Definition
Radar return information that has been converted from its original analog signal form into digital values, allowing it to be stored, processed, transmitted, and displayed by computer-based systems used in air traffic control and weather services.
Plain English
Radar information that has been turned into computer data so it can be sent, stored, and shown on modern displays instead of just appearing as a glowing blip on an old-style radar screen.
Context Anchor
Seen in FAA acronym and notice material, and in discussions of radar information used by air traffic control systems.
Derivation
Digitized comes from digit, originally meaning a finger used for counting, later extended to numbers and then to data represented as discrete numerical values. Radar is itself an older acronym for radio detection and ranging. So RDAT literally describes radar information expressed as numbers a computer can work with.
Why Pilots Care
Almost every modern radar product a pilot sees, from ATC traffic displays to NEXRAD weather imagery in the cockpit, exists because raw radar returns were digitized first. Knowing the term helps when reading system descriptions, NOTAMs about radar outages, and references to data feeds in weather products.
Intuition Check
Do not read RDAT as a new kind of radar. It means radar information that has been converted into a form computers can use.
Example Sentence 1
The weather product on the cockpit display is built from RDAT supplied by ground-based weather radar sites.
Example Sentence 2
Older radar equipment produced analog signals, but newer installations send RDAT directly to digital screens.