I had constant dropout which after the BT man visited were identified as no line fault or no broadband fault. Basically I had 1 minute of internet 5 minutes of internet and then 1 minute and so on. Sometimes I had no internet at all. I had this problem even with a wired connection so at first thought (and so did the technical specialists) that it had nothing to do with wireless. Anyway after 10 days, I switched off ALL my wireless devices and guess what the wired connection worked fine. I then changed my wifi channel (the MAC has an excellent built in scanner that helps you identify free channels see http://letstalk-tech.com/how-to-access-the-wifi-scanner-in-mac-os-x-yosemite/) and voila everything worked fine. Even the plusnet technical guys were flummoxed with it. It seems that if the standard plusnet router can't connect with a wifi device it 'gives up' on other devices as well whether direct cable or wifi. There may be other things that made were tried e.g cache clearing, DNS changes etc, but I got tried this solution and am sure it was the root cause. Anyway everything has been fine for 1 whole day now, so I am pretty sure this is the reason. I was told this should not happen, e.g a wired connection would always work even if wifi channels are noisy, but I am convinced this is not true. It cost me £20 of o2 data charges to keep the internet running at home (work from home often), so an expensive lesson. Hope this helps other!