Users who are and aren’t noticing the iPhone 4 signal drop problem might want to try taking their iPhone 4s outdoors, as well as inside different buildings. We’ve done quite a bit of testing with multiple units and found that the signal issue only is happening inside one specific testing location, doesn’t happen outdoors, and doesn’t happen inside at other places where we’ve tried it—but it does happen with multiple iPhones in the same place. It might be specific to a certain radio broadcasting frequency, or it could be due to interference from other wireless devices.