My daughters iphone 4 has had serious issue with detecting wifi networks for as long as I can remember. When the phone is near the router it can see and connect to the network but then drops out right away when you move it about 20 feet away, even in the same same room. Tried other router with no success as well as resetting the network settings. Wondering if this is a common problem. I am thinking of contacting apple before the applecare runs out.