I will begin with a question: Q/ is .ac protocol more prone to dropping the internet connection than the slower .n protocol?
I ask as it seems to me it maybe.
Since I installed a new .ac router a few months back I have been afflicted with internet dropping, for some strange reason on Saturday mornings (?). Sometimes the only way I know (without switching on the computer), is because I have a Sky "On Demand" box that has two bright lights one is the internet connection, which will be off.
Usually all the relevant lights will be on on the router including the internet connection. I now check certain things before rebooting the router (which cures the problem). I have two printers, one will still be showing its blue wifi light, the other will be offline, needing (after router reboot) to have a search and router passcode. The same applies to the Sky on demand, also needing a search and passcode.
At the computer, which doesn't have an in built .ac adaptor (only .n), but is connected with a USB3 .ac adaptor dongle. The router is dual band and I can find it has switched between the .n and .ac is/are disconnected reporting "no internet", but usually restarts normally as the .ac it set to "connect automatically" on router reboot.
Having made all these perhaps unnecessary checks, I switch off the router, wait the "magic" twenty seconds and reboot. After several minutes all returns to normal, except for the printer and on demand box.
So I return to my OP question, or should I be suspicious of something else in the setup?
In all the years of using .n protocol, barring power cuts or deliberate shut downs I think I can safely say I never had the internet connection drop.
Experience; is something you gain, just after you needed it most.
When faced with two choices, simply toss a coin. It works not because it settles the question for you. But because in that brief moment while the coin is in the air. You suddenly know what you are hoping for.