GMR™ 24 xHD3 Radome

For optimal performance, the GMR 24 xHD3 radome must be mounted high, above the vessel’s keel line, with minimal obstructions to avoid shadow zones or false echoes. The higher the installation position, the farther the radome can detect targets.

The radar beam has a vertical dispersion of 12.5 degrees above and below the radiating element, requiring adequate installation height to clear structures such as cabin roofs. A mast or bracket may be necessary.

The radome must be kept away from heat sources (exhausts, lights), other electronic equipment (minimum 2 m), and magnetic compasses (a specific safety distance is required).

It must also be kept away from transmission equipment (minimum 1 m), cables carrying radio signals (VHF, antennas, minimum 1 m), and SSB radios (minimum 2 m).

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

The mounting surface must be flat, parallel to the vessel’s waterline, and sufficiently robust to support the radar’s weight.

The GMR 24 xHD3 radome uses Garmin BlueNet™ network technology and is compatible with Garmin BlueNet devices and Garmin Marine Network.

For a Garmin BlueNet network: Connect the GMR HD3/xHD3 to an open network port on your Garmin BlueNet chartplotter or Garmin BlueNet 20 switch using the included Garmin BlueNet cable. If your boat is equipped with a Garmin BlueNet chartplotter and uses a Garmin BlueNet 30 gateway to connect Garmin Marine Network devices, connect the GMR HD3/xHD3 to the BlueNet side of your network for optimal performance.

For a Garmin Marine Network only: You must use the Garmin Marine Network adapter cable (part number 010-12531-01, sold separately) to connect the GMR HD3/xHD3 to your network.

Ensure the locking collars on the connectors are tightened after plugging in the cables.

Yes, the Garmin GMR 24 xHD3 radome is compatible with Garmin Marine Network systems. However, if your boat is equipped solely with Garmin Marine Network devices, you will need a Garmin Marine Network adapter cable for the connection. This adapter cable (part number 010-12531-01) is not included in the product box and must be purchased separately.

When connecting the radome power cable, follow these precautions:

Do not remove the inline fuse holder. An appropriate fuse must be installed to prevent risk of injury or product damage from fire or overheating. Connect the red wire to the battery’s positive (+) terminal and the black wire to the battery’s negative (-) terminal. It is recommended to connect the power cable directly to the battery source. If an extension of the power cable is required, use the appropriate wire gauge for the extension length: 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) Incorrect cable extensions can cause radar malfunction due to insufficient power transmission.

No, the Garmin GMR 24 xHD3 radome must be used solely as a navigation aid. Using this device for applications requiring precise measurements, direction, distance, location, or topography may result in bodily injury or damage to the vessel.

Several actions can void the warranty of your Garmin GMR 24 xHD3 radome:

Connecting the power cable without the appropriate fuse in place. Opening the device by anyone other than a Garmin authorized service technician. This device contains no user-serviceable parts.

If you plan to install the radar on a roof or hard-top, mount it high enough to avoid interference with the surface. To determine the minimum mounting height, follow these steps:

Measure the distance from the planned mounting location to the farthest forward corner of a rectangular roof, or to the forward apex of a curved roof. Use the following equation to calculate the mounting height:

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

or

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

For example, if the mounting location is 2 m (2000 mm) from the roof corner, the mounting height would be: (2000 mm × 0.222) - 150 = 294 mm. Install a mast or other structure so that the radar’s base is equal to or higher than the calculated height. The beam transmitted by this radar extends vertically 12.5 degrees from the horizontal midline, so it is essential to elevate the dome so the beam clears the roof or hard-top edge.

The Garmin GMR 24 xHD3 radome is an advanced 24-inch marine radar system designed for demanding recreational boaters. It provides high-definition radar detection capabilities and optimized network integration, positioning itself as a high-performance solution for navigation, target detection, and safety at sea, thanks to Garmin’s latest signal processing technology advancements.

Main features of the Garmin GMR 24 xHD3 radome include:

High-definition radar detection.Optimized network integration.Advanced navigation and target detection capabilities.Use of Garmin’s latest signal processing advances for enhanced safety at sea.

For optimal performance and safety, the radome must be mounted:

Above the keel line of the vessel, with minimal obstructions to avoid shadow zones or false echoes.
On a flat and sturdy surface, parallel to the waterline of the vessel.
Away from heat sources (such as exhausts and lights).
Away from other electronic equipment (at least 2 m).
Away from magnetic compasses (the safety distance is specified in the product specifications).
Away from transmission equipment (at least 1 m) and cables carrying radio signals (at least 1 m).
GPS antennas must be either above or below the radar beam path.

Tools required for installing the GMR 24 xHD3 radome:

A drill. A 9.5 mm (3/8 in) drill bit. A 32 mm (1 1/4 in) drill bit (optional for cable routing). A 4 mm (5/32 in) Allen key. A 13 mm (1/2 in) wrench and a torque wrench. Marine sealant.

During installation, the radome must be positioned with the arrow on the underside aligned forward of the vessel. If you choose not to align the dome with the bow, you can adjust the boat's forward offset after installation.

For wiring and electrical connections:

32 mm (1 1/4 in) holes may be required for cable routing, and marine sealant must be applied to ensure waterproofing. Cables must not be routed near moving objects, high-heat sources, or through doors and lockers. Avoid running network and power cables parallel to other cables (radio antenna lines, power cables) to prevent interference. If unavoidable, cables must be shielded. The power cable should be installed as close as possible to the battery source. If an extension of the power cable is necessary, use the appropriate wire gauge based on the extension length. Do not remove the inline fuse holder. An appropriate fuse must be installed to prevent fire or overheating risks. Connect the red wire to the battery positive (+) terminal and the black wire to the negative (-) terminal.

The vertical beam spread of the GMR 24 xHD3 radar dome is 12.5 degrees above and 12.5 degrees below the radiating element. On vessels with higher bow angles at cruising speed, the installation angle can be lowered to direct the beam slightly downward toward the static waterline.

If the radome is installed on a hardtop or rigid roof, it must be mounted high enough to avoid interference from the surface. To determine the mounting height, use the following equation:

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

or

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

Where "Distance" is the measured distance between the intended mounting location and the farthest forward corner of a rectangular hardtop, or the forward apex of a curved hardtop. Then install a mast or other support so that the radar base is equal to or greater than the calculated height.

Yes, it is mandatory to update the software of your Garmin chartplotter when installing this radome. For update instructions, please refer to the user manual of your chartplotter at support.garmin.com.

The Garmin GMR 24 xHD3 radome uses Garmin BlueNet™ networking technology and is compatible with Garmin BlueNet devices as well as Garmin Marine Network devices. For optimal performance and to support future updates, it is recommended to connect the GMR HD3/xHD3 device to the Garmin BlueNet side of your network if possible.

If your boat is equipped solely with Garmin Marine Network devices, you must use a Garmin Marine Network adapter cable to connect the GMR 24 xHD3 radome to your network. The part number for this adapter cable is 010-12531-01.

The warranty for the Garmin GMR 24 xHD3 radome may be voided in the following cases:

Connecting the power cable without the appropriate fuse in place, as specified in the product documentation. Opening the unit by anyone other than a Garmin authorized service technician, as the unit contains no user-serviceable parts.

The radar transmits electromagnetic energy. To avoid potential bodily injury:

Ensure the radar is installed out of reach of people, with the vertical beam width above head height.Do not look directly at the antenna at close range while the radar is transmitting, as the eyes are the most sensitive part of the body to electromagnetic energy.Use this device solely as a navigation aid.Always wear safety glasses, hearing protection, and a dust mask when drilling, cutting, or sanding.