below/under the radar(alsobelow/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(alsoon/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.