I have setup an AC-68U as a repeater. Main router is an AC3100. I tried it first as a mesh system, but it kept disconnecting. It works quite well as a repeater. I have fixed channels on the main router (6 for 2ghz and 48 for 5ghz) but the repeater seems to be on channel 157 for 5ghz. I can't figure this out and I've redone it a couple of times. Does anyone know why it's not on 48?