Apple antenna issue a 'physics problem,' not a software problem

Tech blog Anandtech goes hands-on with the iPhone 4, iPhone 3GS, and Nexus One to find out if the antenna issue is unique to the iPhone 4's hardware or software.

Erica Ogg Former Staff writer, CNET News
Erica Ogg is a CNET News reporter who covers Apple, HP, Dell, and other PC makers, as well as the consumer electronics industry. She's also one of the hosts of CNET News' Daily Podcast. In her non-work life, she's a history geek, a loyal Dodgers fan, and a mac-and-cheese connoisseur.
Erica Ogg
2 min read

Almost a week after the iPhone 4's launch, questions remain over why users experience signal loss when gripping the phone in a particular way.

Apple has called this a "non issue," despite users being able to repeatedly reproduce the problem. In the meantime, it's been suggested that it might be a problem that can be fixed with a software update. Others have said, and Apple has suggested, that users buy a case to prevent fingers from coming in direct contact with the antennas built into the metal band surrounding the iPhone 4.

The antenna being built into the iPhone 4's exterior casing is the reason for signal loss, and can't be fixed with a software update, Anandtech reports.
The antenna built into the iPhone 4's exterior casing is the reason for signal loss, and can't be fixed with a software update, Anandtech reports. James Martin/CNET

Brian Klug and Anand Shimpi at tech blog Anandtech have conducted their own hands-on experiments comparing different smartphones and their reception when the antennas are covered. They sum up their findings this way: "At the end of the day, Apple should add an insulative coating to the stainless steel band, or subsidize bumper cases. It's that simple."

The bumper case is a rubber holder that just surrounds the exterior of the device, and that Apple started selling the same day as the iPhone 4 for $29. Apple has already said it's not giving the cases away for free. It's not clear why the company wouldn't do that, especially when the problem has been reproduced by many people, though it varies by place and person.

At CNET, we were able to produce it, as have many users who've posted YouTube videos. But Klug and Shimpi have measured and recorded different ways of holding the iPhone 4 in various locations, the resulting signal drop, and compared it with the iPhone 3GS running iOS 4 and the Android-based Nexus One. They did the experiment six times with each phone and averaged the results for each device.

They conclude that Apple's design choice of putting the antenna directly into the metal band where a user normally holds the phone does improve signal strength. But when the user's hand cups the phone, the signal is markedly decreased. The signal is "very sensitive to direction, ambient conditions, and cell breathing," they write.

"The results are pretty self explanatory," they add. "Inside a case, the iPhone 4 performs slightly better than the Nexus One. However, attenuation gets measurably worse depending how you hold the phone. Squeezing it really tightly, you can drop as much as 24 dBm. Holding it naturally, I measured an average of 20 dBm."

It happens in most phones, as Apple said in its only official statement on the matter last week. But those other phones do not have the antenna built directly into the phone's case, and that doesn't mean the problem can be avoided, Klug and Shimpi conclude.

"There's nothing Apple nor anyone else can do to get around physics, plain and simple. It's something which demonstrably affects every phone's cellular reception."