channel 36 seems to be the only 5 Ghz that the note 2 works right on. My nexus 5 doesn't seem to care. If your using more than 1 AP then you want them all on the same channel and same ssid/password . People start having issues when they mix different gear into their wifi setup like this one. With the same gear, ssid, password things should work fine if your not running ontop of someone else. The cut off point of interference is around 60 dBm or lower. if your wifi is walking on the same channel with that much bleed over from someone else's wifi then you need to change channels. Kill the wideband and switch it back to 20. or simply go the 5Ghz route. As far as devices trying to to stay with the original AP while roaming that really only applies to different ssids which is the true meaning of roaming. Staying within your own ssid and same channel isn't really roaming even if your moving from one AP to the next inside your own wifi network layout.

Sent from my Nexus 5 using Tapatalk