Rogue Signals is a side mission in The Evil Within 2. It becomes available at the start of the chapter 3. The mission will send you to follow signal from Mobius security team members who were talking about weapons caches. After completing the mission you’ll unlock Backup Ain’t Coming trophy / achievement.
Rogue Signals side quest is given to you by O’Neal. You’ll find him in the Safe House at the beginning of the chapter 3. When you start the conversation with him, choose the dialog option Supplies. O’Neil will tell you about signal and mark the signal locations on your Communicator. It’s not a dangerous mission, and all you have to do is to follow the signal throughout the map. The mission markers are visible on the map and it’s not hard to track down the signal. Once you investigate all places report back to O’Neil and complete the mission. During the mission you’ll unlock 4 Residual Memories and one File. After completing the mission Backup Ain’t Coming Trophy / Achievement will be earned.