Suspicious wifi location. Seems inside my place.

[Specifics]

I discovered on my list of wifi locations that there is one labelled "hidden network". It has a full strength signal. Even when my closest neighbor has their wifi on it is not at full strength when read from my location, so this is strange. Now when I turn my wifi off the signal strength of the "hidden network" goes down by more than half. This happens every time I turn off my wifi so there seems to be a correlation between my network and this network. It goes right back to full strength when I turn my router back on.
Another strange thing about the hidden network is that it appears at the very bottom of my list of networks available even when its reading at full strength.
I have had a suspicious login a while back so I have another reason to be suspicious of all of this. Just wanted to see what someone else thinks of all this. It seems as if the network is inside of my place until I turn my router off.
What is going on?

 

[pete.i]

I think it's something the idiots that write this coding stuff put in to baffle us. I have it on all my computers and always have for the last couple of years at least. I have tried to get rid of it and it isn't actually on my computer as such. It comes up in the list wi fi networks available.

And this......https://www.allthingssecured.com/tutorials/home-network/hidden-wifi-network-setup-tutorial/