For weeks,we've been hearing that the iPhone 4's reception degrades when users place their fingers in a sport on the phone's lower left side. Two weeks ago, Apple issued a statement on the matter, saying that all phones lose some reception when gripped in a certain way and that the only real problem was that the phone was showing too many bars in areas with poor reception. They promised a software update to make the signal strength reporting more accurate.
However, today, Consumer Reports said that its extensive laboratory tests prove that the iPhone 4's reception issues are very real and have nothing to do with the number of bars the phone is or isn't showing. For its tests, CR purchased three iPhone 4s and tested them in an isolation chamber that's free from outside radio signals, and connected only to a base station emulator that simulates AT&T's cell towers. For a control, they also tested several other AT&T phones including the iPhone 3GS and the the Palm Pre.
In CR's tests, gripping the iPhone 4 with one's finger over the antenna caused significant signal degradation, enough to drop calls. The other AT&T phones they tested didn't experience the same problem so it's clear that the iPhone 4's antenna -- not AT&T's network -- is to blame.
Because of the signal problem, Consumer Reports says they can't recommend the iPhone 4. However, if you already own one, they recommend placing duct tape over the antenna gap as that will prevent your fingers from interfering with the signal.
Read the whole Consumer Reports blog post for more.