Raymarine’s Magnum high-performance magnetron radar in the 4-kilowatt configuration with 4-foot open array. 72-nautical-mile range, MARPA target tracking, Bird Mode out to 10nm, beam sharpening that drops the effective beamwidth from a 1.85-degree native to better than 1 degree. Sized for coastal and inshore cruising on Raymarine Axiom helms.
The Raymarine Magnum 4kW Radar with 4-foot Open Array and 15M RayNet Cable (MPN T70408) is the flagship configuration of Raymarine’s Magnum high-performance open-array radar line. The package combines the 4-kilowatt magnetron pedestal, the 4-foot open-array antenna, and the 15-meter RayNet cable for the mast-to-helm run. For blue-water vessels that need maximum-range detection, the Magnum 4kW with 4-foot antenna delivers the combination of raw power and antenna geometry that’s operationally required.
What 4 kilowatts of magnetron delivers. Output power directly determines maximum detection range, signal-to-noise performance through heavy weather, and the ability to resolve small targets at distances where they matter for collision avoidance and weather routing. The Magnum 4kW reaches up to 72-nautical-mile maximum range, which puts it at the top of the Magnum line and at the upper limit of recreational/cruising radar capability. For blue-water and offshore operation where you need to see weather systems and traffic at the longest ranges, 4kW magnetron is the right power class.
Why magnetron for blue water. Magnetron radars deliver peak transmit power that solid-state alternatives at recreational power levels cannot match. For long-range detection of distant weather formations, small offshore targets at extreme distances, and traffic visibility in heavy weather where lower-power radars wash out, magnetron’s raw power is what gets the operational job done. The trade-offs (warm-up time, higher standby load, periodic magnetron service) are acceptable for vessels that prioritize range capability over instant-on convenience.
4-foot open array. Antenna size determines beamwidth, and beamwidth determines target separation. The 4-foot Magnum array combined with Raymarine’s beam sharpening technology delivers better than 1-degree bearing resolution, which means two targets at slightly different bearings get resolved as two distinct returns rather than merging into one blob. For coastal navigation, commercial-traffic operation, and detailed map-like radar imaging of shoreline features, the 4-foot is the antenna size that justifies the open-array architecture over dome and shorter-array options.
Superior Bird Mode. Raymarine’s Bird Mode locates flocks of sea birds working bait out to 10 nautical miles. For offshore sport-fishing operations where bird sightings are the lead indicator for finding bait balls and fish, Bird Mode turns the radar from a navigation instrument into a fishing tool. The 10nm range means you can search a much larger area for bird activity than visual observation alone allows, reducing fuel consumption and trip time finding productive water.
Beam sharpening for better than 1-degree bearing resolution. Raymarine’s beam sharpening processing tightens the effective antenna beamwidth electronically, delivering target separation that the physical antenna alone wouldn’t achieve. The result is map-like coastal radar imaging, distinct target returns for boats in close proximity, and superior long-range performance where bearing accuracy matters most for collision avoidance and navigation.
MARPA target tracking. Mini Automatic Radar Plotting Aid (MARPA) provides automatic target acquisition and tracking through the Axiom display. Each tracked target gets course, speed, and CPA (Closest Point of Approach) calculations, so you know which targets matter and which don’t. Combined with Raymarine’s Evolution 9-axis heading sensor technology, Magnum delivers real-time accurate target plots that don’t drift with vessel motion the way less sophisticated systems do.
True Trails. Historical target trails are displayed with ground-referenced motion removed, so moving targets stand out from stationary returns even when your own boat is moving. For collision avoidance in busy waters, True Trails make moving boats visually distinct from buoys, shorelines, and reflections without the operator having to mentally compensate for own-vessel motion.
Integration with Raymarine MFDs. The Magnum 4kW connects via RayNet to current Raymarine Axiom and Axiom Pro multifunction displays running LightHouse 3. Backward compatibility with legacy LightHouse 2-based a, c, e, eS, and gS-Series MFDs, plus C-Series and E-Series Widescreen, E-Series Classic, and G-Series displays (note that not all Magnum features are available on all legacy MFDs). For boats refitting an older Raymarine helm or building a current Axiom-based glass bridge, the Magnum is the radar that ties cleanly into both.
Install considerations. The 4-foot open array and 4kW pedestal require structural mounting on a mast, radar arch, or hardtop with adequate support for the antenna assembly, rotating mass, and pedestal weight. The 15-meter RayNet cable routes between the mast and the below-deck network connection. Total install is a marine electronics installer day for a clean job, including mounting, cable routing, electrical integration, and chartplotter commissioning. Not casual DIY because the mast mount, cable runs, and Axiom calibration all benefit from professional setup.
Why pay this much. Three reasons. First, 4kW magnetron power delivers maximum range and weather penetration that lower-power magnetron and solid-state alternatives can’t match at this price tier. Second, the 4-foot open array with beam sharpening delivers target separation and bearing accuracy that smaller antennas and dome radars can’t achieve. Third, integration with Raymarine Axiom plus backward compatibility with legacy MFDs makes the Magnum a smart refit choice that doesn’t strand existing display investment. For owners running serious blue-water operations on Raymarine, the Magnum 4kW with 4-foot is the radar that earns its position.
