Apple has posted an open letter addressing the widely reported issues surrounding iPhone 4 antenna reception -- how it drops or loses signal when held in such a way that the lower left side is covered.
Short version is, Apple's claiming they are, and historically have been, miscalculating how they display signal strength as bars on iPhone. They repeat that all phones will drop some signal when held in certain place, Nokia, Android, BlackBerry, and iPhone alike, but because of the way Apple was displaying signal strength, the drop appeared far more dramatic on iPhone 4.
For example, if the signal drops two bars when you hold it, and you only really have two bars, you'd see no signal and understand the drop. If you have two bars but Apple is showing you 5 bars, and weighting the calculation far too heavily towards high bars, you could drop 2 bars and really have 0, but iPhone is still showing you 3, 4, or even 5 bars. There in lies epic frustrati
A software update, to be issues within a few weeks, will change the calculation to AT&T's recommended method, and Apple will make the lower signal bars easier to see at the same time. So, in other words, your signal will still drop but it won't look to be as good before it does so.
Apple also reiterates that both they and their customers continue to report that iPhone 4 has better than any previous model, and remind everyone that anyone unsatisfied can return an undamaged iPhone 4 for a refund within 30 days.
While this does seem to address the miss-reporting of signal strength Anandtech found in their tests, and acknowledging that iPhone 4 does get better reception and does drop fewer calls -- when it works -- it doesn't seem to address the higher levels of attenuation seen in raw signals, or some reports that the baseband software wasn't properly adjusting when that attenuation occurred.
A few weeks seems like a long time to push out an iOS 4.0.1 update just to fix signal bar strength reporting, so either Apple is just waiting until their usual late July window for their first update or are working on other bug fixes -- related to the antenna or other issues like the proximity sensor -- we'll have to wait and see.
Full letter after the break.