Why am I experiencing Wi-Fi dropouts on Chromebook and Linux?

I am having a problem with Wi-Fi dropouts on both my Chromebook and my Linux computer (which are both less than a month old). I will be within about 6 feet of my (fairly new) XB8-T Xfinity router/wifi (with a direct line of sight), and it will just drop out. When I check my phone and my Android tablet, the Wi-Fi seems to still be working just fine with a strong signal. This is now happening several times per day. When I try to reconnect, my computer cannot find any Wi-Fi networks. I try turning Wi-Fi off on my computer and back on, but still no networks are found, so I am forced to restart my

Question by user36086 on Super User, licensed CC BY-SA. We show a short excerpt and link to the original thread as credit.