For a long time, I had an Airport Extreme connected to a USB HDD (non-powered) that I used for Time Machine with no problems. A few days ago, I added a D-Link USB 4-port hub (powered) + my Drobo (powered). So now the setup is Airport Extreme + Powered hub + Powered Drobo + non-powered USB HDD. for some reason, the disks keep going into standby mode in this setup, regardless of the apps accessing them at the time. For example, i had iTunes and Google Music Manager running, actively uploading music, and the disks kept disconnecting. When I removed the USB hub from the equation and connected the Drobo directly to the Airport Express, the problem seems to have stopped (it has been working for a few hours now; before it would disconnect after a few minutes). So my question: what could be causing this? It's easy to say "it's the USB hub", but why? Could it be that the AE can't keep the disks active through the hub? Can you recommend a USB hub that won't let the disks go to sleep?