"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," said Mike Gikas, the publication's senior electronics editor in a blog post Monday.
Consumer Reports non-recommendation -- "Due to this problem, we can't recommend the iPhone 4," Gikas said -- is the latest in a series of knocks against the iPhone 4 over reception problems.
Complaints from consumers about the iPhone 4 dropping calls surfaced within hours of the smartphone 's launch last month. Apple quickly acknowledged that holding the iPhone 4 can diminish the signal but offered only generic advice, telling users to "avoid gripping it in the lower left corner" or "use one of the many available cases."
A week later, Apple admitted that the iPhone 4's signal strength formula was flawed and promised to update the software.
Consumer Reports's Gikas dismissed that explanation as a red herring. "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," he said.
The magazine tested three iPhone 4s in its radio frequency (RF) isolation chamber, where a cell tower emulator was used to simulate real-world signals. Gikas said that the publication's engineers also tested several other AT&T phones in the chamber, including the iPhone 3GS and the Palm Pre. "None of those phones had the signal-loss problems of the iPhone 4," he said.
Gikas said that the tests hinted that "AT&T's network might not be the primary suspect" in the iPhone 4 woes, quashing talk by some that the U.S. carrier is largely at fault.
"Consumer Reports carries some weight," said Jack Gold, an analyst at J. Gold Associates. "But I'm not sure how many people are actually reading it. Certainly, not many 20-somethings are."
Still, the magazine's testing and conclusion is bad for Apple on several levels. "This is a black eye for Apple," Gold said. "Now people can say, 'See, we told you it has reception problems.'"
Gold speculated that the antenna issue either escaped Apple's notice, or that the company knew of it and still released the iPhone 4. "This is basic cell phone 101," he said, referring to testing Apple should have done prior to launching the smartphone. "RF [radio frequency] is a sort of like black magic, so in order to make sure [handsets] work, cell phone makers have beta devices in the real world running around." But Apple, with its fondness for security, may have skimped on that part of its pre-release testing.
Consumer Reports also concluded that covering the antenna gap -- the small scores in the steel band near the bottom of each side of the iPhone 4 -- with duct tape or another thick, non-conductive material helps reduce the reception problem. "It may not be pretty, but it works," said Gikas.
That advice contradicts an antenna engineer's take two weeks ago that suggestions to tape over the gaps were just "hokum."
Consumer Reports continued to recommend 2009's iPhone 3GS. Last year's model is priced at $99 in an 8GB configuration, and is available at Apple's and AT&T's online stores.
"To me, [the reception issues] are fundamental problems that show Apple didn't properly test the iPhone 4," said Gold. "And I'm not so sure that the software update will fix it."