Garmin GPSMAP 198C Sounder Manual

The Garmin GPSMAP 198C Sounder is a combined GPS chartplotter and fishfinder featuring a high-resolution color TFT display, built-in worldwide basemap, dual-frequency sonar capability (50/200 kHz), external GPS antenna input, NMEA 0183 interface, waterproof construction (IPX7), and support for Garmin BlueChart and MapSource cartography. Below are key sections for safety, features, installation, setup, operation, and troubleshooting.

1. Features at a Glance 2. Installation 3. First-Time Setup 4. Specifications 5. Controls and Settings 6. Connecting Devices 7. Using GPS & Sonar 8. Navigation Features 9. Care & Maintenance 10. Regulatory Information 11. Troubleshooting

Features at a Glance

Key components: Waterproof display unit, GPS antenna, Transducer, Power/data cable, Mounting hardware, Remote control (optional).

Feature	Description
Display	5-inch diagonal, 256-color TFT LCD, sunlight readable
GPS Receiver	12 parallel channel, WAAS enabled
Sonar	Dual-frequency (50/200 kHz), depth capability to 3000 ft
Chartplotter	Built-in worldwide basemap, accepts BlueChart cards
Waypoints/Routes	3000 waypoints, 50 reversible routes
Interfaces	NMEA 0183 input/output, RS-232 data port
Power Input	10-40 VDC, 1.5A max
Waterproof Rating	IPX7 (submersible to 1 meter for 30 minutes)
Audio Alarms	Anchor drag, arrival, off-course, depth, temperature
Backlight	Adjustable LED backlight for night viewing

Installation

Unpack and inspect contents. Choose suitable mounting location.

Mount display unit: Use included bracket on flat, vibration-free surface.
Install transducer: Mount transom or through-hull following included template.
Connect GPS antenna: Route cable to clear view of sky, connect to GPS port.
Connect power: Red to positive (10-40 VDC), black to negative ground.
Connect NMEA devices: Use NMEA 0183 wires for autopilot or other instruments.

WARNING! Ensure all connections are waterproofed. Route cables away from engine interference.

First-Time Setup

Power on unit; follow initial setup prompts.

Acquire GPS signal: Place antenna with clear sky view; wait for 3D fix.
Set units: In SETUP menu, select nautical/statute miles, feet/fathoms/meters.
Calibrate compass: Follow on-screen instructions for electronic compass (if equipped).
Set alarms: Configure depth, anchor drag, and arrival alarms as needed.
Load maps: Insert BlueChart or MapSource data card in card slot.

CAUTION! Do not power on until all connections are secure and waterproofed.

Specifications

Display: 5-inch diagonal, 320 x 240 pixels, 256-color TFT.
GPS: 12 parallel channel, WAAS/EGNOS enabled, position accuracy < 10 meters.
Sonar: Dual-frequency 50/200 kHz, 500W RMS, depth to 3000 ft (915m).
Waypoints: 3000 with name and symbol.
Routes: 50 reversible routes with up to 50 waypoints each.
Tracks: 10 saved tracks, 3000 points each.
Power: 10-40 VDC, 1.5A max, reverse polarity protected.
Operating Temp: -15°C to 70°C (5°F to 158°F).
Waterproof: IPX7 standard.
Dimensions: 6.3" W x 4.7" H x 2.4" D (160 x 119 x 61 mm).

Controls and Settings

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

On-Screen Menus: PAGE cycles between GPS Map, Sonar, Highway, and Data pages. SETUP menu: Units, Alarms, System, NMEA, Display, Sounds.

Sonar Settings: Frequency (50/200 kHz), Range (auto/manual), Gain, Noise rejection, Surface clarity, Chart speed. GPS Settings: Datum (WGS84 default), North reference (True/Magnetic), Coordinate format. Display: Contrast, Backlight, Color scheme (Day/Night).

Connecting Devices

NMEA 0183: Connect to autopilot, AIS, or other NMEA devices. Data Card: Insert BlueChart or MapSource card. External GPS: Use GPS antenna port.

Turn off power before making connections.
Use shielded cable for NMEA connections; keep away from power cables.
Ensure proper polarity for NMEA in/out connections.
Waterproof all external connections with marine-grade sealant.

Tip: Test all connections before final installation.

Using GPS & Sonar

Supports simultaneous GPS navigation and fishfinding.

View GPS: Press PAGE to select Map page; see position, course, speed.
Create waypoint: Press MARK at current location; edit name/symbol.
Navigate to waypoint: Use GOTO function; follow on-screen bearing.
View sonar: Press PAGE to Sonar page; adjust settings for best image.
Use split-screen: Display GPS map and sonar simultaneously.
Track plotting: Activate track plot to record path.
Man overboard: Press and hold MARK for 3 seconds for instant MOB waypoint.
Sonar recording: Record bottom contours to data card (optional).

WARNING! GPS accuracy may degrade near structures or in poor signal conditions.

Navigation Features

Tides: Display tide stations (with compatible BlueChart). Routes: Create and follow multi-point routes. Alarms: Anchor drag, arrival, off-course, depth, temperature. Data Fields: Customize up to 8 data fields on navigation pages.

Care & Maintenance

Use fresh water to rinse after saltwater use. Clean screen with soft, damp cloth only. Store in dry place when not in use.

CAUTION! Do not use harsh chemicals, solvents, or abrasive cleaners. Ensure connectors remain clean and dry.

Regulatory Information

FCC Compliance: Part 15 Class B device. CE Marked. NMEA 0183 compliant. Copyright © Garmin Ltd. or its subsidiaries. For support, visit www.garmin.com or contact Garmin Product Support at 913-397-8200 (US) or your local distributor.

Troubleshooting

Symptom	Possible Cause	Corrective Action
No power	Power connection/fuse	Check 3A fuse; verify 10-40 VDC at power cable; check polarity.
No GPS signal	Antenna obstruction	Ensure clear view of sky; check antenna connection; allow 5+ minutes for first fix.
No sonar display	Transducer/connections	Verify transducer installation; check connections; ensure in water.
Inaccurate depth	Transducer interference	Adjust transducer location away from turbulence; adjust gain.
Display dim	Backlight setting	Increase backlight in SETUP > Display menu.
Waypoints not saving	Memory full	Delete unused waypoints; reset to factory defaults if needed.

Reset: Hold PAGE + POWER during startup for system reset.

Service: Contact Garmin Product Support or authorized service center.