Experts Explain iPhone 4 Antenna Problem

CWmike writes "Reports of call and data signal strength problems in the new iPhone 4 have a basis in fact, a hardware expert said Thursday. Later in the day, Apple acknowledged that holding the iPhone 4 may result in a diminished signal that could make it difficult to make and maintain calls or retain a data connection. 'Gripping any phone will result in some attenuation of its antenna performance with certain places being worse than others depending on the placement of the antennas. This is a fact of life for every wireless phone,' Apple said in a statement issued to several media outlets, including PC Magazine, which had run tests earlier Thursday. 'If you ever experience this on your iPhone 4, avoid gripping it in the lower left corner in a way that covers both sides of the black strip in the metal band, or simply use one of many available cases.' Scores of new iPhone owners confirmed the reception problem in a string of more than 360 messages posted to a thread on Apple's iPhone 4 support forum." A blog post from an antenna design company explains that the reception problems are probably the direct result of phone design adapting to FCC requirements.

Comments

Cases

[Peach Rings]

How will wrapping the phone in a case and then holding it the same way as before fix the problem?

Re:Cases

[icebike]

Exactly.

Its not that the antenna is at the bottom, its because it is external, and metal, and skin is conductive.

This is a fundamental design flaw that I can't believe they let slip. Now they will probably have to offer discounts on "bumpers" to bring the phone back up to published specifications.

Using external antennas that can be shorted by normal hand moisture! I'm not aware of any other phone that does this. Why was it necessary with a glass backed case? The antenna could have been at the bottom like prior iphones.

There is SO Much about this iPhone release (hardware and software) that has been problematic that I am starting to believe Apple's claims that the leak of the "lost" phone was indeed damaging to Apple. I think it forced their hand, and cornered them into releasing a phone that was not yet ready with software that still had a lot of problems.
The fanboys will be here momentarily to mod this down. Sigh.

Re:Cases

[Gary W. Longsine]

I was initially skeptical that this might be software related, but recent rumors have a plausible software theory. The new iOS 4 has a new algorithm for picking the tower and channel that the phone uses, when it can see more than one. It appears that this mechanism may have a defect which is triggered by attenuating the signal (such as by bridging the two antennae with salty skin). This appears to cause the phone to decide to attempt switching channels. The speculation is that the timing is off, and the phone sometimes reports "no signal" rather than deciding to switch or stay put.

Death Grip hysteria may end Monday with iOS 4.01

The issue described is plausible, and fits some of the observations.

• Some folk can reproduce this problem, basically at will (one of the magazine review sites).
• Other folk are unable to reproduce this problem, at all (another reviewer at the NYT).
• At least some folk who can reproduce this issue are doing so in areas where reception was previously known to be marginal (including one of my developers at his house).
• The problem may have been harder to diagnose during Apple's testing, due to pre-release testing taking place inside insulated cases, thus the problem would be triggered less often, and not in associate with anything special that the user would notice (holding the phone in a certain way). The frequency of dropped calls might have been within the "normal" range for the AT&T network, given the small sample size of a few hundred test users. (Apple's off site testing includes hundreds of people, but that's actually a pretty small sample size, compared to the 600,000 people using the phone today.)

It will be interesting to see if a software patch emerges within a few days or even weeks, and cures this issue. If it does, I'll think back to several cell phones I had previously, which had problems that I could and did reproduce, and reported clearly to the vendors (both network and cell maker) and for which no patches were forthcoming, ever, during the life of the phone. Regular software updates for iPhone are a damn sight better than the old way, where the answer to any problem was "buy the new version of the phone you just bought a month ago".

Re:Cases

[cybereal]

The effect of attentuation drops off exponentially as you remove the attenuating obstruction from the antenna. However, there is reason to believe that there is a different problem besides attenuation affecting a very small number of handsets. Personally I suspect some kind of ground fault in the casing leading to a magnetic field interfering with the radio itself. This wouldn't demonstrate itself as the loss of a couple bars, it would be complete or nearly complete loss of signal.

That said, I have an iPhone 4 and cannot reproduce any of the reported problems at all no matter what I do. I have to put my phone in what almost amounts to a faraday cage (a steel lock box) just to see any signal degradation. But a friend of mine has seen the problem occur with nothing but the tip of his finger placed over the antenna on the left side, specifically when touching the metal. The metal plates are not the antenna, the black lines are, so what this tells me is that there is some issue with grounding of the body in that phone. But until I can have him try his "magic finger" on my own iPhone, I wouldn't jump to any real conclusions. None of the reports so far have been remotely scientific. There are numerous variables and without any cross checking it's all guesses for now. Attenuation will definitely occur but it's usually not so dramatic as to go from five bars to "Searching..." like this friend of mine is seeing.

Re:Cue the fanbois

[PolygamousRanchKid]

Next thing you know, holding a cell phone with the thumb and forefinger by the top right corner will become the fashionable way for any of the cognoscenti to hold their phones.

So how come this problem was not identified during the system test of the device? Were all the testers instructed to hold it that way? Or maybe they identified it, but did not have the courage to report it?

Danish professor predicted this

[Namarrgon]

This guy is an expert in antenna design from Aalborg University, and predicted this two weeks ago.

Re:form over function

[Luckyo]

Actually this was touted on iphone4 introduction speech as a "major new feature" by Jobs. It was kind of obvious for anyone who actually ever worked with antennas that it was trouble. But apparently it sounded fashionable to countless ears of apple clients.

It's a feature among others, aimed to increase hype value of the device. It's pretty obvious why no one else did it, and hence probably seemed like a good marketing idea to apple. All it had to do was what it always did, present it as an awesome revolutionary new feature.

Re:form over function

[MichaelSmith]

Maybe their validation staff have small fingers. More likely testing was done with the device flat on a bench with people checking boxes to verify correct display on the screen.

I see this all the time in my work. Our system just isn't used in the same way it is tested.

Re:Cue the fanbois

[Anonymous Coward]

So how come this problem was not identified during the system test of the device?

Because - you'll really love this - they put it in an iphone 3 case when they were supposed to be testing it so as to keep the super shiny design secret. Really. The product they were testing wasn't the product they were planning to launch. Bunch. Of. Cowboys.

Re:Cue the fanbois

[Dahamma]

Luckily the human body is a pretty poor conductor, as long as you are not standing in the shower (which I believe would be a bad place to talk on the phone anyway).

I can say from first hand testing that the initial quality of the signal has a lot to do with the attenuation caused by this issue - if you already have a good signal it doesn't seem to cause any problems.

Anyway, as you said, the fact that this was missed is pretty amazingly bad testing, especially considering how Jobs actually described in the keynote that the reason the metal on the outer rim had a visible break was because it acted as an antenna. Wouldn't you think the *first* question one would ask as a tester (or an engineer!) is "hmm, these are not connected for a reason - I wonder what happens when I connect them with various common household objects, like, say - my HAND?"

Re:The media need to call Apple out.

[Jarik C-Bol]

I enjoy many apple products. However, they do not shit rainbows and butterflies. I am aware that they, like every other company on the face of the planet, from time to time, produce an inferior product. Your welcome to your personal shit-fest about apple, but really, if your that butt hurt about the existence of the company, then go cry in a corner you emo prick.

I want you to consider how shitty the home computing world would be if Microsoft never had ANY market competition. Imagine for a second how shit-tacular whatever OS we would be using would be if there were no competition between Apple and Microsoft. They are polar opposites in many ways, and wether they admit it or not, they strive to out do one another in the OS department. Without competition, the OS world would be a disgusting wasteland.

Apple is damn sure not a golden god on a unicorn with butterfly wings like some idiots make them out to be, but your fanatical 'anti apple' stance is just as moronic. /rant goodbye karma....

Re:It may have been

[hobo sapiens]

"
And they would have been correct - they will sell more from looks and the Apple fans will not only hold it different or purchase the rubber pads but will sing the praises of having to do so.
"

I use a Macbook Pro as my development machine. I love that computer. It runs like a champ, is fast, battery life is great, and the trackpad is just about my favorite piece of computer hardware ever. It's great...except for the PERFECT right angle along the perimeter of the thing. A perfect right angle + solid aluminum construction = sore wrists for me.

I googled it to find out if I am alone in disliking the sharp edge along the perimeter of the thing. There were not just a few people touting this as A Good Thing, because after all everyone uses a computer in the same way and you are NOT supposed to rest your wrists on the mighty macbook after all, so Apple was just helping me to learn how to properly use a computer. An obvious design flaw justified away by so many people. I like my iPhone, I like my macbook, so I guess that makes me an Apple fan. But to justify design flaws, as though Apple were incapable of such a thing is inexcusable.