Garmin GMR™ 18 xHD3 radom

The Garmin GMR 18 xHD3 radome is a compact and high-performance radar solution designed for reliable detection and seamless integration with Garmin navigation systems. It features xHD3 technology, delivering significant improvements over previous generations, including optimized signal processing for better target separation and enhanced radar image clarity.

Key features include:

A vertical beam width of 25 degrees (12.5 degrees above and 12.5 degrees below the radiating element), ensuring effective coverage even in rough sea conditions.A compact 18-inch form factor, ideal for mid-sized boats where space is a critical factor.Optimized electromagnetic energy emission for precise performance, making it perfect for coastal navigation, precipitation detection, and collision avoidance.

For optimal performance and safety, several factors must be considered when choosing the mounting location:

The radar must be mounted out of reach of people, with the vertical beam width above head height. It should be installed high above the vessel's keel line, with minimal obstructions between the vessel and the radar beam. The mounting surface must be flat, parallel to the vessel's waterline, and sufficiently robust to support the radar's weight. Avoid mounting the radar near heat sources (exhausts, lights), other electronic equipment, or cables carrying radio signals. GPS antennas must be positioned above or below the radar beam path. The radar must be mounted at least 1 meter (40 inches) from any transmission equipment and radio cables, and at least 2 meters (6.5 feet) from HF radios (SSB).

Yes, the GMR 18 xHD3 radome uses Garmin BlueNet™ network technology and is compatible with Garmin BlueNet devices as well as Garmin Marine Network devices.

For a Garmin BlueNet chartplotter or a Garmin BlueNet 20 switch: Connect the radome directly to an open network port using the included Garmin BlueNet cable.

To install the GMR 18 xHD3 radome, you will need the following tools:

A drillA 9.5 mm (3/8 in) drill bitA 32 mm (1 1/4 in) drill bit (optional, for cable routing)A 4 mm (5/32 in) hex keyA 13 mm (1/2 in) wrench and a torque wrenchMarine sealant

Yes, the GMR 18 xHD3 radome can be installed on a cabin roof or hard-top, but precautions must be taken to ensure optimal performance.

The radar beam is transmitted vertically at 12.5 degrees from the horizontal midline. Therefore, you must raise the dome using a suitable mast or structure so the beam clears the edge of the roof or hard-top. This prevents transmitted energy from being reflected or absorbed by the surface, which is especially important if the surface is metallic.

Yes, it is mandatory to update the software on your Garmin chartplotter when installing the GMR 18 xHD3 radome. This update ensures compatibility and optimal operation between the radar and your navigation system.

Yes, the GMR 18 xHD3 radome is supplied with a mounting template included. This template must be used to drill the four 9.5 mm (3/8 in) mounting holes if you are not installing the unit on a pre-drilled Garmin radar mount.

It is important to follow the template instructions precisely to ensure correct dimensions and avoid damaging your boat’s mounting surface.

The Garmin GMR 18 xHD3 radome stands out with significant improvements in signal processing. This technology enables better target separation and enhanced radar image clarity, delivering optimized performance compared to previous generations.

The GMR 18 xHD3 radome has a vertical beam width of 25 degrees. This includes 12.5 degrees above and 12.5 degrees below the radiating element, ensuring effective coverage even in swell conditions.

The Garmin GMR 18 xHD3 radome is ideally suited to mid-sized boats. Its compact 18-inch format makes it particularly suitable for vessels where space is a critical factor, while delivering the benefits of xHD3 processing for coastal navigation, precipitation detection, and collision avoidance.

To install the GMR 18 xHD3 radome, you will need the following tools:

A drillA 9.5 mm (3/8 in) drill bitA 32 mm (1 1/4 in) drill bit (optional)A 4 mm (5/32 in) Allen keyA 13 mm (1/2 in) wrench and a torque wrenchMarine sealant

For optimal performance, the GMR 18 xHD3 radar must be installed with several considerations in mind:

It must be mounted out of reach of people, with the vertical beam above head height. The installation should be high above the vessel’s keel line, with minimal obstructions between the vessel and the radar beam. The mounting surface must be flat, parallel to the waterline, and sufficiently robust to support the radar’s weight. Avoid mounting it near heat sources (exhausts, lights), spreaders, or mast rigging.

To avoid interference, follow these recommendations:

Mount the radar at least 1 m (40 in) away from any transmitting equipment.Keep the radar at least 1 m (40 in) away from cables carrying radio signals, such as VHF radio and their antennas.Maintain a distance of at least 2 m (6.5 ft) between the radar and SSB radios.Other electronic devices and cables must be mounted more than 2 m (6.5 ft) from the radar beam path.GPS antennas must be positioned either above or below the radar beam path.

Yes, the GMR 18 xHD3 radar can be installed on the roof of a cabin or a hard top. However, it is recommended to use a raised platform or an appropriate structure to elevate the installation height. This helps prevent the roof from interfering with the radar signal, especially if the surface is metallic, and ensures the radar beam (which extends 12.5 degrees from the horizontal midline) clears the edge of the roof.

To calculate the required mounting height on a roof or hardtop, use the following equation:

(Distance (mm) × 0.222) - 150 = height (mm)

Or in inches:

(Distance (in) × 0.222) - 6 = height (in)

The 'Distance' refers to the measurement from the planned mounting location to the farthest forward corner of a rectangular roof, or to the forward apex of a curved roof. Then install a riser or bracket so that the radar base is equal to or higher than the calculated height.

For the power wiring, it is recommended to connect the cable directly to the battery. Do not remove the inline fuse holder, as the appropriate fuse must be in place to prevent any risk of injury or damage to the product. If an extension of the power cable is necessary, use the appropriate wire gauge based on the length of the extension to ensure sufficient power transmission:

2 m (6.5 ft): 16 AWG (1.31 mm²)4 m (13 ft): 14 AWG (2.08 mm²)6 m (19.5 ft): 12 AWG (3.31 mm²)

Yes, it is mandatory to update the software of your Garmin chartplotter when you install the GMR 18 xHD3 radome. For detailed instructions on the software update, refer to your chartplotter’s user manual.

The GMR 18 xHD3 radome uses Garmin BlueNet™ network technology and is compatible with Garmin BlueNet devices as well as Garmin Marine Network devices. For optimal performance and better support for future updates, it is recommended to connect it to the Garmin BlueNet side of your network when possible.

If your boat is equipped only with Garmin Marine Network devices, you will need a Garmin Marine Network adapter cable to connect the GMR 18 xHD3 radome to your network. The part number for this adapter cable is 010-12531-01 and it can be purchased separately if not included with the product.

Yes, to achieve the best possible performance and to avoid potential damage to the unit or your vessel, installation by a qualified marine installer is strongly recommended.