Does Poor iPhone 4 Design Cause Dropped Calls?

iphone4-antennas

 One of the featured tricks of the new iPhone 4 is that its metal frame actually forms the antenna system for calls and wireless connections. It's clever, but there are reports that holding the phone actually blocks the signals. What's going on?

The stories appeared over at MacRumors in the forums at first, and then were given more spotlighted attention over at Gizmodo, where it was reported that many people could reproduce the effects. What appears to be happening is that the iPhone 4 display shows more bars of signal strength when it's resting on a surface than when it's nestled in someone's grip. Some users report that the phone even drops calls when they're holding it and walking about, but not when it's in their pockets. Check out the video below to see the effect in action.

Though this looks bad, MacRumors wrote that other users reported they couldn't reproduce the effect at all. And then noted that by experimenting, some iPhone 4 owners who saw the signal degradation effects worked out it was only happening if you hold the phone covering the lower left corner of the device. Can a user's hand actually affect the iPhone's radio connection to the nearby cellphone tower?

sarThe answer is probably yes. But it's not necessarily for the reasons you may imagine, as radio frequency physics is trickier thing than it seems. All mobile phones will be affected when held in the hand becaue the body will attenuate the radio waves very slightly. Hence some people are concerned about mobile phone use and health--there would be utterly no reason for concern if the radio waves from the phone merely made their way unaffected through flesh (specifically, the head). But your body does absorb some of the energy. Besides raising possibly spurious health concerns, radio wave absorbtion affects how your phone can communicate with nearby cell phone towers, particularly in regions where the signal is already weak. 

The thing is, your hand is actually pretty radio-transparent, as it's full of gaps and isn't hugely dense--the radio waves from the antenna should be largely unaffected by a nearby limb. The difference with the iPhone 4 though is that you can actually touch the electrically-connected radio transmitting antennas themselves. You have to, really, if you're holding the phone. Is this going to affect how well they can transmit and receive radio signals? The answer is a definite "possibly." Because your body is weakly electrically conducting, and the interaction between your hand and the phone's metal antenna may indeed affect how it transmits radio waves. It's even possible that the lower-left corner sensitivity to being held is due to the user's hand weakly connecting the 3G antenna with the iPhone's other antennas, messing up the 3G signal transmission.

But it's hard to imagine this occurring as seriously as it appears in the videos--and Apple will have (don't doubt it for a minute) conducted extensive scientific and real-use tests on such a significant design feature. And with Cupertino's love of high-precision, it's unlikely they'd have let such a serious design flaw through. And from a raw physics point of view it doesn't really add up. 

So what is really going on, if anything? In regions where users have weak connectivity to nearby phone masts, it's plausible that signal attenuation from user's hands will affect signal strength to the point of affecting call quality. This really should be in the fringes of the signal from the antenna though--so maybe Apple's software is incorrectly displaying signal strength, and is actually overly-sensitive. Those users seeing three bars of strength drop to none may actually be equivalent to just one bar dropping away, in other words. We know that Apple's had software issues relating to the signal display systems before. With a patch (to tune the signal strength display to the particular performance of the iPhone 4) this will be less noticeable. It's also possible that some slight discrepancies in the manufacture of different iPhone 4s are affecting how sensitive to antenna interference each unit is. With the antenna exposed, this may be a more pronounced issue than in earlier designs.

And one last thing: Don't forget that this isn't necessarily a new effect. As MacRumors notes, similar effects have been demonstrated on earlier edition iPhones for years, and nobody's made much of a fuss about it. Gizmodo does, for one reason or another, have a bit of an axe to grind against Apple at the moment ...

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5 Comments

  • Zach

    I have the new iPhone, and I can definitely attest that it is as bad as the videos demonstrate. It IS possible that it only has a serious effect in areas of low signal strength.

    At both my work and home, I got about 2 bars of signal with my previous AT&T phone. With the iPhone 4 sitting on a table, it shows a consistent 4 or 5 bars. As soon as I bridge the gap between the metal plates on the lower left, it drops to one bar or "Searching for network".

    Even when it shows one bar, the data portion of the connection is completely cut off. I ran the Speedtest.net app 10 times in a row without touching the side, and it got between 600 to 2000kbps with a ping of 250-1200ms. Not great, but usable. When I tried it while touching the side at the gap, it would not pass the latency test at all - no connection whatsoever.

  • Ken

    Confirmed, this does actually happen.

    Happened to me last night, it appears to be temperature related. I had just finished transferring
    a bunch of music to new phone and went to use the phone and the bars dropped rather rapidly down to 1.

    The phone was fairly warm after doing all that music transferring. This morning it does not appear
    to be doing it and the phone is cool to the touch. Probably takes a prolonged amount of time for this to
    occur and only occurs when the phone has heated up.

  • Mo

    "Apple will have (don't doubt it for a minute) conducted extensive scientific and real-use tests on such a significant design feature"

    They tested it in a case to make the iPhone 4 look like an iPhone 3GS. So they wouldn't be able to get the exact same usage cases in the real-world.

  • Aaaarrggggg!

    I am curious if you could paint the metal antenna with clear nail polish - or better yet (and definitely the safer option, just buy the iPhone's rubber baby buggy bumper.

    Either way, this is a design failure. (I wonder if Steve Jobs let the designers actually hold the final device - especially after a prototype "escaped" from the lab.)

  • Chet Hammer

    You are dead wrong about the physics end of it. There is a reason that antennas used in electronic devices have been shielded for years and years, but I'll let an expert tell you better than I could. Apple needs to be held accountable with their failures as well as their successes. I own many apple products myself (ipod, ipod touch) and in the previous few weeks I've decided that I'm done with them. I'll no longer support The Hitler of the tech world any more. This quote is taken from an article by Jens Nielson.

    One of the leading experts when it comes to mobile phone antennas, is Professor Gert Frølund Pedersen from Aalborg University's Department of Electronic Systems.

    He is leading an international research team that recently got one million support from Advanced Technology Foundation to develop a more effective mobile antenna, and has for many years studereret antenna technology on the mobile front.

    Asked about Apple's iPhone presentation of four, he answered that the design of the antenna as a part of the phone's frame is an old news that is seen many times before. Virtually all cell phone antennas on the market uses phone's metal parts such as antenna.

    But on the iPhone 4, it also appears that this antenna's designs can provide special challenges because a portion of the antenna will inevitably be affected by the user's hand.

    'The actual circuit board works as a part of the antenna and the metal frame around the coupler signal into it. But it means that the user can not avoid interfering antenna system with its touch, "says Gert Frølund Pedersen ComON.

    Men kan designerne ikke kompensere for berøringen i software, sådan at de ophæves eller ligefrem bruges som en fordel? But designers can not compensate for touch in the software so that they are repealed or even used as an advantage?

    "But the human tissue will in any event, 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 transmit and receive radio signals, "says Gert Frølund Pedersen.

    Translation is that the human body is good at absorbing heat (we're mostly water). The rubber cover Apple is willing to sell you for $29 will alleviate this problem, not cure it. The device is still faulty.