The Marine Data MD71EMC is a complete, solid-state Electromagnetic Compass (EMC) Transmitting Heading Device (THD) system manufactured in the United Kingdom by Marine Data Systems Ltd.. Unlike Transmitting Magnetic Compass (TMC) systems that rely on a host ship’s mechanical magnetic compass card, the MD71EMC directly senses the Earth’s magnetic field using a solid-state fluxgate sensor with zero moving parts. It converts magnetic heading into digital NMEA 0183 serial data to drive remote heading repeaters, ECDIS, radar displays, and autopilots.

Engineered for vessels where installing a gyrocompass is physically impractical or cost-prohibitive, the system maintains accurate heading tracking at vessel speeds up to 70 knots and rates of turn up to 20° per second. The complete system consists of three primary modules: the MD53A/B Electromagnetic Fluxgate Sensor, the MD97CSP Compass Sensor Processor, and the MD71THD Control and Display Unit. It features automatic 390° swing calibration, magnetic deviation and variation correction, dual power inputs, and a high-contrast OLED interface.

Key Features:
• Solid-State Earth’s Field Sensing: Directly measures the Earth’s magnetic field without requiring a host magnetic compass or moving mechanical parts.
• High-Dynamic Tracking Performance: Maintains stable, accurate heading output at vessel speeds up to 70 knots and turn rates up to 20°/s.
• Automatic 390° Calibration: Built-in automatic calibration routine corrects magnetic deviation and variation effects caused by the vessel’s magnetic signature.
• Dual Redundant Power & NMEA Outputs: Equipped with dual 24V DC power inputs and two independent NMEA 0183 serial output channels ($HDT, $HDG, $HDM).
• Modular Three-Unit Architecture: Supplied with the MD53A/B sensor, MD97CSP processor, MD71THD display head, 10 m CAN Bus cable, and 2.5 m power/data cable.