Speaking of the unit’s sonar channels, it only has two, one for 2D and one for DownVision, using a CHIRP pulse modulation between 170-230 kHz for 2D, and 320-380 kHz for DV. Evidently, it covers both sonar channels supported by the unit, 2D and DownVision, and does work with the unit’s CHIRP sonar technology. This transducer uses a conical sonar beam for the 2D standard CHIRP sonar, featuring a 25° angle, while for DownVision it scans using a razor-thin beam, 1.4° wide in fore-to-aft, but 60° side-to-side.
#C MAP CHARTS FOR GARMIN 74DV SERIES#
Similar to the other Raymarine a Series MFDs, the Raymarine a78 is one of the retired units.