Wifi killer

[dicko101]

Hi, my phone and everything else worked fine on my home wifi a couple of weeks ago, I got back home from a 10 day trip to Sydney yesterday, tried to watch a movie on Netflix on my chromecast to find that my phone was incredibly slow and the movie would never finish loading, tried my friends phone, same problem, eventually I worked out that her phone and my chromecast and everything else work fine as long as my phone is not connected, as soon as I connect my note 4 to the wifi, the whole lot slows to a crawl, I applied this fix http://forum.xda-developers.com/not...fi-channel-experimental-t3133527/post61307287 and the problem seems to have gone away, can you explain what's going on here? And is there a permanent fix? It's strange because I got 5.1 on my phone weeks ago and never had a problem. Any ideas?