Signal Academy is a primary combat school located on the island of Patch, just off the coast of Vale. Ruby Rose is a former student of Signal Academy, where she forged and learned to wield Crescent Rose, but was moved up two years due to an invitation to join Beacon Academy from the headmaster Ozpin.
Ruby and Yang Xiao Long's father, Taiyang Xiao Long is a teacher, and their uncle, Qrow Branwen, was a teacher at Signal Academy. At Signal, all students are required to craft their own weapons. Ruby is also the only known student in the series to attend Signal thus far; however combined with the fact that both her father and uncle taught there, it is likely that Yang also attended Signal.
In "Ruby Rose", when asked where she learned to fight the way she does, Ruby answers that she learned at Signal, surprising Ozpin with the skill she displayed with such a dangerous weapon. She then admits that her Uncle Qrow, a teacher at Signal, had actually taught her how to fight using her scythe. Later, when flying to Beacon Academy, Ruby says she can see Signal from the airship.
The night before the Beacon Academy Initiation, Ruby writes a letter to her friends back at Signal in order to tell them what Beacon is like. Yang Xiao Long teases her a bit, but Ruby objects by noting she didn't get to bring her friends when she left Signal and how it was odd to not have anyone else with her that she knows at Beacon.
In "Players and Pieces", near the end of the episode, Roman overlooks a map of Vale. Off the west coast, Patch, the island on which Signal is located, has been marked.