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Garmin 198C Review

The Garmin 198C we tested came equipped from the factory with an external GPS antenna/sensor, an integral 500-watt sounder, and a dual-frequency transducer. It has an internal world map built-in to memory and uses Garmin BlueChart cartography to enhance map details.

The display unit case is just over 6-inches high, 6-inches wide, and nearly 4-inches deep.

garmin 198c chartplotter

Garmin 198c

Wiring for power, interface, and transducer leads hooks to the back of the unit with a single multi-pin twist-lock connector. The transducer branch connects to the transducer with another inline twist-lock connector.

A factory installed connector on the display unit end of the antenna cable makes connecting it a snap. Also, the 198C has tapped holes in the back of the case to facilitate flush mounting. Installation was simple and straightforward.

Screen Size and Viewability

The Garmin 198C screen is 3-inches wide and slightly over 4-inches high yielding a diagonal measurement of 5-inches. It has a resolution of 234 x 320 pixels.

At this resolution details are not as sharp as they appear on newer high resolution screens. It has thirteen levels of control for screen brightness and contrast. The brightness control range was adequate and the contrast control effective.

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Two color palettes, sun or dark, can be selected from the map tab on the main menu. In daylight conditions, it showed some screen darkening when viewed with polarized sunglasses. Some intermittent screen fogging was noted in the center of the screen. We rated the screen good for both daytime and nighttime viewability. Pushbuttons and the cursor pad are backlit.


Most functions on the 198C are controlled through multi-layered menus. Hitting the menu key twice brings up the main menu with a long list of items in tabular format on the left side of the screen, selecting a tab opens another menu page where you can make and execute selections.


Waypoints can be saved at the boat’s position by pressing and holding the enter/mark key. This brings up a data box with waypoint information that includes a symbol, up to 40 are selectable, a name up to a 10-characters long, a 20-character comment line, lat/long, and a few other pieces of information concerning the waypoint. Any of the information can be modified.

To change the name you’ll need to scroll through number and letters, a slow and tedious process but a common method in machines of this size and expense. Symbols are chosen from a list onscreen.


Route entry is accomplished using waypoint list or by selecting points on the map page. We created a route for navigation by using the quick route entry function using only the cursor and the enter button.

Odds and Ends

garmin 198c chartplotter

The Garmin 198C can display sounder and map in split screen.

The map can be oriented north up, track up, or course up. We tried them all and they worked properly most of the time. Once following a course reversal in the course up mode the 198C map failed to flip around and follow the boat path, every other time it worked properly. The course predictor is a thin line and can be somewhat hard to see on a fully detailed map page.

Garmin’s man overboard function is activated by pressing the mob key. The machine then asks whether you want to navigate to the mob position. If you hit yes it changes to a map page offering little useful data on which to navigate precisely back the mob position (unless you have the data blocks on the map page turned on). To overcome this we simply pressed the page button and got the needed info on another page.

A number of different pages are displayed by pressing the page button. Additional options for the currently displayed page can be selected by hitting the menu key once. This brings up page specific data. Some pages on the Garmin can be displayed in vertical or horizontal windows that are user adjustable in size.


The 500-watt sounder integral to the 198C includes a dual frequency transducer (50/200 kHz) and a list of features including auto and manual depth ranging, zoom, bottom lock, monochrome A-scope (flasher in Garmin parlance), and water temperature display.

What makes the sounder really standout is active cursor control of a whole slew of desirable functions. If you need to adjust the gain for a specific target all you need to do is use the right/left arrows on the cursor to select gain then press the up/down cursor to increase of decrease the gain as needed. Nine functions are available with the active cursor with gain, zoom, depth range, and frequency among the most useful.

We rated the Garmin 198C sounder good for presentation and excellent for ease of use.

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Final Thoughts

Although the Garmin 198C is now discontinued we found this upgrade to the venerable 188C to have good functionality, decent screen resolution, and an easy to use sounder.