Consumer Reports, the influential product ratings magazine, gave a negative review of Apple's new iPhone. The assessment, which the publication attributes to a "design flaw" that causes reception problems, rejects Apple's earlier claim that the problem was due to erroneous formulas for calculating signal strength.

"Our findings call into question the recent claim by Apple that the iPhone 4's signal-strength issues were largely an optical illusion caused by faulty software," the magazine said.

The publication says that it tested three iPhone 4s. It subjected the iPhone 4s, and a number of other phones that include an earlier iPhone model, to the same conditions.

"None of those phones had the signal-loss problems of the iPhone 4," the magazine said.

Consumer Reports adds that holding the phone a certain way may decrease signal strength significantly. "When your finger or hand touches a spot on the phone's lower left side -- an easy thing, especially for lefties -- the signal can significantly degrade enough to cause you to lose your connection altogether if you're in an area with a weak signal," the publication said. "Due to this problem, we can't recommend the iPhone 4."

Nonetheless, Consumer Reports offers "an affordable solution for suffering iPhone 4 users: Cover the antenna gap with a piece of duct tape or another thick, non-conductive material."