Overview

The Garmin GMR Fantom is a solid-state marine radar family offered as 18 inch and 24 inch radomes, plus 4 ft and 6 ft open-array scanners, so you can match your mounting space and the kind of target separation you want at the helm. The radome models output 50 W peak, rotate up to 60 RPM, and reach up to 48 nautical miles with a 6 m minimum range; they run on 10 to 32 Vdc and draw up to 4 A.

On screen, MotionScope Doppler highlighting helps you spot moving targets in traffic and weather. Features like target-size adjustment, true echo trails, dual range, radar overlay, and automatic gain and sea-clutter filtering are controlled from a compatible Garmin chartplotter on the network.

Key features

• Radome choices: 18 inch (5.2° beam width) or 24 inch (3.7° beam width), both 50 W peak output with up to 60 RPM rotation.
• Radome range coverage: 6 m minimum range and up to 48 nautical miles maximum range.
• 10 to 32 Vdc input for the family; radome units are rated up to 4 A max with a 7.5 A fuse.
• MotionScope Doppler highlighting to separate moving targets from stationary returns.
• Timed transmit and power-save operation options for managing draw when you do not need continuous transmission.
• Dual range and radar overlay support on compatible chartplotters for close and far views at the same time.
• Open-array options: 4 ft or 6 ft antennas with 50 W, 120 W, or 250 W output ratings; horizontal beam width is 1.8° (4 ft) or 1.25° (6 ft).
• Open-array environmental and install specs: IPX6 water rating (IEC 60529), maximum wind load 80 kn, and 15 m (49 ft 3 in) power and network cable lengths listed for the system.

Variants

Configurations differ by scanner style (radome or open array), antenna size, finish color (black or white), and output power rating.

Radomes are offered in 18 inch or 24 inch housings at 50 W. Open-array versions use a 4 ft or 6 ft antenna and are available in 50 W, 120 W, or 250 W outputs.

Compatibility and system integration

The radar connects to a compatible Garmin chartplotter over Garmin networking, and all operation is handled from the chartplotter interface. This includes selecting the installed antenna size and setting the front-of-boat offset if the scanner cannot be aligned perfectly with the bow.

Installation and fit

For the 18 inch radome, allow a footprint around 508.2 mm long by 504.7 mm wide with a height of 248.3 mm. The 24 inch radome is around 645.4 mm long by 642.5 mm wide with a height of 250.3 mm. Mount the scanner on a level surface with a clear view, keep it away from heat sources and rigging, and plan cable routing so bends stay gentle and the deck penetration can be sealed.

Compass separation varies by model: 97 cm for the 18 inch radome, 89 cm for the 24 inch radome, and 30 cm for the open-array pedestal. For temperature exposure, dome ratings differ by color (white: -25°C to 70°C; black: -25°C to 55°C), and open-array operating range is -15°C to 55°C.

Power and wiring

Both radome and open-array models operate from 10 to 32 Vdc, which fits common 12 V and 24 V systems. Radome draw varies by mode and range setting, with low standby draw (up to 4 W) and transmitting power consumption up to 33 W in normal mode or up to 24 W in power save mode.

Open-array power cables include a 15 A in-line fuse, and some models use a voltage converter; in those setups a 30 A fuse is installed between the battery and converter in addition to the in-line fuse. This approach helps keep voltage stable on longer runs up a mast or radar arch.

Use cases on board

This radar family is a good match for boats already running a Garmin chartplotter and network, whether you need a radome that fits on a smaller hardtop or an open array that uses a narrower beam for picking targets out of shoreline clutter. It is commonly used for coastal cruising, night runs, fog, and keeping situational awareness in busy approaches and passes.