Garmin GMR 40, GMR 20 User Manual

GMR 20/40

Marine Radar

Owner’s Manual

© Copyright 2005 Garmin Ltd. or its subsidiaries

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INTRODUCTION > ABOUT THIS MANUAL

INTRODUCTION

Terminology used Throughout this Manual

• This manual refers to the radome hardware as the “scanner,”

About This Manual

Congratulations, and thank you for choosing Garmin’s GMR 20/40
Marine Radar. The addition of the GMR 20/40 Marine Radar to your
Garmin Marine Network, enhances the capability of your system by
adding graphical radar data to your Garmin Marine Network.

This manual covers the features and operation of the GMR 20/40
Marine Radar when viewed on the Garmin Marine Network
Chartplotters. To get the most out of your new radar, take time to read
this manual and learn the operating procedures for your unit in detail.

Introduction:

manual and the Table of Contents.

Main Pages: The Main Pages contain information on the setup and
operation of the GMR 20/40.

Appendix: The Appendix contains information such as specifications,
and license requirements. You can also find warranty and FCC
information in the Appendix.

Index: Use the Index as a key word search to help you find
information more quickly.

The introduction contains information about this

• This manual uses the term “chartplotter” when referring to a

• This manual uses the term “Radar Page.” The Radar page is

• This manual uses the term “

“Radar,” or “GMR 20/40.” These terms can be used
interchangeably.

Garmin GPSMAP 3000 series Multi Function Display.

a dedicated page on the Garmin chartplotter showing radar
information. Radar information can be displayed as a split
screen on any of the chartplotter main pages.

highlight” when referring to the on­screen cursor. To highlight something, use the Arrow Keypad
on the chartplotter to move the cursor to the desired item. The
on-screen cursor is represented by changing the color of the
highlighted box to yellow.

GMR 20/40 Owner’s Manual i

INTRODUCTION > TABLE OF CONTENTS

Introduction ...........................................................................i

About This Manual ................................................................... i

Terminology used Throughout this Manual ........................... i

GMR 20/40 Operation ..........................................................1

Radar Overview ....................................................................... 1

The Radar Page ....................................................................... 1

Radar Page Layout .......................................................................... 3

Range Rings .............................................................................. 4

Heading Line ............................................................................. 4

Digital Navigation Data ............................................................ 4

The Radar Configuration Page ............................................... 5

The Radar Adjustment Menu .................................................. 5

Gain ................................................................................................ 6

Sea Clutter ......................................................................................6

Rain Clutter ..................................................................................... 7

FTC (Fast Time Constant) .............................................................. 7

Zoom ............................................................................................... 8

Target Expansion ............................................................................8

Trails ............................................................................................... 9

Guard Zone ..................................................................................... 9

VRM/EBL ..................................................................................... 10

MARPA ......................................................................................... 11

MARPA Setup .............................................................................12

Hide/Show Navigation Features ................................................... 13

Additional Adjustment Menu Items ............................................. 13

Map Cursor On/Off ....................................................................... 14

Setup ............................................................................................. 14

The General Tab ...................................................................... 14

The Display Tab ...................................................................... 15

The MARPA Tab ..................................................................... 16

The Advanced Tab ..................................................................16

Enter Standby/Begin Transmitting ............................................... 17

Map Page Radar Overlay ...................................................... 17

Appendix ............................................................................19

European License Requirements ........................................ 19

Specifications ........................................................................ 20

FCC Compliance .................................................................... 21

Software License Agreement ............................................... 22

LIMITED WARRANTY ............................................................ 22

Warning and Cautions .......................................................... 24

ii GMR 20/40 Owner’s Manual

GMR 20/40 OPERATION > RADAR OVERVIEW—THE RADAR PAGE

GMR 20/40 OPERATION

When the new radar is detected, the chartplotter automatically adds
a dedicated Radar page to the page list. If the Radar page is not

Radar Overview

The Garmin GMR 20/40 Radar Scanner transmits a narrow beam of
microwave energy in a rotating 360° pattern. When the transmitted

available, press and hold the ADJ/MENU key until the Main Menu is
displayed. Using the ARROW KEYPAD, highlight the System tab,
and select Radar from the Services list at the bottom of the page.

energy contacts a target, some of that energy is reflected and returned
to the scanner. The scanner collects the returned energy for processing
and display. The GMR 20/40 is operated and adjusted using the
controls on your Gamin chartplotter. Radar data is presented on a
dedicated Radar page, or as an overlay on the Map page. All radar
controls are accessible on both pages.

To Select the Radar page for display:

1. Press the PAGE key to display the Pages list.

2. Using the ARROW KEYPAD, select Radar.

3. Press the ENTER key.

The Radar Page

With the GMR 20/40 Radar properly installed, at power up, the
Garmin chartplotter should detect the GMR 20/40 as a new network
connection.

Note: A software update may be needed for the GMR 20/40
to function properly. If the message “Incompatible Software
Version” is displayed when the chartplotter is powered on, the
software in the chartplotter needs to be updated. A software
update card is provided with the GMR 20/40.

Pages List

GMR 20/40 Owner’s Manual 1

GMR 20/40 OPERATION >THE RADAR PAGE

In the Status Bar at the top of the Radar page, the message “Radar
Warming Up” is displayed with a countdown to Standby Mode. The
countdown to Standby Mode is also displayed in the middle of the
radar display. When the countdown reaches zero, the message “Hold
FCTN to transmit” is displayed.

As a safety feature, the scanner enters Standby Mode after it is
warmed up. This provides the operator an opportunity to verify
that the area around the scanner is clear before beginning radar
transmission. It is important to remember that the microwave energy
transmitted by the scanner can potentially be dangerous.

When the area surrounding the scanner is clear, press and hold the
FCTN key. The message “Do you want to begin radar transmission?”
is displayed. Select Yes, then press the ENTER key. Before
transmission begins, the message “Spinning Up” is displayed while
the radar antenna reaches nominal rotation speed. When the message
disappears, the radar begins painting an image.

Caution: The GMR 20/40 Radar transmits microwave energy that
has the potential to be harmful to humans and animals. Before
beginning radar transmission, verify that the area around the
scanner is clear. The GMR 20/40 transmits a beam approximately
12° above and below a line extending horizontally from the center
of the scanner. Avoid looking directly at the scanner as the eyes
are the most susceptible part of the body.

2 GMR 20/40 Owner’s Manual

GMR 20/40 OPERATION > RADAR PAGE LAYOUT

Radar Page Layout

This section describes the features of the Radar page and how its features are displayed. By default, the Radar page displays a Status Bar along
the top, user configurable Digital Navigation Data down the right side, a Heading Line, and Range Rings. Soft Key options that allow the user
to quickly access functions and change settings may be displayed along the bottom of the page.

Status Bar

Range Rings

Heading Line

Zoom Scale

Ring Separation

GMR 20/40 Owner’s Manual 3

GMR 20/40 Owner’s Manual 3

Digital

Navigation

Data

Soft Key Options

GMR 20/40 OPERATION > RANGE RINGS—HEADING LINE—DIGITAL NAVIGATION DATA

Range Rings

The Range Rings are used as an aid to quickly determine distance to
a target. In the lower right corner of the display are two scales. The

Heading Line

The Heading Line is shown from your current position along the path

of your current heading.
upper scale is the current zoom scale. This scale is changed using the
RANGE keys. The Zoom Scale is represented by the Range Ring
with tick marks around the circumference. The tick marks are arrange
with a minor tick marks every five degrees and major tick marks
at thirty-degree increments. These tick marks can aid in quickly
determining the azimuth to a target. The lower scale represents the

Digital Navigation Data

By default, the Radar page shows one column of digital navigation

data with four data fields. The Radar page can be configured to show

two columns of data with up to seven data fields each. Each data field

can be configured to show a variety of data.

distance between the Range Rings.

3/4 nm

1/2 nm

1/4 nm

4 GMR 20/40 Owner’s Manual

GMR 20/40 OPERATION > THE RADAR CONFIGURATION PAGE—THE RADAR ADJUSTMENT MENU

The Radar Configuration Page

The Radar Configuration page is used to change the look of the Radar
page. Please refer to the GPSMAP 3000 series Owner’s Manual for
information on “Configuring the Main Pages.”

To display the Radar Configuration page:

Press and hold the DATA\CONFIG key.

The Radar Adjustment Menu

The Radar Adjustment Menu is a numbered list of options that allow

direct access to the settings and features most commonly used on the

Radar Page. There are several adjustment options available: Gain, Sea

Clutter, Rain Clutter, FTC, Zoom, Target Expansion, Trails, Guard

Zone, VRM/EBL, MARPA, and Hide/Show Navigation Features. All

adjustments are made using the Arrow Keypad, or Data Entry Keys.

Radar Configuration Page

Radar Adjustment Menu

GMR 20/40 Owner’s Manual 5

GMR 20/40 Owner’s Manual 5

GMR 20/40 OPERATION > THE RADAR ADJUSTMENT MENU

continued

To change a Radar Adjustment Menu setting:

1. Press the ADJ key to display the Adjustment Menu.

2. Using the ARROW KEYPAD or DATA ENTRY keys, select
an option. If using the ARROW KEYPAD to highlight an
option, press the ENTER key to display the adjustment for that
selection.

3. Using the ARROW KEYPAD, make the desired change, then
press the ENTER key to accept the change.

Gain

Selecting Gain, displays the Gain Adjustment Slider. When Auto

To return the Gain setting to Auto, move the slider to the Auto
position, or press the Auto Soft Key.

Sea Clutter

Sea Clutter is screen clutter caused by choppy sea conditions.
Adjusting the Sea Clutter setting can help eliminate the screen clutter.
Selecting Sea Clutter displays the Sea Clutter Adjustment Slider. The
slider has three preset positions: Calm, Moderate, and Rough.

is selected, the Scanner Gain is automatically adjusted to provide
optimal performance.

To change the Gain setting:

1, Using the ARROW KEYPAD, move the slider up or down.

2. Press the ENTER key to accept the change.

6 GMR 20/40 Owner’s Manual

GMR 20/40 OPERATION > THE RADAR ADJUSTMENT MENU

To change the Sea Clutter setting:

1. Using the ARROW KEYPAD, move the slider to a preset or
other position.

2. Press the ENTER key to accept the change.

The preset positions can also be selected using the Soft Key options.

Rain Clutter

Rain Clutter is screen clutter caused by rain. Adjusting the Rain
Clutter setting can help remove screen clutter caused by rain at close

FTC (Fast Time Constant)

Adjusting the Fast Time Constant can help eliminate distant screen
clutter caused by rain. The Fast Time Constant has four presets: Off,
Low, Medium, and High.

To change the FTC setting:

1. Using the ARROW KEYPAD, highlight the desired setting.

2. Press the ENTER key to accept the change.

The FTC settings can also be selected using the Soft Key options.

ranges. Selecting Rain Clutter displays the Rain Clutter Adjustment
Slider.

To change the Rain Clutter setting:

1. Using the ARROW KEYPAD, move the slider to the desired
setting.

2. Press the ENTER key to accept the change.

FTC Menu

GMR 20/40 Owner’s Manual 7

GMR 20/40 OPERATION > THE RADAR ADJUSTMENT MENU

Zoom

When a Zoom level is selected, a box showing a zoomed portion
of the screen is displayed. When Move is selected, the ARROW
KEYPAD can be used to move the box around the screen. The Zoom
setting has four presets: Off, 2x, 4x, and Move.

Target Expansion

Target Expansion increases the size of a target. Target Expansion has
two settings, On and Off. The Target Expansion setting has no effect
at range settings of 4 nm or greater.

To turn Target Expansion On/Off:

To change the Zoom setting:

1. Using the ARROW KEYPAD, highlight the desired setting.

2. Press the ENTER key to accept the change.

The Zoom settings can also be selected using the Soft Key options

1. Using the ARROW KEYPAD, highlight the desired setting.

2. Press the ENTER key to accept the change.

Target Expansion - Off Target Expansion - On

Zoom Areas

8 GMR 20/40 Owner’s Manual

GMR 20/40 OPERATION > THE RADAR ADJUSTMENT MENU

Trails

Trails are history trails that show movement of a target. When Trails
is On, all returns on the display leave a history trail. The Trails setting
determines the length of the trail. The Trails setting has four presets:
Off, Short, Medium, and Long.

To change the Trails setting:

1. Using the ARROW KEYPAD, highlight the desired setting.

2. Press the ENTER key to accept the change.

Trails - Off Trails - On (medium)

To clear the Trails, select Clear Trails on the Adjustment Menu or
press the Clear Trails Soft Key.

Guard Zone

A Guard Zone is a user defined area of protection. If a target enters
the defined Guard Zone, an alarm is sounded. Two Guard Zones can
be defined at any given time.

The Guard Zone Menu has two areas, “Guard Zone 1” and “Guard
Zone 2.” Each area has two settings, a setting to Show/Hide the
Guard Zone, and Adjust.

Guard Zone

continued

GMR 20/40 Owner’s Manual 9

GMR 20/40 OPERATION > THE RADAR ADJUSTMENT MENU

To Define a Guard Zone:

1. Using the ARROW KEYPAD, highlight Show Guard Zone 1/2
and press the ENTER key.

2. Using the ARROW KEYPAD, highlight Adjust and press the
ENTER key.

3. Using the ARROW KEYPAD, define the desired area on the
Radar page.

4. Press the ENTER key to accept the change.

With a Guard Zone selected on the Radar page, Soft Key options may
be available.

The diameter of the VRM and the angle of the EBL are adjustable.

To adjust the VRM/EBL:

1. Using the ARROW KEYPAD, highlight Adjust and press the

2. Press the ARROW KEYPAD right/left to rotate the Electronic

3. Press the ARROW KEYPAD up/down to increase/decrease

4. Press the ENTER key to accept the changes.

VRM/EBL

The VRM (Variable Range Marker) and EBL (Electronic Bearing
Line) tools measure range and bearing to a target. The center point
of the VRM can be moved, allowing measurement from one target to
another. Two V/E tools can be activated at the same time.

The VRM/EBL Menu has two areas, “VRM/EBL 1” and “VRM/EBL

2.” Each area has two settings, a setting to Show/Hide the VRM/EBL
and Adjust.

To activate VRM/EBL 1 or 2:

Using the ARROW KEYPAD, highlight Show VRM/EBL 1/2

and press the ENTER key.

ENTER key.

Bearing Line around the center point of the VRM.

the size of the Variable Range Marker.

Variable Range Marker

(VRM)

Electronic Bearing Line

(EBL)

10 GMR 20/40 Owner’s Manual

GMR 20/40 OPERATION > THE RADAR ADJUSTMENT MENU

To move the center location of the VRM:

1. Using the ARROW KEYPAD, highlight Move and press the
ENTER key.

2. Using the ARROW KEYPAD, move the center point of the
VRM to the desired location.

3. Press the ENTER key to set the new location.

Acquiring Target

Target is Safe

To use the VRM/EBL, expand the diameter of the VRM so that the
outer edge touches the target. Rotate the EBL until it intersects the

Target is Dangerous

VRM at the target location. The measured range and bearing are
displayed in the lower left corner of the screen.

MARPA

Lost Target

The Mini Automatic Radar Plotting Aid or MARPA function is used
to aid in collision avoidance. MARPA can track up to ten designated
targets. Detailed information including Bearing, Range, Course,
Speed, Closest Point of Approach, and Time to Closest Point of
Approach for each target is displayed in the MARPA list.

Note: The MARPA function requires the use of a heading sensor.
The heading sensor must output the NMEA sentence HDM or
HDG at format 0183, v2.30 or higher.

MARPA relies on a Heading Sensor to provide accurate own vessel
heading information. Accurate heading data enhances MARPA’s
performance. Each target being tracked by MARPA is represented by
a symbol. The symbols indicate the current state of the target.

GMR 20/40 Owner’s Manual 11

For each target, a number and Vector Line is displayed with the
symbol. The number is the MARPA List ID Number. The Vector Line
is a visual reference of the target’s course and speed.

To designate a MARPA target:

1. Using the ARROW KEYPAD, highlight Acquire Target and
press the ENTER key.

2. On the Radar page, using the ARROW KEYPAD, move the
pointer to the desired target and press the ENTER key.

continued

GMR 20/40 OPERATION > THE RADAR ADJUSTMENT MENU

While a target is being designated, a box is placed around the target.
When MARPA begins tracking the target, the box is replaced with the
appropriate symbol.

Acquiring Target

Tracking Target

To display the MARPA List:

Using the ARROW KEYPAD, highlight MARPA List and press

the ENTER key.

MARPA List

MARPA Setup

The MARPA Setup Menu contains settings for Vector Length, Target
History, Own Vessel Safe Zone, Tine To Safe Zone, Safe Ring Zone,
and Velocity Reference.

To display the MARPA Setup Menu:

Using the ARROW KEYPAD, highlight MARPA Setup and

press the ENTER key.

12 GMR 20/40 Owner’s

GMR 20/40 OPERATION > THE RADAR ADJUSTMENT MENU

Own Vessel Safe Zone—is a circular area defined by a range setting
that is centered on your own vessel. If a target enters the defined area
an alarm is sounded. The Safe Zone can be set to a distance between
.01 and 2 nautical miles.

Time To Safe Zone—sounds an alarm if MARPA determines that a
target will intersect the Own Vessel Safe Zone within the defined time
interval. The time interval settings range from 3 to 24 minutes.

Safe Zone Ring—displays a ring on the Radar page depicting the
Own Vessel Safe Zone.

MARPA Setup Menu

Velocity Reference—has two settings, Absolute and Relative. This
setting determines how speed and direction are displayed on the

To change a MARPA field option:

1. Using the ARROW KEYPAD, highlight the desired field and
press the ENTER key to activate the field selections.

2. Using the ARROW KEYPAD, highlight the desired selection.

3. Press the ENTER key to accept the change.

Vector Length—predicts the target’s approximate position at a set

MARPA List. Relative calculates target speed and direction relative to
your own. Absolute displays the target’s actual speed.

Hide/Show Navigation Features

This setting hides or shows navigation features such as Waypoints, a
Bearing Line and a Course Line on the Radar page. See page 16 for
more information on selecting the Navigation Features.

time interval. This setting determines the length of the Vector Line,
based on the time interval setting and the target’s speed. The time
interval settings range from .05 minutes to 60 minutes.

Target History—is a trail showing a targets movement. Target

Additional Adjustment Menu Items

There are three additional items available on the Adjustment Menu:
Map Cursor On/Off, Setup, and Enter Standby/Begin Transmitting.

History can be turned On or Off.

continued

GMR 20/40 Owner’s Manual 13

GMR 20/40 OPERATION > THE RADAR ADJUSTMENT MENU

Map Cursor On/Off

The Map Cursor On/Off setting turns the Map Page Cursor On or Off
when operating in Split Screen Mode or when using two MFDs.

To turn the Map Cursor On/Off:

Using the ARROW KEYPAD, highlight Map Cursor On/Off

and press the ENTER key.

Setup

Selecting Setup displays the Radar Setup Menu. The Radar Setup
Menu contains four sub-tabs: General, Display, MARPA, and
Advanced.

The General Tab

The General tab contains settings for Orientation, Cross-talk
Rejection, Front of Boat Offset, Timed Transmit, Timed Transmit
XMIT Time, and Timed Transmit STBY Time.

The General Tab

To change a Setup field option:

1. Using the ARROW KEYPAD, highlight the desired field and
press the ENTER key to activate the field selections.

2. Using the ARROW KEYPAD, highlight the desired selection.

3. Press the ENTER key to accept the change.

Orientation—configures the Radar page to display in one of three
Modes: Heading Up, North Up, or Course Up.

Cross-talk Rejection—

radar cross-talk may occur when two or
more radar equipped vessels are operating in proximity to one
another. Cross-talk rejection automatically filters out the cross-talk
interference.

14 GMR 20/40 Owner’s Manual

GMR 20/40 OPERATION > THE RADAR ADJUSTMENT MENU

Front of Boat Offset—this setting is used to correct for any
alignment error that may have occurred during installation of the
scanner. The scanner is directional. For optimal performance it needs
to be pointed directly ahead of the boat. To verify that the scanner
is properly aligned, point the bow of the boat directly at a stationary
object such as a buoy. Check the radar screen to verify that the object

Timed Transmit STBY Time—

interval in minutes that the radar is in stands by. For example, if set to
10min, the radar stands by for a period of ten minutes before referring
to the Timed Transmit XMIT Time. When the radar is standing by, the
scanner does not rotate or transmit; however power is still applied to
the Magnetron, eliminating the need for a warm-up cycle.

is shown directly ahead of the boat. If it is not, highlight the slider and
move it left or right using the ARROW KEYPAD until the object is
displayed directly in front of the boat. When you are satisfied with the
alignment, press the ENTER key to accept the change.

The Display Tab

The Display tab contains settings for: Center Offset, Rings,
Background color, Heading Line, Bearing Reference, and Navigation
Features.

Timed Transmit—is used to save power, likely while at anchor.
When Timed Transmit is

On, the radar refers to the settings in Timed
Transmit XMIT Time and Timed Transmit STBY Time. If Off is
selected, the Timed Transmit XMIT Time and Timed Transmit STBY
Time fields are inactive.

Timed Transmit XMIT Time—

this setting determines a time
interval in minutes the radar transmits. For example, if set to 01min,
the radar transmits for a period of one minute before referring to the
Timed Transmit STBY Time.

this setting determines a time

The Display Tab

GMR 20/40 Owner’s Manual 15

GMR 20/40 OPERATION > THE RADAR ADJUSTMENT MENU

Center Offset—has three settings: Center, Look Ahead, and Auto
Shift. Center places your current location in the center of the display.

The MARPA Tab

See MARPA Setup on page 12.
Look Ahead shifts your current location toward the bottom of the
display, allowing you to view an area farther ahead. Auto Shift adjusts
your location on the display according to the current speed.

Rings—is used to turn the radar Range Rings On or Off.

Background—

is used to select a background color for the Radar

The Advanced Tab

AFC Mode—has two settings, Auto, and Manual. In Auto Mode the

scanner frequency is automatically adjusted for optimal performance

and is recommended.

page. The options are Black, Blue, and White.

Heading Line—is used to turn the Heading Line On or Off.

Bearing Reference—has two settings, Absolute and Relative.

Relative calculates the bearing relative to own vessel heading.
Absolute calculates the bearing referring to North.

Navigation Features—there are three selectable Navigation
Features: Waypoints, Bearing Line, and Course Line. When selected,
that feature is displayed on the Radar page.

• Waypoints

Bearing Line—when selected displays a Bearing Line on the

•
Radar page. The Bearing Line is displayed as a line from your

—displays user waypoints on the Radar page.

The Advanced Tab

current position to the active destination waypoint, similar to
a traditional lollipop.

Course Line—when selected displays a Course Line from

•
your starting point to the active destination waypoint, similar
to navigation on a map.

16 GMR 20/40 Owner’s Manual

GMR 20/40 OPERATION > THE RADAR ADJUSTMENT MENU—MAP PAGE RADAR OVERLAY

To select an AFC Mode:

1. Using the ARROW KEYPAD, highlight the AFC Mode field

and press the ENTER key.

2. Using the ARROW KEYPAD, highlight the desired selection

and press the ENTER key.

To manually adjust the scanner frequency:

1. Using the ARROW KEYPAD, highlight the Freq button and

press the ENTER key.

2. Using the ARROW KEYPAD, adjust the scanner frequency up

or down to achieve the desired effect.

3. Press the ENTER key to accept the frequency change.

Note: The Signal Strength bar graph is damped and may be slow
when responding to frequency tuning changes.

Map Page Radar Overlay

Radar information can be displayed as an overlay on the Map page.
With radar information overlaid on the map, many of the radar
options are available by pressing the ADJ key.

It is important to note that changing the “Range” of the map does not
change the scanner range. When the Map page is zoomed in or out,
the radar overlay is scaled to fit.

To overlay Radar Data on the Map page:

Enter Standby/Begin Transmitting

Selecting Enter Standby places the Scanner into Standby Mode
While in Standby Mode, the Scanner does not transmit, but power
remains applied to the Magnetron.

If the scanner is in Standby Mode, Begin Transmitting is enabled.
Selecting Begin Transmitting removes the scanner from Standby
Mode and after “Spinning Up” the scanner begins transmitting.

To select Enter Standby or Begin Transmitting:

Using the ARROW KEYPAD, highlight the Enter Standby or

Begin Transmitting and press the ENTER key.

1. Press the ADJ key.

2. Using the ARROW KEYPAD, highlight Show Radar and
press the ENTER key.

To hide the Radar Overlay:

1. Press the ADJ key.

2. Using the ARROW KEYPAD, highlight Radar Options and
press the ENTER key.

3. Using the ARROW KEYPAD, highlight Hide Radar and press
the ENTER key.

GMR 20/40 Owner’s Manual 17

GMR 20/40 OPERATION > MAP PAGE RADAR OVERLAY

Map page with radar overlay Radar page

There are several Radar Options available on the Map page. These
options do affect operation of the radar and the Radar page.

Map page Radar Options

To display the

1. Press the ADJ key.

2. Using the ARROW KEYPAD, highlight Radar Options and
press the ENTER key.

Radar Options:

18 GMR 20/40 Owner’s Manual

APPENDIX

European License Requirements

Austria I Luxembourg I
Belgium G The Netherlands I
Czech Republic I Poland G
Denmark G Portugal G
Estonia * Slovakia *
Finland I Slovenia G
France G Spain *
Germany G Sweden G
Greece G United Kingdom I
Hungary * Cyprus G
Ireland * Malta *
Italy G Iceland G
Latvia I Norway I
Lithuania G Switzerland I

I—Requires an individual license for operation.

G—can be operated under a general license or license exemption.

APPENDIX > EUROPEAN LICENSE REQUIREMENTS

* This product may require licensing in your country of use. Please
refer to the national radio or telecommunications office or ministry.

GMR 20/40 Owner’s Manual 19

APPENDIX > SPECIFICATIONS

Specifications

Unit Dimensions: 28” (710 mm) D x 8” (205 mm) H.

Radar Scanner Weight:

Range Scales (Range Rings): GMR 40 — 1/8 nm (1/32 nm) to 36

nm (9 nm) GMR 20 — 1/8 nm (1/32 nm) to 24 nm (6 nm).

Power Output: GMR 20: 2 kW / GMR 40: 4kW.

Power Input Source: 10-35 v D.C. 28W.

Operating Temperature Range:

humidity up to 95% at 35°C.

Beamwidth: Horizontal beamwidth of 3.6° nominal / Vertical
beamwidth of 25° nominal.

Range: GMR 20: 24 nm / GMR 40: 36 nm.

Wind Velocity: Wind speed up to 100 Kts.

Antenna RPMs: 24 rpm.

Range Ring Accuracy: +/- 1 meter.

Bearing Accuracy:

Minimum Range: 35 meters

Unit 26 lbs; cable 8.35 lbs.

-25°C to 70°C, and a relative

1°

Sensitivity and Tune Controls: Gain, Sea Clutter, Rain Clutter,
Frequency Tune.

Radar/Chart Synchronization:

standard radar presentation.

Off Center Function: Look ahead, Auto Shift, and Manual.

RF Transmit Frequency:

Overlay Mode. Split overlay with

9410 ± 30 MHz

Range Discrimination: 30 meters

20 GMR 20/40 Owner’s Manual

FCC Compliance

The GMR 20/40 complies with Part 80 of the FCC rules. It has
received a grant of equipment authorization, issued under the authority
of the FCC.

This equipment generates, uses and can radiate radio frequency
energy and, if not installed and used in accordance with
the instructions, may cause harmful interference to radio
communications. However, there is no guarantee that interference
will not occur in a particular installation. If this equipment does
cause harmful interference to radio or television reception, which
can be determined by turning the equipment off and on, the user is
encouraged to try to correct the interference by one of the following
measures:

• Reorient or relocate the receiving antenna.

• Increase the separation between the equipment and the receiver.

• Connect the equipment into an outlet on a circuit different from

that to which the receiver is connected.

• Consult the dealer or an experienced radio/TV technician for

help.

APPENDIX > FCC COMPLIANCE

GMR 20/40 Owner’s Manual 21

APPENDIX > SOFTWARE LICENSE AGREEMENT / LIMITED WARRANTY

Software License Agreement

BY USING THE GMR 20/40, YOU AGREE TO BE BOUND
BY THE TERMS AND CONDITIONS OF THE FOLLOWING
SOFTWARE LICENSE AGREEMENT. PLEASE READ THIS
AGREEMENT CAREFULLY.

Garmin grants you a limited license to use the software embedded in
this device (the “Software”) in binary executable form in the normal
operation of the product. Title, ownership rights and intellectual
property rights in and to the Software remain in Garmin.

You acknowledge that the Software is the property of Garmin and
is protected under the United States of America copyright laws and
international copyright treaties. You further acknowledge that the
structure, organization and code of the Software are valuable trade
secrets of Garmin and that the Software in source code form remains
a valuable trade secret of Garmin. You agree not to decompile,
disassemble, modify, reverse assemble, reverse engineer, or reduce
to human readable form the Software or any part thereof or create
any derivative works based on the Software. You agree not to export
or re-export the Software to any country in violation of the export
control laws of the United States of America.

LIMITED WARRANTY

This Garmin product is warranted to be free from defects in materials
or workmanship for one year from the date of purchase. Within
this period, Garmin will at its sole option, repair or replace any
components that fail in normal use. Such repairs or replacement will
be made at no charge to the customer for parts or labor, provided that
the customer shall be responsible for any transportation cost. This
warranty does not cover failures due to abuse, misuse, accident or
unauthorized alteration or repairs.

THE WARRANTIES AND REMEDIES CONTAINED HEREIN
ARE EXCLUSIVE AND IN LIEU OF ALL OTHER WARRANTIES
EXPRESS OR IMPLIED OR STATUTORY, INCLUDING
ANY LIABILITY ARISING UNDER ANY WARRANTY OF
MERCHANTABILITY OR FITNESS FOR A PARTICULAR
PURPOSE, STATUTORY OR OTHERWISE. THIS WARRANTY
GIVES YOU SPECIFIC LEGAL RIGHTS, WHICH MAY VARY
FROM STATE TO STATE.

IN NO EVENT SHALL GARMIN BE LIABLE FOR ANY
INCIDENTAL, SPECIAL, INDIRECT OR CONSEQUENTIAL
DAMAGES, WHETHER RESULTING FROM THE USE, MISUSE,
OR INABILITY TO USE THIS PRODUCT OR FROM DEFECTS
IN THE PRODUCT.

22 GMR 20/40 Owner’s Manual

Some states do not allow the exclusion of incidental or consequential
damages, so the above limitations may not apply to you.

Garmin retains the exclusive right to repair or replace the unit
or software or offer a full refund of the purchase price at its sole
discretion. SUCH REMEDY SHALL BE YOUR SOLE AND
EXCLUSIVE REMEDY FOR ANY BREACH OF WARRANTY.

Garmin International, Inc.

To obtain warranty service, contact your local Garmin authorized
dealer. Or call Garmin Product Support at one of the numbers shown
below, for shipping instructions and an RMA tracking number. The
unit should be securely packed with the tracking number clearly
written on the outside of the package. The unit should then be sent,

1200 Ease 151st Street
Olathe, Kansas 66062, U.S.A.
Phone: [phone]
USA Only: 800/800.1020
FAX: [phone]

freight charges prepaid, to any Garmin warranty service station. A
copy of the original sales receipt is required as the proof of purchase
for warranty repairs.

Garmin (Europe) Ltd.
Unit 4, The Quadrangle, Abbey Park Industrial Estate
Romsey, S051 9DL, U.K.

Products sold through online auctions are not eligible for rebates or
other special offers from Garmin. Online auction confirmations are

Phone: [phone]
FAX: [phone]

not accepted for warranty verification. To obtain warranty service,
an original or copy of the sales receipt from the original retailer is
required. Garmin will not replace missing components from any
package purchased through an online auction.

Garmin Corporation
No. 68, Jangshu 2nd Road, Shijr, Taipei County, Taiwan
Tel. [phone]
Fax [phone]

APPENDIX > LIMITED WARRANTY

Note: The GMR 20/40 does not contain any user-serviceable
parts. Repairs should only be made by an authorized Garmin
service center. Unauthorized repairs or modifications could result
in permanent damage to the equipment, and void your warranty.

GMR 20/40 Owner’s Manual 23

APPENDIX > WARNINGS AND CAUTIONS

Warning and Cautions

CAUTION: Use the GMR 20/40 at your own risk. To reduce the
risk of unsafe operation, carefully review and understand all aspects
of this Owner’s Manual, and thoroughly practice operation using the
simulator Mode prior to actual use. When in actual use, carefully
compare indications from the GMR 20/40 to all available navigation
sources, including the information from other NAVAIDs, visual
sightings, charts, etc. For safety, always resolve any discrepancies
before continuing navigation.

CAUTION: IT IS THE USER’S RESPONSIBILITY TO USE
THIS PRODUCT PRUDENTLY. THIS PRODUCT IS INTENDED
TO BE USED ONLY AS A NAVIGATIONAL AID AND MUST
NOT BE USED FOR ANY PURPOSE REQUIRING PRECISE
MEASUREMENT OF DIRECTION, DISTANCE, LOCATION, OR
TOPOGRAPHY.

WARNING: This product, its packaging, and its components
contain chemicals known to the State of California to cause cancer,
birth defects, or reproductive harm. This Notice is being provided
in accordance with California’s Proposition 65. If you have any
questions or would like additional information, please refer to our
web site at http://www.garmin.com/prop65.

WARNING: The radar scanner transmits electromagnetic energy.
Ensure that the scanner has been installed according to the
recommendations given in this guide, and that all personnel are clear
of the scanner, before switching to transmit Mode.

24 GMR 20/40 Owner’s Manual

INDEX

D

Index

A

About This Manual i
Adjustment 5
Adjustment Menu 5
Advanced Tab
AFC Mode 16, 17

16

Define a Guard Zone 10
Digital Navigation Data 3, 4
Display Tab

15

E

EBL 10
Electronic Bearing Line 10
Enter Standby 13, 17
European License Requirements 19

F

B

Background 16
Background color 15
Bearing Line 16
Bearing Reference 15, 16
Begin Transmitting
Begin Transmitting. 13

17

C

Caution 2
Center Offset 15, 16
change Sea Clutter setting 7
change the Gain 6
Clear Trails
Configuration 5
Course Line 16
Cross-talk Rejection 14

9

Fast Time Constant 7
FCC Compliance 21
Features 3
Front of Boat Offset
FTC 5, 7

15

G

Gain 5, 6
General Tab 14
Guard Zone 5, 9

H

Heading Line 3, 4, 15, 16
Heading Sensor 11
Hide/Show Navigation Features 5
Highlight i

L

Limited Warranty 22

GMR 20/40 Owner’s Manual 25

M

Manually Adjust the Scanner 17
Map Cursor 13
Map Cursor On/Off
Map Page Radar Overlay 17
MARPA 5, 11
MARPA function 11
MARPA List
MARPA Setup
MARPA Setup Menu
MARPA Tab 16
MARPA target 11
Mini Automatic Radar Plotting Aid

14

12

12

12

N

Navigation Features 5, 13, 15, 16

O

Orientation 14
Overlay 17
Overview 1
Own Vessel Safe Zone 13

R

Radar Adjustment Menu 5
Radar Configuration 5
Radar Configuration Page
Radar Options 18
Radar Overlay 17
Radar Overview 1

5

Radar Page 1
Radar Page Layout 3
Radar Warming Up 2
Rain Clutter 5, 7
Range Rings 3, 4
Rings 15, 16
Ring Separation 3

S

Safety feature 2
Safe Zone Ring 13
Sea Clutter 5, 6
Setup 13, 14

11

Signal Strength 17
Software License Agreement
Software update 1
Soft Key options 3
Specifications
Spinning Up 2
Standby Mode 2
Status Bar 2, 3

T

Target Expansion 5, 8
Target History
Terminology
Timed Transmit
Timed Transmit STBY Time
Timed Transmit XMIT Time
Time To Safe Zone
Trails

5, 9

22

20

13

i

15

15
15

13

INDEX

V

Variable Range Marker 10
Vector Length
Velocity Reference
VRM/EBL

13

13

5, 10

W

Warming Up 2
Warning and Cautions 24
WARRANTY 22
Waypoints

16

Z

Zoom 5, 8
Zoom level 8
Zoom Scale 3

26 GMR 20/40 Owner’s Manual

For the latest free software updates (excluding map data) throughout the life of your

Garmin products, visit the Garmin Web site at www.garmin.com.

© Copyright 2005 Garmin Ltd. or its subsidiaries

Garmin International, Inc.

1200 East 151st Street, Olathe, Kansas 66062, U.S.A.

Garmin (Europe) Ltd.

Unit 5, The Quadrangle, Abbey Park Industrial Estate, Romsey, SO51 9DL, U.K.

Garmin Corporation

No. 68, Jangshu 2nd Road, Shijr, Taipei County, Taiwan

www.garmin.com

Part Number 190-00457-00 Rev.

A