Hi all, I have a problem with my iPhone 4 dropping calls.the problem is that I can be mid way through a call when it drops out. Either the person at the other end goes quiet or I go quiet to them and I have to end the call. The call does not just hang itself up. When this happens I have had a look at the bars on the display to find that they're full. Also I hold the phone on my right hand and make sure not to cover the area affected by the death grip. This is a major issue for me. Does any one else have this issue before I return it to Apple for a replacement?