We have 2 x BT Infinity broadband supplies to our house, one downstairs for the family and one upstairs in my wifes office (Belkin router). My 2012 macbook pro always connects to the upstairs Belkin router, despite the fact that Im sitting with my macbook only 5 ft away from the downstairs Infinity router. It takes a couple of minutes before my macbook recognises the downstairs connection, and then I have to change to it manually. This is despite having set the downstairs connection to the top of the list in Wireless Network Preferences. I could delete the Belkin router from Network Preferences but its connected to a printer in my wifes upstairs office, which I occasionally need to use. Any suggestions on how to always connect to the downstairs router by default please?