Hello I currently have two Airport extremes (prior to the new revision) and one airport express. I am shortly moving to 50MB broadband in england and live in a house with rather thick old walls. I want to shift to the 5GHZ band for more speed.Currently I have my routers in B/G compatiable. I moved to 5GHZ and course it disconnected iphones etc but i managed stupidly fast broadband. I am thinking the best way of getting a multi cast new airport extreme into the network? Do i place the new one connected to a old one that is in "forced" 5GHZ mode or the other way around? (forced one being the old version that is by the modem) Currently if i shift them both to 5ghz , they extend 5ghz only, whereas i need iphone etc functionality returned.So im trying to connect the two in 5ghz only and then extending it by having mixed. make sense? Whereas now, the upstairs router, will only extend the network by 5ghz if the main router is on 5ghz.