When was the first radar unit installed on the Roswell Army Air Field?

Question

Or when did the Roswell Army Air Field start using radar?
* Also, what was the average range of the radar sweep in miles?

Answer 1

July 1947

Answer 2

Was not the R:A:D:A :R: at Roswell an adaptation of Alien technology???

Of course it was, the British invented R:A:D:A:R: in W.W.2 and any none U.S. citizen is considered to be an Alien!! :-p