A career in politics wasn't even 'on my radar (screen)' at that point. [=I wasn't thinking at all about a career in politics]
an actor who has 'fallen off the radar' [=who has stopped being noticed or talked about]
He tried to stay 'under the radar' [='unnoticed'] as he went about his business.
(..) And my advice is... Come on, already. Mike left one step ahead of the boys in blue, and you better believe his family's on the radar. A couple million bucks shows up, they're gonna snatch it The feds have already taken Kaylee's money twice. (..)2013 TvShow: Breaking Bad Title: Blood Money Season: 5 Episode 9