If you are new to using RADAR on board, take a look at our article How to Use a Boat RADAR.
Radar has always worked by broadcasting powerful microwaves and then receiving the echoes. Those echoes are then represented on an LCD screen. Radar on smaller vessels has historically required a considerable power supply with many using 2KW to transmit.
Digital radar works by transmitting long radiated signals using solid state equipment. This requires less power and can be processed digitally. With returning echoes varying in strength dependent on what they are bouncing off, being able to process the echoes helps improve the quality of the signal and its usability.
The digitized echoes can be represented on colour high definition screens. In these cases the reliability of the echo signal can be colour coded to help guide the user. Given the lack of moving parts, digital radar should become cheaper to buy, run and maintain over time.