Garmin GMR Fantom 254/256 radar pedestal

This pedestal is specifically designed to be compatible with Garmin GMR Fantom 254 and GMR Fantom 256 open array radar antennas.

To install the radar pedestal, you will need the following tools:

A Phillips screwdriver #2A 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 selecting the mounting location, consider the following:

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 to the radar beam. The mounting surface must be flat, parallel to the vessel's waterline, and sufficiently robust to support the radar's weight. The location must allow for connection to the power supply, ground, and network. Avoid mounting the radar near heat sources (exhausts, lights) or at levels similar to horizontal spreaders and transverse mast bars. Maintain a minimum distance of 2 m (6.5 ft) from other electronic equipment and cables, and at least 1 m (40 in) from transmitting equipment or cables carrying radio signals (VHF). For SSB radios, allow at least 2 m (6.5 ft).

The radar pedestal (and the voltage converter, if applicable) must be connected to an appropriate ground plate using a 3.31 mm² (12 AWG) copper wire, which is not included. The wire must be routed to a ground plate location and to the radar pedestal. Connect the wire to the ground connector on the pedestal using the pre-installed crimp connector. After connection, coat the ground screw and crimp connector with marine sealant to ensure waterproofing.

No, a voltage converter is not always necessary. Some radar models can be connected directly to the boat's battery (10 to 32 Vdc) via a 15 A inline fuse holder. However, if your model was supplied with a voltage converter, you must install it for the radar to operate correctly. Using a voltage converter with certain models that do not require one can improve resistance to strong winds. If a converter is used, it requires an input voltage of 10 to 32 Vdc and must be connected to the battery via an additional 30 A fuse (included with the converter).

Torque specifications are critical for secure mounting:

To secure the pedestal to the mounting surface, tighten the hex nuts to 14.7 N·m (11 lbf·ft). To secure the antenna to the pedestal, tighten the captive hex bolts under the antenna arm to 7.9 N·m (6 lbf·ft). It is essential to adhere to these values to prevent damage to the radar or mounting hardware.

Yes, opening the device may cause bodily injury and/or damage to the unit. This device contains no user-serviceable parts and should only be opened by a Garmin authorized service technician. Any damage resulting from opening the unit by someone other than a Garmin authorized service technician will not be covered by the Garmin warranty.

When connecting the power cable, it is imperative not to remove the inline fuse holder. To prevent any risk of injury or product damage caused by fire or overheating, the correct fuse (15 A for the radar power cable, and an additional 30 A if a voltage converter is used) must be installed as specified in the product documentation. Connecting the power cable without the correct fuse voids the product warranty.

To install the radar pedestal, you will need the following tools:

A Phillips screwdriver size #2A 6 mm Allen 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 wrench12 AWG (3.31 mm²) copper wire for grounding the radar housing and voltage converter (if applicable), length depending on the distance between the radar and groundMarine sealant

When choosing the mounting location, it is crucial to consider the following points:

The radar must be mounted out of reach of people, with the vertical beam width above head height. It must be mounted high above the vessel's keel line, with minimal obstruction of the radar beam. The mounting surface must be flat, parallel to the vessel's waterline, and sufficiently robust to support the radar's weight. The radar must be mounted where it can be connected to power, ground, and the network. The radar beam extends vertically 11.5° above and 11.5° below the radar's radiating element. It must be kept away from heat sources (exhausts, lights) and mounted at a different level from horizontal spreaders and mast crossarms. Keep it away from a magnetic compass (safety distance specified in the product specifications). Other electronic equipment and cables must be more than 2 m (6.5 ft) from the radar beam path. GPS antennas must be either above or below the radar beam path. The radar must be mounted at least 1 m (40 in) from any transmitting equipment and cables carrying radio signals (VHF radios, antennas). It must be at least 2 m (6.5 ft) from SSB radios (single sideband).

To prepare the mounting surface:

Secure the provided mounting template to the surface at the chosen location, aligning it along the bow-stern axis.Drill mounting holes using a 15 mm (19/32 in) bit.If you need to route power and network cables through the mounting surface, select a location along the central channel indicated on the template, drill a 32 mm (1 1/4 in) cable pass-through hole, and route the cables (optional).Remove the mounting template from the surface.

After positioning the pedestal on the mounting surface and inserting the threaded rods, tighten the hex nuts to a torque of 14.7 N·m (11 lbf·ft). This ensures a secure fixation of the radar without damaging the device or the mounting hardware.

Once the pedestal is securely mounted, follow these steps to install the antenna:

Remove the protective cover from the waveguide located on top of the pedestal. Align the pedestal’s waveguide with the socket under the antenna, then slide the antenna onto the pedestal. Secure the antenna to the pedestal by tightening the captive hex bolts located under the antenna arm. Tighten the hex bolts to a torque of 7.9 N·m (6 lbf·ft) to secure the antenna without damaging it or the mounting hardware.

When routing cables, it is important to:

Apply marine sealant around every penetration after cables are installed to ensure perfect watertightness.Use appropriate cable ties, fasteners, and sealant to secure the cable along its path and through bulkheads or the deck.Avoid running cables near moving objects, high-heat sources, or through doors and lockers.To prevent interference with other equipment, do not route network and power cables parallel to other cables (radio antenna lines or power cables). If unavoidable, cables must be shielded with a metal conduit or some form of EMI shielding.Install the power cable as close as possible to the battery source.

No. It is imperative not to reuse voltage converters from older Garmin radar models or third-party voltage converters. Using any converter other than the one supplied with the radar, or a correct converter purchased from Garmin or an authorized Garmin dealer, may damage the radar or prevent it from powering on correctly.

The GMR Fantom 254/256 radar power converter requires an input voltage of 10 to 32 Vdc.

When the radar is connected via a voltage converter, two fuses are required:

A 15 A inline fuse holder is included in the radar’s power cable and must not be removed. A 30 A fuse holder must be installed between the voltage converter and the boat’s battery. Both fuses must be in place for the radar to operate correctly.

The radar (and the voltage converter, if applicable) must be connected to a proper seawater ground using a 3.31 mm² (12 AWG) copper wire. This wire is not included with the product. You must route this wire to the seawater ground location and to the radar pedestal, connect it to the ground connector on the pedestal, then coat the ground screw and crimp connector with marine sealant.

The product warranty may be voided if the power cable is connected without the appropriate inline fuse holder. It is essential not to remove the 15 A inline fuse holder included in the radar's power cable.