Focus on the pronunciation of radar
English definition of “radar”
/ˈreɪdɑːr/ noun [C]
below/under the radar (also below/under the radar screen) › if something is below or under the radar, people are not aware of it: They were operating under the radar, selling their Web wares from some garage in Bakersfield. Many private treatment centres are slipping under the radar screen of the medical authorities.
on/off the radar (also on/off the radar screen) › used to say that people do or do not know about something or that something is or is not important to someone: He dropped off the political radar for nearly two decades. Toy safety is definitely on consumers' radar.