Got an iPhone 4 yet? Hold it carefully by the glass, avoiding the new steel antenna band that runs around the edges. Note the number of signal-strength bars you have. Now, touch the steel band with your other hand, preferably the left and bottom sides together. You will almost certainly see your signal disappear, or drop by three or four bars.

The problem is being so widely reported that Gizmodo has managed to add 16 videos of the phenomenon, along with many, many user reports. The problem is also repeatable, making it look like a lot more than simple coincidence.

Wired.com readers are also reporting the problem: Out of more than 40 respondents, about 35 are reporting a similar pattern of problems: If you hold the iPhone 4 in your left hand, or touch the lower-left corner of the outside steel band, the signal indicator starts losing bars within a few seconds. Many respondents indicated that this led to dropped calls, and one, "Edward," did download speed tests that showed a dramatic drop in throughput when holding the iPhone 4 in his hand, from 2Mbps to a measly 12Kbps.

Two respondents have said that they've observed the same diminishing-signal problem with previous models of the iPhone.

Two people have reported that keeping the iPhone 4 in its protective "bumper" case eliminates the problem, probably because it is an electrical insulator and prevents the antenna band from contacting the conductive surface of the skin.

If you have ever touched a bare-metal loop antenna for a TV, you'll know that the water-filled human body has an effect on the reception, although in that case it usually improves the picture. In this case, it has the opposite effect. It's possible that the antenna band is not a continuous loop, and that touching it in the lower-left corner short-circuits the loop somehow.

This, it turns out, is not entirely unexpected. Just two weeks ago, Jens Nielsen of Danish blog ComON quoted Professor Gert Frølund Pedersen of the Department of Electronic Systems at Aalborg University:

[H]uman tissues will in any case have an inhibitory effect on the antenna. Touch means that a larger portion of the antenna energy turns into heat and lost. This makes the antenna less efficient to send and receive radio signals. [Translation by Google]

Simply holding the new iPhone in the hand is enough to kill the signal. Even Walt Mossberg, in his review of the iPhone 4, had an eerily similar-sounding experience:

[O]n at least six occasions during my tests, the new iPhone was either reporting “no service” or searching for a network while the old one, held in my other hand, was showing at least a couple of bars. Neither Apple nor AT&T could explain this. [Emphasis added.]

Is it possible that a problem like this would make it into the wild? You'd think that it would have been discovered in testing. On the other hand, maybe this is what caused Steve Jobs' connection woes at the WWDC keynote where he demoed the new handset?

One possible answer is in the way the new antenna works. Instead of just picking the strongest signal, the iPhone 4 picks the highest quality signal, the frequency with the least amount of interference. In the current iPhone firmware, this is not yet reflected in the signal display, which still indicates actual strength. Apple has said that this is a known bug that it plans to fix. If true, then you shouldn't actually drop a call, even when your apparent signal-bars drop to zero.

Or perhaps it is all a sinister plot from Apple to sell more of those insulating rubber Bumper cases?

If you have an iPhone 4, please test this out for us, and post your experience in the comments. Specifically, check to see if a decrease in displayed bars corresponds with an actual drop in call quality.

Updated at 10am Pacific with reader reactions.

iPhone 4 Reception Issue? [MacRumors]

See Also: