Furuno TZT and radar architecture

Furuno's NavNet TZ Touch series (TZT2, TZT3, TZT9F/12F/16F/22F) is the sportfishing and commercial workhorse. Backbone: NMEA 2000 for sensor data (heading, wind, engine data), plus Furuno's proprietary CAN network for the radar, sonar, and camera. Radar options: DRS4DL+ (dome, 4 kW, 24 rpm) for cruisers, DRS12A/25A (open-array, 12/25 kW, up to 48 rpm) for offshore. Rule for radar sizing: peak power determines maximum range in rain and clutter, not on-paper max range. A 4 kW dome shows 24 nm in good weather but 8 nm in real rain; a 25 kW open-array holds targets at 24 nm in the same rain. Antenna height matters more than power for close-in resolution: 1.5 m for a 2 ft dome, 3 m for a 6 ft open-array. Common issues: (1) Chart not showing, TimeZero chart card in the wrong slot or unsupported region. (2) Radar shows echoes at wrong bearing, heading input wrong (autopilot not sending, or offset in the setup). Recalibrate heading against a known bearing to a distant object. (3) NMEA 2000 backbone floods with errors, usually a device with a duplicate PGN address, or missing terminator. Furuno units follow the standard NMEA 2000 backbone rules (100 meter max, terminators at both ends, single power injection).