Garmin GPS 48 12 Channel Manual

The Garmin GPS 48 is a rugged, waterproof 12-channel GPS receiver designed for marine, aviation, and outdoor navigation. It features a high-contrast LCD display, NMEA 0183 interface for connecting to autopilots and chartplotters, built-in worldwide basemap, waypoint and route storage, track log recording, and multiple navigation screens. Below are key sections for operation, features, installation, setup, and troubleshooting.

Features at a Glance

Key components: 12-parallel-channel GPS receiver, waterproof case (IPX7), backlit LCD, external antenna port, NMEA 0183 data interface, serial data port.

Installation & Mounting

Unpack and inspect contents. Choose mounting location with clear view of sky.

1. Select Mounting Location: Ensure clear view of sky for optimal satellite reception.
2. Flush Mounting: Use provided template to cut hole; secure with mounting hardware.
3. Bracket Mounting: Attach bracket to flat surface using screws; secure unit to bracket.
4. Connect Power: Red wire to positive (+), black wire to negative (-) of 10-40 VDC source.
5. Connect External Devices: Use NMEA 0183 wires to connect to compatible devices.

WARNING! Ensure power is off during installation. Do not mount near magnetic compasses.

First-Time Setup

Apply power; unit begins satellite acquisition.

1. Initialization: Upon first power-up, unit may need several minutes to acquire satellites and determine location.
2. Set Preferences: Press MENU, navigate to Setup menu to set units (nautical miles, statute miles, kilometers), time format, datum (WGS 84 default).
3. Backlight Adjustment: Press and hold PAGE button to adjust backlight level.
4. Configure NMEA Output: In Interface menu, select NMEA 0183 version and baud rate (4800 default).

CAUTION! Ensure proper polarity when connecting power to avoid damage.

Specifications

• Receiver: 12 parallel channels, tracking all satellites in view.
• Update Rate: 1 second continuous.
• Accuracy: <15 meters RMS, 3 meters RMS with WAAS enabled.
• Acquisition Time: Warm start ~15 seconds, cold start ~45 seconds.
• Interface: NMEA 0183 v2.0, RTCM 104 DGPS corrections input.
• Waypoints: 500 with names and symbols.
• Routes: 20 reversible routes, 30 waypoints each.
• Tracks: 10 saved tracks, 750 points each.
• Power: 10-40 VDC, 1.5 watts typical.
• Waterproof: IPX7 standard.
• Operating Temp: -15°C to 70°C (5°F to 158°F).

Controls and Display

Front Panel: POWER key, PAGE key, ENTER/MARK key, QUIT key, ROCKER keypad (up/down/left/right).

Display Screens: Satellite Status, Position, Map, Highway, Navigation, Menu.

Satellite Status: Shows satellite signal strength and position fix status. Position: Displays coordinates, altitude, time, and accuracy. Map: Shows current position, waypoints, and track. Highway: Steering screen with course deviation indicator. Navigation: Provides bearing, distance, speed, and time to destination. Menu: Access to waypoints, routes, tracks, setup, and system functions.

Connecting to External Devices

NMEA 0183: Connect to autopilot, chartplotter, sounder, or PC. External Antenna: For improved reception in covered areas.

1. Turn off power to GPS 48 and external device before connecting.
2. Identify NMEA wires: TX (transmit) and RX (receive) for data; Ground.
3. Connect GPS 48 NMEA Out (+) to device NMEA In (+), and Ground to Ground.
4. For external antenna, connect active antenna to external antenna port.

Tip: Refer to your external device's manual for specific NMEA connection details.

Basic Navigation Operations

Creating and navigating to waypoints and routes.

1. Mark Waypoint: Press and hold ENTER/MARK at desired location; edit name/symbol if needed.
2. Go To Waypoint: From any screen, press GOTO, select waypoint from list or enter identifier.
3. Create Route: Press MENU, select Routes > New Route. Add stored waypoints in sequence.
4. Follow Route: From Route list, select desired route and choose Navigate.
5. Track Back: Navigate your exact path in reverse using saved track log.
6. Man Overboard (MOB): Press and hold GOTO quickly marks MOB position and begins navigation back.

WARNING! GPS is an aid to navigation. Always use in conjunction with proper charts and situational awareness.

Advanced Features

DGPS (Differential GPS): Connect to external DGPS beacon receiver via NMEA input for improved accuracy. Proximity Waypoints: Set alarm radius around a waypoint. Sun/Moon Information: Access times for sunrise, sunset, moonrise, moonset. System Tests: Perform built-in diagnostic tests for display and buttons.

Care & Maintenance

Clean with fresh water and mild soap if used in saltwater environment. Use soft, damp cloth for display. Do not use harsh chemicals or abrasives.

CAUTION! Ensure unit is powered off and disconnected before cleaning. Do not open case; no user-serviceable parts inside.

Regulatory Information

FCC Compliance: This device complies with Part 15 of the FCC Rules. Operation is subject to condition that it does not cause harmful interference. This device must accept any interference received. Copyright © Garmin Ltd. or its subsidiaries. Garmin and the Garmin logo are trademarks of Garmin Ltd. or its subsidiaries. For support, visit www.garmin.com/support or contact Garmin Product Support.

Troubleshooting

Reset: To restore factory defaults, power off. Press and hold PAGE and QUIT while powering on. Release buttons after beep.

Service: For repairs, contact Garmin Product Support. Do not attempt to service unit yourself.