING METHODS
ALTERNATE TRANSDUCERS AND MOUNTING METHODS
Your Humminbird fishfinder 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 with a portable mounting kit available from
Humminbird. 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 a different accessory kit. This
accessory includes a bracket and hose clamp that allows
mounting the transducer to the body of most trolling motors.
Thru-Hull Mounting
Thru-hull transducers install through a hole drilled in the hull
of the boat. Larger boats or boats with inboard motors create
turbulence that make transom mounting ineffective. Also,
hulls that are very thick or are double layered, or made from
materials such as wood or metal, (which do not conduct
sonar signals) make inside the hull mounting inadvisable.
Thru-hull mounting may require the use of a fairing block to level the transducer with the
waterline. Also, since special tools and knowledge may be required to perform this type
of installation, it is best to refer to a qualified marine technician.

INSTALLATION PREPARATION
TRANSDUCER EXCHANGE
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 cost. Refer
to the Accessory catalog or call Customer Support for information.
BEGINNING INSTALLATION
Now that you have determined the transducer mounting method you can begin
installation of your new Humminbird fishfinder. The installation guide included on the
next few pages 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 included with your manual.
In addition to the parts included you need the following for installation and operation:
•A powered hand drill and various drill bits
•Philips and flat-head screwdrivers
•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
TRANSOM INSTALLATION
Do not begin this transducer installation until you read the Installation
Preparation in the Operation Guide. This chapter contains information critical to
the correct installation of your transducer.
Due to the wide variety of boat hulls, only general instructions are presented in
the installation guide. Each boat hull represents a unique set of requirements that
should be evaluated prior to installation.
TRANSOM INSTALLATION
Step One -Determine Where to Mount the Transducer
Begin the transducer installation by determining where on the
transom to install the transducer. Consider the following to find
the best location:
•It is very important to locate the transducer in an area which is
relatively free of turbulent water, As aboat moves through the
water, turbulence is generated by the weight of the boat, and
the thrust of the propeller(s). This turbulent water is normally
confined to areas immediately aft of ribs, strakes or rows of
rivets on the bottom of the boat, and in the immediate area of
the propeller(s) (Figure 1). On outboard or inboard/outboard
boats it is best to stay at least 15” (40cm) to the side of the
propeller(s).
•If possible, viewing the transom of the boat while the boat is
moving will provide the best means of locating turbulence free
water. If maximum high-speed operation is a high priority, this
is the recommended method. If this is not possible, select a
location on the transom where the hull forward of this location
is smooth, flat, and free of protrusions or ribs.
•The transducer when mounted should point straight down.
The design of the transducer will accommodate a wide range
of deadrises and remain ported straight down (Figure 2).
•On boats with stepped hulls, it may be possible to mount the transducer on the step.
Never mount the transducer on the transom behind a step, as this area of the
transom will not be in contact with the water at high speed (Figure 3).

INSTALLATION
TRANSOM INSTALLATION
•If the propeller(s) is (are) forward of the transom, itmay be impossible to find an
area clear from turbulence, and a different mounting technique or transducer type
should be considered.
Step Two -Drill the Mounting Holes
1. Remove the mounting template from the front of the Operations Manual.
2. Hold the template on the transom of the boat in the location where the transducer
will be installed (Figure 4). Align the template vertically, ensuring the lower edge of
the transom meets with the bottom corner of the template.
3. Using a pencil or punch, mark the two mounting holes
shown on the template onto the transom. Do not mark or
drill any other holes at this time.
4. Using a 5/32” (4mm) bit drill the two holes to a depth of
approximately 1" (3cm). On fiberglass hulls, it is best to
start with a smaller bit and useprogressively larger drill bits
to reduce the chance of chipping or flaking the outer
coating.
Step Three -Assemble the Transducer
1. Attach the Pivot to the transducer body as shown in Figure
5, using the #8–3/8” (9mm) long allen headed pivot screw,
the headed pin, the two flat washers, and the two toothed
lock washers.
Note: The toothed lock washers must be positioned
between the transducer and the pivot ears. The flat
washers must be positioned to the outside at the pivot
ears.
2. Using the AIlen wrenches provided, loosely tighten the pivot
screw (Figure 6). Do not completely tighten the assembly at
this time, so the pivot angle can be adjusted later.
3. Insert the pivot/transducer assembly into the mounting
bracket as shown in Figure 7. Do not snap the assembly
closed.

INSTALLATION
TRANSOM INSTALLATION
Step Four -Mount the Transducer to the Transom
1. Apply silicone sealant to the mounting holes drilled into the transom.
2. Align the transducer assembly with the drilled holes in the transom (Figure 8).
3. Use either a flat head screwdriver, a 5/16" (8mm) hex driver, or a 5/16" (8mm)
socket to mount the assembly. Using the two #10–1”
(25mm) long slotted hex head screws, mount the transducer
assembly to the transom as shown. Do not fully tighten the
mounting screws in order to vertically adjust the transducer.
Snap the pivot down into place.
Step Five -Adjust the Running Position of the Transducer
The bracket allows height and tilt adjustment, the pivot screws
allow angular adjustment. Initially, adjust the transducer as
described in the following paragraphs. Further adjustment may
be necessary to refine the instillation after high speed testing.
1. First adjust the pivot angle of the transducer body so its
length is parallel with the length of hull of the boat. Then
pivot the transducer down so the rear is about 1/4 inch
(6mm) lower than the front (Figure 9).
2. Fully tighten the two pivot screws using the Allen wrenches.
It may be necessary to retighten the pivot screws after the
initial use as the plastics may still be seating to the lock
washers.
3. Adjust the height of the assembly so the face of the
transducer is 3/16" (4.5mm) beneath the lower edge of the
transom (Figure 10). Mark the position of the mounting
bracket on the transom with a pencil.
4. Force the pivot to the up position to gain access to the
mounting screws. Assure the transducer location has not
changed, then fully tighten the two mounting screws (Figure
11). Snap the pivot back down.
Confirm the pivot angle has not changed.
Note: A third screw location is provided for the
mounting bracket. Drill this hole and install the screw after final testing and
adjustments have been completed.

INSTALLATION
TRANSOM INSTALLATION
Step Six -Route the Cable
There are several ways to route the transducer cable to the to the area where the
control head will be installed. The most common procedure routes the cable through the
transom into the boat.
Inside the boat there is often a channel or conduit used for other
wiring that the cable can be routed along. Do not cut or shorten
the transducer cable and try not to damage the cable insulation.
Route the cable as far as practical from the VHF radio antenna
cables or tachometer cable to reduce the possibility of
interference.
If the cable is too short, extension cables are available to extend
the transducer cable up to a total of 50' (15 m). Call Humminbird
Customer Support for more information.
Follow these steps to route the cable through the transom:
1. Drill a 5/8” (16mm) hole above the water line. Route the
cable through the hole.
2. Fill the hole with silicone sealant.
3. Place the escutcheon plate over the hole and attach with the two #8 x 5/8” (16mm)
screws.
4. Secure the cable by attaching the cable camp to the transom using a #8 x 5/8”
(16mm) screw.
Note: The transducer will pivot up to 90 degrees in the bracket. Allow enough
slack in the cable for this movement. It is best to route the cable to the side of the
transducer so the cable will not be damaged by the transducer during movement.

INSTALLATION
INSIDE THE HULL INSTALLATION
INSIDE THE HULL INSTALLATION
Inside the hull installation requires the mount system and control
head be installed and operational. See Installing the Control Head
for instruction on installing the unit.
Inside the hull mounting generally produces good results in single
thickness fiberglass-hulled boats. Humminbird cannot guarantee
depth performance when transmitting and receiving through the
hull of the boat since some signal loss occurs. The amount of loss
depends on hull construction and thickness, and the installation.
This installation requires slow-cure two-part epoxy. Do not use
silicone or any other soft adhesive to install the transducer, as this
material reduces the sensitivity of the unit. Five minute epoxy has
a tendency to cure before all the air bubbles can be purged.
Step One -Determine the Mounting Location
Begin the transducer installation by determining where inside the
hull to install the transducer. Consider the following to find the
best location:
•Observe the outside of the boat hull to find the areas that are
mostly free from turbulent water. Avoid ribs, strakes, and other
protrusions as these create turbulence (Figure 14).
•As a general rule, the faster the boat can travel the further aft
and closer to the centerline of the hull the transducer has to be
located to remain in contact with the water at high speeds.
Step Two -Test the Mounting Location
There is no opportunity for adjustment after the transducer glued in place. Therefore, it
is best to perform a trial installation on inside the hull transducers first, and run the boat
at high speeds to determine the best mounting area.
1. At the identified mounting location, lay the transducer body face down with the
pointed end towards the bow.
2. Fill the hull with enough water to submerge the transducer body. Use a sand filled
bag or other heavy object to hold the transducer in position.
The transducer cannot transmit through air. The water purges any air from between
the transducer and the hull and fills any voids in the coarse fiberglass surface.

INSTALLATION
INSIDE THE HULL INSTALLATION
3. Power up the Control Head.
4. Run the boat at various speeds and water depths while observing the screen on the
Control Head. If the unit functions well at low speeds but begins to skip or miss the
bottom at higher speeds, the transducer needs to be moved. If depth performance is
required, test the fishfinder in water at the desired depth. Test different locations in
the hull until the optimum performance is achieved.
Step Three -Permanently Mount the Transducer
1. Once the mounting location is determined, mark the position of the transducer.
2. Remove the water from inside the hull and thoroughly dry the
mounting surface. If the surface is excessively rough, it may be
necessary to sand the area to provide a smooth mounting
surface.
Ensure the mounting area is clear and dry.
3. Mix an ample quantity of two-part slow-cure epoxy slowly and
thoroughly. Avoid trapping air bubbles.
4. Coat the face of the transducer and the inside of the hull (Figure
16).
5. Press the transducer into place with a slight twisting motion to
purge any trapped air from underneath, keeping the pointed end
of the transducer body pointed forward (Figure 17).
Note: Proper operation requires the pointed end of the
transducer body to face towards the bow.
6. Weight the transducer so it does not move while the epoxy is curing.
When the epoxy cures, no water is necessary inside the hull. Neither water, spilled
gasoline, or oil will affect the performance of the transducer.

INSTALLATION
CONTROL HEAD INSTALLATION
CONTROL HEAD INSTALLATION
Step One -Determine Where to Mount
Begin the installation by determining where to mount the control head. Consider the
following to determine best location:
•The cables for power, transducer and temp/speed accessories (if applicable) should
be installed first and must reach the mounting location. Extension cables are
available.
•There are two ways to route the cables to the unit: through a
hole in the mounting surface underneath the mounting bracket
or from a hole outside the mounting bracket. Routing the cables
down under the mount provides maximum weather protection;
however this is not always feasible if the area under the
fishfinder is inaccessible. In this case, route the cables through
a hole at another location and cover with the supplied hole
cover.
•The mounting surface should be adequately supported to
protect the fishfinder from excessive wave shock and vibration,
and provide visibility while in operation.
•The mounting area should allow sufficient room for the unit to
pivot and swivel freely, and for easy removal and installation
(Figures 18-19).
Step Two -Connect the Power Cable to the Boat
A 6’ (2m) long power cable is included to supply power to the
fishfinder. You may shorten or lengthen the cable using 18 gauge
multi-stranded copper wire.
CAUTION: Some boats have 24 or 36 volt electric systems. Be
sure your unit is connected to a 12 VDC power supply.
The Power can be connected to the boat's electrical system at two
places: a fuse panel, usually located near the console, or directly to the battery.
If a fuse terminal is available, use crimp-on type electrical connectors (not included) that
match the terminal on the fuse panel. Attach the black wire to ground, andthe red wire
to 12 VDC power (Figure 20). Be sure to use a one amp fuse in the connection. If you
must wire the control head directly to a battery, be sure to install an inline fuse holder

INSTALLATION
CONTROL HEAD INSTALLATION
and one amp fuse (not included) for the protection of the unit (Figure 21). Humminbird is
not responsible for over voltage or over current failures.
In order to minimize the potential for interference with other
marine electronics a separate power source (such as a
second battery) may be necessary.
Step Three -Drill the Mounting Holes
1. Set the mounting bracket in place on the mounting
surface. Mark the four mounting screw locations with a
pencil or punch.
2. Set the mounting bracket aside, and drill the four
mounting screw holes using a 9/64” (3.6mm) bit.
Step Four -Run the Cables
1. If the cables must pass through a hole underneath the
mounting surface, mark and drill a 1” (25mm) hole
centered between the four mounting holes (Figure 22).
Note: if the cables must pass through the mounting
surface at a different location, drill the 1" (25mm) hole at
that location and pass the cables through from
underneath. Also, you must break out the tabs on the
rear of the mounting base using needle nose pliers
(Figures 24-25).
2. Insert all cables through the 1” (25mm) hole from beneath
the mounting surface.
3. Pass the cables through the grommet (if the cable hole is
underneath the mounting bracket) then press the grommet
in place around the cables and into the 1” (25mm) hole.
4. Pass the cables through the mounting base, out the top of the mounting bracket.
5. Place the mounting bracket on the mounting surface aligned with the drilled holes.
Insert the four flathead wood screws into the mounting holes and tighten fully (Figure
23).
Optional: If the cables pass outside the mounting bracket, install the hole cover
over the hole and fasten in place using the two #8 x 7/8” (22mm) wood screws
(Figure 24).

INSTALLATION
CONTROL HEAD INSTALLATION
Step Five -Assembling the Connector Holder
1. Insert the cable connectors into the connector holder.
The cable connectors are labeled, and there are
corresponding labels on the connector holder (Figure
26). The slots for the connectors are keyed to prevent
reverse installation, so do not force the connector into
the holder.
2. Carefully pull the excess cable from beneath the-
mounting surface so the connector holder aligns with the
mounting holes on the front of the mounting bracket
(Figure 27).
3. Snap the support plate to the rear of the connector
holder (Figure 28).
4. Insert the connector holder into place and use the two
#6-32 x ¾” (9mm) screws to fasten it to the mounting
bracket (Figure 28).
5. Install the control head by sliding it onto the mounting
bracket until it is fully seated. To remove the unit simply
depress the latch on the rear of the unit and lift (Figure
29).
Your Humminbird is now ready for operation.

INSTALLATION
TEST THE INSTALLATION
TEST THE INSTALLATION
Testing should be performed with the boat in the water, however you can initially
confirm basic operation with the boat trailered.
Press POWER once to turn the unit on. There will be an audible chirp when any button
is pressed to confirm the button press. If the unit does not power-up, ensure the unit is
fully seated on the mount and that power is available.
The first screen provides four options: Start-up, Options, Simulator, and Diagnostic. A
message at the bottom of the screen indicates the transducer connection. If no
transducer is detected (or one is not connected), the message will indicate this and the
unit will go into simulator after the initial screen times out.
Note: the transducer must be submerged in water for reliable transducer
detection.
If a transducer is detected, the unit will enter “Start Up” or normal operation unless you
choose another option. If you do not press any button before the timer reaches “0”, the
normal operation screen is displayed. If the boat is in water, sonar data appears.
If the bottom is visible on screen with a digital depth readout, the unit is working
properly. Ensure the boat is in water greater than 2’ but less than the depth
capability of the unit and the transducer is fully submerged. Remember the sonar signal
cannot pass through air.
If the unit is working properly gradually increase the boat speed to test high-speed
performance. If the unit-functions well at low speeds but begins to skip or miss the
bottom at higher speeds, the transducer requires adjustment. Refer to the appropriate
transducer installation section for more detail.
Note: it is often necessary to make several incremental transducer adjustments
before optimum high-speed performance is achieved.
Important: For Transom Mount transducer installations, install the third mounting screw
after the final transducer adjustments.
Humminbird •3 Humminbird Lane•Eufaula, Alabama 36027

Using the 300TX
Actual depth capability depends on factors such as bottom hardness, water conditions,
and transducer installation. Units will typically read to deeper depths in freshwater than
in salt water.
Simulator Operation
The 300TX 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 300TX.
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 the
DOWN ARROW until “Simulator” is highlighted. When the screen times out, the unit will
be in simulator mode. When the screen times out, the unit will be in simulator mode.
When in simulator operation, the 300TX 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.
When in simulator mode, the word “simulator” occasionally scrolls across the
display indicating the information on-screen is not real sonar data.
Feature Memory
If your 300TX 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 300TX in Simulator when no transducer is connected, any selected
options are lost when the unit is powered off. The 300TX 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 300TX 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 300TX uses a 128 x 64 matrix FSTN LCD display. This
display provides outstanding viewability in all light conditions
over a wide range of temperatures.
At initial power-up, the 300TX uses settings that were set in the
factory. After initial use, the 300TX 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 oneof two basic forms depending
on whether the optional 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 updating 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 tothe left as new information is
displayed. The 300TX automatically selects the appropriate
depth range to show the depth of water beneath the
transducer. 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 an effective tool for
understanding the composition of the bottom. 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 tothe bottom. The
sonar configuration of the 300TX 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 boatspeed and direction.
The best way to learn to interpret structure is to operate the 300TX 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
individual dots near the “0” line.
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 ID. The 300TX 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 ofrelative fish size, the 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 operations.
The specific fish symbol indicates the type of sonar beam
the fish is detected in. This gives you a reliable indicator of
side to side location relative to boat movement. Fish
symbols which are hollow are detected in the outside two
beams. Hollow fish symbols facing to the left are detected
in the left beam, and thus the fish is to the left side of the
boat. Solid fish symbols represent fish in the single center beam, and these fish are
directly under the boat.
Control Functions
The 300 TX uses a simple, five-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, and audible “error” is heard. The unit sounds multiple
chirps.
Power. The Power button powers the 300 TX 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 ”high.” Press LIGHT a
second time to turn the backlight on “Low,” and a third time turns the
backlight off. The backlight is very effective for low-light and nighttime operation. When
the backlight is on, the 300TX will consume more power than the backlight off. This is
important when using the 300TX 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 batter life by using the backlight at a minimum.
The three lower buttons, MENU, UP ARROW, and DOWN ARROW work together to
control the 300TX menu-controlled user functions.
Menu. MENU displays a menu on-screen for adjustment. In normal operation,
pressing MENU repeatedly cycles through all available menu headings. When a menu
heading displays, the full menu appears after a short pause. A menu remains in-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. 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 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 button can be used to affect the menu adjustment.
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. The 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.
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
300TX 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 devises, 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 automatic sensitivity control. Increasing the
sensitivity (+1 through +5) enables the unit to display the information from progressively
smaller sonar returns. By decreasing the sensitivity bias (-1 through –5), the unit
effectively filters small sonar returns.