My iPad can't connect on 4G in many locations where my iPhone 4 on 3G connects without a problem. My iPad does not "revert to 3G" it just continues to show 4G with no signal and I have to get out my iPhone to access data I need. I realize these are two distinct signals and wish I could turn 4G off or 3G on. I had my SIM card replaced just on the outside chance it was defective. What do you wise people think?