GMR Fantom™ 256 Black - 250 W radar with 6-foot open-array antenna and pedestal

The Garmin GMR Fantom™ 256 radar is an open-array solid-state radar with a transmission power of 250 W. It offers a detection range from 6 meters to 96 nautical miles, with a horizontal beam width of 1.25° and vertical beam width of 23°. It has rotation speeds of 24 and 48 RPM.

The GMR Fantom™ 256 radar integrates several advanced technologies:

MotionScope™: Uses Doppler effect to identify moving targets via color coding, facilitating collision avoidance and weather tracking. Pulse compression: Ensures high-resolution imaging and better target identification. MARPA: Enables automatic acquisition and tracking of up to 30 moving targets. Filters such as Scan-to-Scan Averaging and Dynamic are also included to enhance radar image quality.

The GMR Fantom™ 256 radar offers detection range from 6 meters to 96 nautical miles, ensuring complete monitoring of the marine environment.

The Garmin GMR Fantom™ 256 radar is a solid-state model with a 250 W transmit power, making it Garmin's most powerful solid-state radar for the consumer market.

The GMR Fantom™ 256 radar antenna offers rotation speeds of 24 and 48 rpm (revolutions per minute). The high-speed mode is available in single range up to 12 NM with MotionScope disabled.

For installation of the GMR Fantom™ 256 radar, the following tools are required:

A #2 Phillips screwdriverA 6 mm hex keyA drillA 15 mm (19/32 in) drill bitA 32 mm (1 1/4 in) drill bit (optional, for cable routing)A 17 mm (21/32 in) wrench and a torque wrenchA 3.31 mm² (12 AWG) copper wire for grounding (not included)Marine sealant

When choosing the mounting location, consider the following points:

The radar must be mounted out of reach of people, with the vertical beam above head height. It must be installed high above the vessel’s keel line with minimal obstruction of the radar beam. The mounting surface must be flat, parallel to the waterline, and sufficiently robust to support the radar’s weight. The location must allow connection to power, marine ground, and the network. Avoid mounting the radar near heat sources (exhausts, lights) or at the same height as horizontal spreaders or mast cross-trees. Maintain a safe distance from other electronic equipment and cables (more than 2 m from the radar beam path, more than 1 m from transmitting equipment and radio cables, more than 2 m from SSB radios). GPS antennas must be positioned above or below the radar beam path.

The radar (and voltage converter, if applicable) must be connected to an appropriate marine ground using 3.31 mm² (12 AWG) copper wire, which is not included. The wire must be routed to a marine ground point and to the radar pedestal. It must be connected to the ground connector on the pedestal, then the fitting and ground screw must be covered with marine sealant. The other end of the wire must be connected to the marine ground point.

The voltage converter for the GMR Fantom™ 256 radar requires an input voltage of 10 to 32 Vdc. It is recommended to install it as close as possible to the power source and to connect its power cable directly to the battery.

For radar installation, you will need to drill 15 mm (19/32 in) mounting holes. If you need to route power and network cables through the mounting surface, a 32 mm (1 1/4 in) hole can be drilled (optional). After running the cables, it is mandatory to apply marine sealant to ensure perfect watertightness.

After securely mounting the pedestal, remove the protective cover from the waveguide located on top of the pedestal. Then align the pedestal’s waveguide with the socket under the antenna and slide the antenna onto the pedestal. Secure the antenna to the pedestal by tightening the captive hex bolts under the antenna arm to a torque of 7.9 N·m (6 lbf·ft) to prevent damage to the antenna or mounting hardware.

When routing cables, it is critical to secure them with appropriate ties, fasteners, and sealant along their path and through bulkheads or the deck. Avoid running cables near moving objects, high-heat sources, or through doors and bilge areas. To prevent interference, do not route network and power cables parallel to other cables (radio antenna lines, power cables); if unavoidable, cables must be shielded with a metal conduit or EMI shielding. The power cable should be installed as close as possible to the battery source.

No, it is explicitly stated not to reuse the power adapters from previous Garmin radar models or third-party power adapters. Using any adapter other than the one included with the radar, or the correct adapter purchased from Garmin or an authorized Garmin dealer, could damage the radar or prevent it from powering on.

The Garmin GMR Fantom™ 256 radar is compatible with the Garmin BlueNet™ network or the Garmin Marine Network.

No, this device must be used only as a navigational aid. Using the radar for purposes requiring precise measurements or directions, distances, locations, or topographies may result in bodily injury or damage to the vessel.

The product warranty may be void if the power cable is connected without the appropriate inline fuse holder or if the unit is opened by anyone other than a Garmin authorized service technician. The device contains no user-serviceable parts.

While installation by a qualified marine installer is strongly recommended to ensure optimal performance and avoid potential damage to the device or the vessel, it is not explicitly mandatory. However, it is important to note that opening the device by anyone other than a Garmin authorized service technician will void the product warranty.

The radar transmits electromagnetic energy. To avoid potential personal injury or damage, ensure the radar is installed according to the instructions and that all personnel are clear of the radar beam path before transmission. It is also imperative not to look directly at the antenna up close while the radar is transmitting, as the eyes are the most sensitive part of the body to radiofrequency electromagnetic energy. Proper installation and operation ensure compliance with safety standards for human exposure to radiofrequency electromagnetic fields.

When selecting the mounting location for the GMR Fantom™ 256 radar, several key points are essential to ensure safety and optimal performance:

The radar must be mounted out of reach of people, with the vertical beam above head height. It is critical to respect the specified minimum safety distance to avoid exposure to harmful radiofrequency levels.

Mount the radar high above the vessel's keel line, ensuring minimal obstruction of the radar beam. A higher position allows for detection of more distant targets.

The mounting surface must be flat, sturdy, and parallel to the vessel's waterline, capable of supporting the radar's weight.

The location must allow for connection to the power supply, ground, and network.

Avoid mounting the radar near heat sources, such as exhausts or lights.

The radar must be mounted at a different height than horizontal spreaders and mast spreaders.

To avoid interference with a magnetic compass, respect the specified compass safety distance.

Other electronic devices and cables must be mounted more than 2 meters (6.5 feet) away from the radar beam path.

GPS antennas must be located either above or below the radar beam path.

Mount the radar at least 1 meter (40 inches) from any transmitting equipment and cables carrying radio signals (such as VHF radios and their antennas).

Mount the radar at least 2 meters (6.5 feet) from SSB radios.

The Garmin GMR Fantom™ 256 radar is designed for demanding marine navigation, offering high performance and advanced technologies:

Transmit power: This is a 250 W solid-state radar, the most powerful Garmin model for the consumer market.Detection range: It provides full environmental monitoring with a range from 6 m to 96 nautical miles.Beam width: Its horizontal beam width is 1.25° and vertical beam width is 23°, optimizing target detection.Rotation speeds: The radar offers rotation speeds of 24 and 48 rpm. The high-speed mode is available on a single range up to 12 nautical miles when MotionScope is disabled.Integrated technologies:MotionScope™: This technology uses Doppler to identify moving targets via color coding, aiding collision avoidance, bird finding, and weather tracking.Pulse compression: Ensures high-resolution imaging and improved target identification.MARPA: This function allows automatic acquisition and tracking of up to 30 moving targets.Advanced filters: The radar also includes Scan-to-Scan Averaging and Dynamic filters for enhanced clarity and detection.