To give some more details, as I think not only it disconnect, but only the signal is weak. In my setup, the Internet box (802.11n, it's Freefox mini 4K if you are curious) and router C3150 are next...

Oh they somehow reopen this forum. I wish I whould have read all this a year ago. I have the same issue, some random drop of 2,4 GHz, then 5 GHz Wi-Fi. Acceptable at the beginning, then it became...