At the bottom of my laptop list of networks is one called “hidden network”. The signal is stronger than my own routers. Its right next to me some where and it isnt mine. How can I physically locate it?
I’m just starting, so I don’t know if this will help, but I’m trying to do basically the same thing. In your situation, my thinking is to power things down one by one and watch for signal changes. I think I’d start with the breakers to narrow it down.
Could be a smart TV or similar item. Those sometimes have a hidden network for streaming (or for connectivity) and such. Any smart devices, pull the power plug from the wall and see if that hidden goes away.