I have a Mac Mini plugged into my TV, which also acts as a file and MP3 server, connected to my Airport network. Trouble is, if you don't use it for a while, it disconnects itself from the airport network. The airport network still appears in the airport menu and I can reconnect manually with no problems. I also have two other macs connected to the same network that never disconnect themselves. It's quite annoying because quite often when I want to access my files I have to go into another room and reconnect. Software updates are all bang up to date. Any ideas what could be causing this?