back to article iPhone 'Death Grip' effect is real, plastic cases don't help

The so-called 'death grip' effect, in which a user's hand touching a smartphone antenna degrades its radio connections - a major issue for the iPhone 4 with its external antennae - is real and is a serious problem, according to British boffins researching the matter. Furthermore they found that plastic insulation between hand …


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  1. Ian Ferguson

    Why just blame the iPhone?

    I'm no Apple fanboi but surely these findings affects all phones, if making a connection between your hand and the antennae, even through a plastic barrier, degrades the signal.

    1. John Robson Silver badge

      Gap important

      Because I presume the distance is important - even an extra couple of mm can have a huge effect, most other phones bury their antenna a bit more deeply than the iPhone.

    2. dotdavid


      I'm a rabid Android fanboi, but even I admit that holding my Nexus One in certain places seems to have an effect on the signal.

      Maybe the "hand-making-a-bridge" problem was more noticable than the problem tested here though, which would explain why the bumper cases have helped.

    3. James Hughes 1

      In the article

      It mentioned that smartphones were bad, but when the antenna is actually touchable (i.e. iPhone) it's worse.

      At least that's how I read it.

      1. Jeremy Chappell


        Why does the iPhone 4 get a signal in places where my old Motorola didn't (just a week or so before)?

        The thing about the iPhone 4's antenna design is the "weak spot" is marked with other "traditional" designs there is a "weak spot" but it hasn't got a line showing you where it is!

        Now the iPhone 4's design isn't perfect, the thing is a bit "slippery", especially with glass on both back and front, but I don't think raw "network coverage" is really an issue - mine seems to find a signal in places where both Nokia and Motorola handsets didn't. Yes, we're talking about the same network.

        No I don't use a case with the iPhone 4, and it's just "stock" not modified or weird (or white!)

        What is really impressive is the battery life (for a smartphone). Putting the antenna assembly in the phone's main structural element does make room for a bigger battery.

        1. Naughtyhorse

          great idea

          so you can spend far more time when you cant make a call runiing all them there apps.

          it's a PHONE for fucks sake. that, under certain circumstances, cant make calls - due to crappy design. The words teapot and chocolate come to mind.

          having a biger battery is irelevant

  2. Reading Your E-mail

    To quote Snatch

    "Yeah Dad, you told us"

    His next project is finding a catholic in the Vatican.

    1. Dr. Mouse

      This is the first step

      This is the first step of such a project.

      It may be that the results don't come as a surprise, but in order to gauge the problem, you need to perform controlled, scientific tests.

      The next stage, which he has said he will be doing, is to find a way round the problem. This is much easier when you have accurate measurements to start with.

      1. tedl
        Paris Hilton


        You are assuming that Apple can not and has not already chosen the best compromise to deal with this? Apple just slapped an antenna on the outside then said "oh that's why nobody else does that". Apple thinks more than any other company about what makes a plesant experience for it's customers. This design isn't a "mistake". It's a carefully considered compromise between phone size and reception. Apple isn't perfect but they also aren't sloppy when it comes to product design.

        1. J 3


          "Apple isn't perfect but they also aren't sloppy when it comes to product design."

          I see you must not have used the new iPod nano (6th gen) for any length of time, then. That "hold" button is a disaster.

        2. Anonymous Coward
          Anonymous Coward

          U ASS

          "Apple isn't perfect but they also aren't sloppy when it comes to product design."

          As much as it amuses me to read the your wild speculations about Apple I must point out that the FACTS point to an altogether different conclusion.

      2. Mike Pellatt

        Hardly "original" research


        Scientific research to establish that the presence of a large conducting body near an antenna will detune it or cause it to be mismatched to the characteristic impedance of the feeder ???

        I think you might well find a large, if not massive, body of research showing this. Stretching back a good few decades, if not to the birth of RF Communications (well, post-spark transmitters anyways).

        This is why MIMO doesn't work as well as it might - one antenna impacts on the performance of the other.

        1. Steen Hive
          Thumb Up

          Re: Original

          "I think you might well find a large, if not massive,

          body of research showing this."

          Not to mention high-school physics. Fashion designers trumping engineers will always end in tears.

        2. Steven Knox
          Thumb Up

          Original Research

          The general principle is not what was researched here. What was researched here was the specific effect under specific conditions.

          We've known F=ma since before the invention of the automobile, but it wasn't until tests showed the results of application of that principle under highway collision conditions that auto manufacturers started thinking seriously about safety features.

      3. Anonymous Coward
        Anonymous Coward

        No, that can't be real! Somebody doing

        REAL science?!?!?!

        Stop the presses! Hell hath frozen over.

    2. The Cube

      That may be harder than you think

      As most of the actual Catholics are outside waiting to see the Pope. Those who have risen far enough up the power structure of the church to be in the Vatican in uniform on the other hand have got there not through being good Catholics but by being good politicians.

  3. Anonymous Coward
    Jobs Horns

    working on “automated re-tuning of the antenna elements"

    Why bother? let Apple fix it, it's their mess and they have much more money in the bank to pump into research

    1. RegisterThis

      Yeah ... I'm sure they will 'fix' it ...

      IF de-tuning detected THEN increase signal bars shown


  4. nichomach
    Jobs Horns


    ...measuring it wrong. Not that big of a deal.

  5. This post has been deleted by its author

  6. Anonymous Coward
    Jobs Halo

    The opposite is true - Im no Fanboi

    Past experienes with Portable radio suggest that touching the antennae improves the reception when signal is flaky. So why is it different here?

    1. Paul Crawford Silver badge

      @opposite is true

      There is no simple answer (as you might have guessed) as you have a number of conflicting aspects to antenna design.

      In general, if you are talking about an electrically small antenna (i.e. physically much less than 1/4 wavelength, etc) then you might find that adding your fleshy touch improves reception by adding to the area able to intercept signals.

      However, the converse aspect also applies (probably here), in order to make any antenna work efficiently they are normally in resonance (i.e. tuned to a specific narrow range of frequencies) and by touching them you de-tune them and so make the job of getting power in/out of them more difficult. In addition, the body is not a *good* conductor, so tends to make the thing lossy and not only to re-tune it to a different frequency.

      Over all I expect flesh decreases reception.

      The iPhone problem is certainly *not* unique, just that the close proximity of the antenna to the hand makes the effect significantly stronger, and on top you have Apple's attitude to the problem with their high-end device where style has prevailed over best-practice RF engineering.

      1. tedl

        Yeah that is it

        Apple put the antenna on the outside, did some minor testing and told Steve that there could be a reception problem. Then Steve said who cares it looks cool this way. Yeah I see that happening.

      2. Jeremy Chappell


        The conductivity of skin to stainless steel is so low it can be discounted. What is more likely is you're creating a capacitance, but any antenna reasonably close to a plastic case would have the same effect (and in fact this appears to be true as the issue isn't unique to the iPhone 4).

        Where the iPhone 4 is different is the spot where this is most likely to happen has a line across it. So if you want to demonstrate is then it's quite easy (cover the line with a finger). Conversely if you want to avoid the issue then don't put your fingers over the line (hence the much quoted; "you're holding it wrong"). However such spots exist on other phones too, they just aren't as clearly marked ;-)

      3. Tom 13

        The key bit being

        "...Apple's attitude to the problem with their high-end device where style has prevailed over best-practice RF engineering."

        If Apple had owned up to it whether saying it was a design flaw or a design decision, the flameage would not have been as intense. Granted saying design flaw would probably have been more expensive as people would then have expected them to FIX the design and retrofit it to all the devices already sold, but it would have reduced flameage.

    2. Elmer Phud


      I stil laugh at Jeremy Clarkson when he does the 'hold car key to head then open doors' thing on a much repeated Top Gear.

      Maybe the iPhone needs to be placed somewhere else?

      (ducks and runs)

    3. Terry Barnes


      Not spent any time in the field of RF design then?

      At some wavelengths and in certain circumstances touching an antenna can result in an increased ground plane effect which might improve reception.

      That's not true for UHF or microwave.

      The issue here is that the finger bridges two different antennas creating a new hybrid metal/person/metal antenna that is severely compromised for any of its intended uses.

  7. Anonymous Coward

    "Holding a phone degrades the signal"

    Wow, wouldn't have guessed. Holding ANY phone degrades the signal - I see it on my iphone 3gs + 4, also on my ancient nokia dumbphone and my wife's new nokia dumbphone.

    And the bumper: it's there to prevent the antenna bridging, and works brilliantly. With my iphone 4, I can kill the connection most of the time by holding it tightly. With a case, the effect is minimal (no worse than the other phones anyway).

    Can I get a large research grant for typing that please?

    1. Anonymous Coward
      Anonymous Coward

      Thinking you are clever is a symptom of stupidity.

      "no worse than the other phones anyway"

      You people keep saying that even though it is totally and utterly wrong.

      While all phones may have a reduced signal in certain circumstances, the iPhone 4 has a special, additional problem all of it's own. That is what this research is saying.

      No one is going to give a grant to person who has difficulty comprehending basic information.

      "And the bumper: it's there to prevent the antenna bridging"

      No. It's sold as insurance against the 4's well documented reception problems not specifically to prevent "antenna bridging". Look like it doesn't work.

  8. Gav

    unnatural laboratory situation

    "then with the antenna actually in contact with a "thumb phantom" with the same dielectric properties as human skin."

    So they didn't actually test it with an actual human thumb attached to an actual human person? How then can any reliable conclusions be reached? All they've demonstrated is antenna performance in an unnatural laboratory situation that assumes their replacement mimics all the variables of the real-life scenario.

    They can say that the "phantom thumb" mimics the human thumb, but without a comparison performed in the same experiment how do they know? It's an assumption that may not be true.

    1. Neil Milner-Harris


      Impressive selective reading there:

      "reduction in sensitivity of the device when held, or when the user’s thumb is mimicked by phantom material"

      1. John Bailey

        RDF induced fact blindness.

        It's quite a common ailment amongst fanboys.

        No doubt someone will also attempt to explain how holding the precious while using it with no measurement equipment other than the reception bars is far superior to controlled conditions in a lab performed by an expert in the field.

        Never mind guys.. Tell us again about the market cap..

        1. Getter lvl70 Druid

          "Holding The Precious"

          You owe me one, buddy!

        2. Anonymous Coward
          Anonymous Coward

          How do you know he's a fanboy?

          He might just be thick.

          1. Anonymous Coward
            Anonymous Coward

            Jus' sayin'

            'How do you know he's a fanboy?'

            'He might just be thick.'

            They aren't usually mutually exclusive...

            1. Anonymous Coward
              Anonymous Coward


              "'How do you know he's a fanboy?'

              'He might just be thick.'

              They aren't usually mutually exclusive..."

              In fact they show a correlation constant that quickly approaches 1.

      2. Gav

        @Neil Milner-Harris

        Selective indeed. If you read what it says, the whole point of the experiment was to see what the difference a "bumper" made. Which they did not test with a real thumb or real hand or real person.

        The test you are referring to was when the phone was held to demonstrated that it "reduced sensitivity" of the antenna. Which is not news to anyone, and wasn't the point of the experiment.

  9. Aramando

    You'd think I would notice...

    ... if my iPhone 4 was 100 times less sensitive to GSM/3G/WiFi signals when I held it!

    But I haven't. It's not even slightly less usable.


    1. Paul Crawford Silver badge

      @I would notice

      "if my iPhone 4 was 100 times less sensitive"

      You forget that 100 times is 20dB, a big but not catastrophic difference to something like a mobile phone.

      True that in free space it would represent a 10 time difference in distance, but in most mobile situations (e.g. in a city) you are pretty close to the base station and the phone can adjust its power to compensate, probably by over 20dB, so you see little effect on operation just a shorter battery life.

      So you tend to get dropped calls when the network is busy and/or where you are further from the base station (but still in the nominal coverage zone).

    2. Anonymous Coward
      Anonymous Coward

      Not odd at all.

      One of the chacteristics of 3G/GSM phones is that they (and the base station) adjust the power required to the minimum necessary, to limit interference and save battery life. Faced with a poor antenna, the phone will just blast out more signal. It would only be in situations where the signal is already poor that you'd actually see problems, dropped calls, etc.

    3. Anonymous Coward

      Not at all odd

      Apple design products for their known fanbase. Accommodating people with an opposable thumb is therefore not required.

    4. Terry Barnes


      Go look up on wikipedia about decibels and then come back.

      No reduction in signal will make it any less usable until it stops working. The point is that the amount of degradation and the method in which it is introduced means that point will be reached sooner than with other phones.

  10. tedl

    Yes we knew this

    I think the conclusion was that even with the antenna detuning the iPhone 4 had better reception than the iPhone 3.

    And if a bumper does not help then why not expose the antenna rather than sticking it just inside the plastic case like most smartphone do? Then iPhone 4 with a bumper is exactly like the iPhone 1-3 antenna placement wise.

    My own experience with the iPhone 2 and iPhone 4 is that I get a little better reception with the iPhone 4. I use a bumper for glass protection but will probably remove it after a year or so when the phone isn't so shiny.

  11. Lewis Mettler

    no real surprise

    No real surprise, really.

    Anyone who has messed around with radio antennas knows that you can receive some rather strange results. Even today's digital TV signals present some very interesting situations. Such as the orientation of a LCD monitor some feet away from either the TV or the antenna. It changes the reflected signal. And at marginal receptive times, the effectiveness of the antenna can be observed. Some have even claimed that getting up to take a break affects the signal. No doubt it can happen.

    Touching the antenna does detune it. And being nearby can do so as well.

    Surely this can affect any handheld device. You have a big bag of mostly water so near the antenna. And that can affect the signal.

    Only an idiot would design an antenna that in normal use is being touched by the user. Holding it just so probably helps. But, it is a bad design decision. Would you buy a car that heads into the ditch if you do not hold the steering wheel just right?

    1. Ian 25


      @Lewis Mettler: all cars are *designed* to head into the ditch if you do not hold the steering wheel just right (take your hands off the wheel and feel the drift)'s better to head ditchwards than oncoming trafficwards

      1. Andrew Norton

        cars head ditchwards?

        er no, cars go straight ahead if you take your hands off the wheel (assuming the wheel was straight to begin with)

        If your car is heading ditchwards, I'd take it to a garage ASAP and get it's alignment done quick-smart, because you're wearing your tyres unevenly, and could have them fail on you.

        If your front-end alignment is ok, then it might be that you're experiencing the 'crown of the road'. Put simply, roads are not 'flat' but curved slightly, with the center slightly higher than the outside edges, so that water goes to the side, for drainage, reducing ponding.

      2. Jedit Silver badge

        Er, no

        Cars aren't designed to drift into the outside. Roads are designed to drift all uncontrolled objcts to the outside. Look up "camber" and you'll understand.

        The better analogy is not buying a car that drifts to the outside of the road if the wheel isn't properly held, it's buying a car that drifts out because the wheel CANNOT be properly held.

  12. JaitcH

    They knew this 68 years ago in the desert

    Way back when Montgomery was chasing Rommel around the deserts of North Africa, the tanks had No. 19 sets which had an HF (High Frequency) main transmitter/receiver and a UHF transmitter/receiver compromising, I think, only one or two valves (tubes in North America) - the oscillator was also the 'power' amplifier, the other tube being the FM modulator. (See: < >. The UHF unit is next to the power supply connector).

    Apart from the tanks in the desert disrupting UHF transmissions in the UK (really), these UHF units could also be detuned off the operating frequency by grabbing the short antenna.

    But I guess the Apple antenna specialists are more interested in re-inventing the wheel. Even square ones.

    1. The First Dave


      Grabbing the antenna of a high-powered field radio can often impair the performance of the soldier quite drasticly, and is not to be recommended.

      1. M Gale

        Oh hell yes.

        "Just hold this a minute", he said. I tell you, a 100w rig being keyed up is as effective as a cattleprod for various assorted bastardry.

        1. Terry Barnes


          ...and the never-healing RF burn will serve as a constant reminder of your 100w japes.

      2. Tempest

        If I recall from my days in the Royal Signals ...

        these UHF sets were just for squadron inter-tank chat and had a power level of under one-quarter watt.

        I never heard of anyone dying, or even getting burned, by grabbing a quarter-wave dipole.

        The desert UHF sets jamming the assembly areas for D Day in the UK were due purely to 'skip'. These days 'skip' signals can't be heard because of the traffic carried on UHF.

  13. Bruce Hoult

    No problem in practice

    The funny thing is, when I was camping in some remote spots this (southern) summer, very often the people with iPhone 4's were happily using SMS or on the internet while other types of smartphones had nothing at all.

    When you're not bridging it, the external antenna works brilliantly.

  14. 88mm a.k.a. Minister for Misbehaviour
    Paris Hilton

    Gadaffi has WMD... but they still have to be mixed* - I think he forgot to pay someone!

    How is it when you touch an old fashioned VHF antenna the signal improves but this effect is reversed on a phone? In fact everyone knows by now that remote car unlockwidgets have a longer range when held to the head. And in another story... my old Audi manual stated not to use a mobile phone inside the car without an external antenna as the signal was increased to dangerous levels within the car.

    Paris, because I've seen her MIMO

    *Some people don't get innuendo, so... Claiming WMD is just a convenience to excuse military action and excuse not getting involved in countries without oil.

    1. Vladimir Plouzhnikov


      I think you will find that in the US any grenade or dynamite stick is now classed as WMD as the recent arrest of a Texan wannabe-terrorist shows. I'm sure it is just a matter of time for this to cross the Atlantic and we will soon see yoof found in possession of fireworks charged as if they were planning to set off a nukular explosion.

    2. Alister

      VHF is different

      VHF radio uses radio frequencies which are much much longer wavelength than those used by mobile phones - and therefore behave differently when a big bag of water gets in the way.

      However, you can still upset the antenna matching even at VHF wavelengths if you grab it in the wrong place.

      The other thing to bear in mind is that a radio receiver is not as sensitive to a miss-matched antenna as a radio transmitter is, a receiver will continue to function quite well or even improve slightly, whereas a transmitter will lose lots of effective power - or in extreme cases fry itself - when attached to a badly miss-matched antenna.

      As a mobile phone needs both a transmitter and receiver to function, it is the transmitter bit that suffers.

  15. Anonymous Coward

    Raising the dead....

    So the "Antennagate" episode still has not been laid to rest!

    I need to ask who who paid for this research? I do understand Universities are meant to research issues, but does the iPhone need or deserve this type of attention?

    No wonder the government of the day are reducing funding and increasing tuition fees, universtities are squandering time and money flogging dead horses and/or researching the obvious

    Now Mr. Uni Boffin, go research something meaningful like the fact that Global Warming is a natural process and not a man made issue. Hopefully the new government will read your useful research and not impose any more "green taxes" on us

    1. Anonymous Coward
      Anonymous Coward

      Wrong place

      I think you'll find the Daily Telegraph's comment boards are the next one over.

  16. Getter lvl70 Druid
    Paris Hilton


    Remember the stories of vibrating cellphones placed in odd areas of the body? By accident of course but what_kind_of_antennae_did_they_use? Enclosed by a body, yet still able to receive calls for that vibrating effect?

    Yeah, conduct THAT test! (I pick Chris 19 - since he didn't submit the proper paperwork for the research grant to get paid for his typing and subsequently gave his work away)

    AC@12:19 - depends. FM you become part of the circuit, AM you're a big resistor. Wavelengths and stuff I don't want to look up right now - it's complicated lol

    Paris, cuz she knows where to hide stuff.

  17. Vladimir Plouzhnikov

    A solution

    Add a large crank on the side and a purple lamp glowing brighter the better your antenna is tuned - it worked in Soviet tank radios since the 60's, so why not on the Jobsphone?

    Yes, it is that wheel in the middle with a chrome-plated folding crank and the bright red nut on it and the light above....

  18. Matt Bradley


    So the conclusion of this research seems to be that all smartphones suffer from signal loss problems when held in the wrong way.

    I seem to remember Apple posting this exact same conclusion last year, with demonstrations on a number of phones...

    Not sure how you've managed to spin this story into a criticism of Apple antenna design, given that it reaches exactly the same conclusion that they did.

    1. Anonymous Coward
      Anonymous Coward

      Spot the Dog

      "So the conclusion of this research seems to be that all smartphones suffer from signal loss problems when held in the wrong way."

      That's not the conclusion of this research. You are either a bit dim or doing some spinning of your own.

      Just in case it is because you are dim here is the real conclusion again:

      "iPhone 'Death Grip' effect is real, plastic cases don't help"

  19. D. M

    RE: Car

    I won't buy a car that won't work as a car, but many people will. You can however argue that not holding steering wheel correctly, can cause problem on rough road. A better expression would be: Apple sells new iCar, you have to dress in certain way, or else the car will not start/ will likely to crash. Drive in your shorts and T, you are dressing wrong.

    However, fanboy/girl lives in Jobs' fantasy walled garden, not real world. They will buy any crap Apple sells at any asked price.

  20. frood


    Am I missing something or don't mobile phones already automatically adjust tuning because of this effect?

    1. Terry Barnes


      It's possible to compensate and get the VSWR down to an acceptable level, but you can't magically replace the gain lost by attaching a conductive bag of water to your UHF antenna.

  21. Pavlov's obedient mutt

    is this give an old story a home day?

    I held out on an iPhone 4 because of the original version of this story - but then I got an AR Drone for christmas and my ancient 3G just couldn't hack it

    and you know what, I just don't get signal degradation *that-I-notice*

    perhaps its coz here in the Netherlands we have good signal coverage? I have no idea. Perhaps it's coz the actual effect in real life is nominal?

  22. Is it me?

    The answer is iPhone 5

    or at least a different set of problems, maybe, or it could be perfect, does that cover all bases?

  23. Tatsky

    Swings and Roundabouts

    It seems like anyone can take the facts and spin them however they want to support or criticise the iPhone. but at the end of the day the facts (in my humble opinion are):

    Put a human water bag next to an antenna and you get detuning (This is not a smartphone phenomenon)

    Make a human water bag touch the antenna, and the detuning is worse.

    Bridge the void between 2 separate antennas and you get further detuning

    This detuning in itself is not enough to cause serious signal loss. However, couple that signal loss with an already low signal and you get sufficient signal loss to cause problems.

    So all smart phones have this issue with detuning. Apple said this. It just so happens that Apple put their antenna(s) on the outside.

    So in the situation where you have:

    Human meat sack + bridged antenna + low signal area = Dropped calls

    However, from what I have heard (as I do not have an iPhone 4) the iPhone 4 for the most part has far superior reception in most cases, death grip or not. Combine that however with bridging, and low signal, and maybe a fair distance from the cell tower and you get dropped calls.

    So my summary of all this is iPhone 4 has a nice design and the antenna on the outside in the most part produces good results. However, throw a low signal in there along with the detuning and you have dropped signal.

    At the end of the day I have a Dell Steak, so I better move on now and charge it for the second time today.

    By the way, I cannot use my smartphone in my living room. The kitchen is fine, but the living room is a no. It doesn't matter how I hold it, or which chair I stand on, or whether I am swinging from the lamp shade or not, it won't get a signal. What's that about?

  24. Andy 97

    As any fule no...

    Changing the efficiency of an antenna can be affected by altering its standing wave ratio.

    Thank goodness we live in a world where designers can factor in the irregular way humans use hardware... oh!

    1. OrsonX

      no fuel?




      1. Cpt Blue Bear

        As any fule no... a literary reference. It's not an uncommon one on El Reg. I'll not insult your intelligence by explaining it, merely suggest that Google might be your friend. I think the OP deserves an apology for calling him a moron, don't you?

        1. OrsonX

          well I goolgled it...

          "fool knows"

          "fuel nows"

          "fool no"

          But to no avail... please enlighten me!

          1. Anonymous Coward
            Anonymous Coward

            Re: well I goolgled it...

            Calling someone a moron is very rude. Calling someone a moron because you didn't understand the reference makes you look very rude and silly.



            1. OrsonX


              OK, I stand corrected!

  25. TheOtherHobbbes
    Paris Hilton

    Dropped signal on my 4

    Completely reliable and reproducible. If I hold the phone in the usual non-Jobsian way, the bars drop and the call dies.

    If I delicately grasp it by the top edges only - as if it were a thing of almost infinite value, trembling poetically with lambent aesthetic wonder - I can make calls that last a few minutes. Until I forget what I'm doing in the heat of the convo and accidentally touch its forbidden areas again.

    Pile of pants if you ask me.

  26. Potts
    Thumb Up

    The iPhone 4 bumper works

    Simple as.

    The signal loss sans bumper was very annoying - maybe my big sweaty palms... Now with bumper, no noticeable signal loss. Simple, empirical evidence.


  27. Anonymous Coward

    "plastic insulation between hand and metal has no useful effect"

    So what do they suggest we use, then?

    Correct me if I'm wrong but don't pretty much all wireless consumer electronics employ plastic insulation between the user and the antenna?

    So from this can we conclude that wireless devices historically have always worked in a much-degraded capacity, and if we solve this problem then they will perform much better?

  28. ratfox
    Thumb Up

    And I thought the case was required for my iPhone to work

    I guess it is working pretty well, with or without case, then.

  29. rcdicky

    iPhone Bumper

    Am I reading this right?

    From what I gather they're saying most cases don't help the situation but that the iPhone 4 has a problem that "hasn't been investigated before" - this suggests they realised they needed to do further tests with the iPhone but didn't?

    Add me to the list of people who will have tested this then. Successfully death-gripped with no bumper - no change in signal with the bumper on

    (oh, and fwiw I can only recreate the signal dropping when intentionally wrapping my hand around the phone. Using it normally in my left hand does nothing)

  30. Doug Glass

    Capacitive Coupling ...

    ... is a beautiful thing to behold except when the beholding is your hand on the iFoney.

  31. Anonymous Coward
    Anonymous Coward

    No surprises here

    There is no great surprise here. People effect aerials, every antenna designer knows this and so does joe public; if he thinks about it. It's generally understood that you do not stand next to portable tv aerials.

    Apple have tried to do the right thing, maximize the volume of your antenna to maximize it's efficiency. The difficulty they have come against is that also makes them easier to detune. If you were going to be clever you would measure reflected power and have electronic tuning, but that is added cost and space.

    Also this has nothing to do with MIMO, that's a whole different field, if you pardon the pun.

  32. Alan Brown Silver badge

    detuning or not?

    If the antenna detunes due to extra capacitance when it's held in the hand, it's simple enough to tune it the other way to start with.

    I learned this a long time ago making helical 2GHz antennas - when we slipped a plastic shroud over them the resonant frequency changed. The solution was simply to set the free-air resonance a little higher.

    Similar tweaks were done with pagers many years ago. They _required_ being held or worn in order to achieve maximum sensitivity.

    On the other hand: Bridging the gap in a skeleton slot antenna will lead to all sorts of wierd effects and a guaranteed loss of sensitivity.

    Mine's the one with a Smith chart in it.

  33. Jonnyp

    thats all lovely scienceness BUT

    my iphone is unusable without a bumper and works OK with one.

    So there.

    Maybe these scientists should go do something useful, like make me a lightsabre or a hoverboard.

  34. maclovinz

    Engineer: I TOLD YOU SO!!!!

    Where is the engineer(s) screaming "I TOLD YOU SO!!!!!" right now?

    Just wondering.

    1. Vladimir Plouzhnikov

      Engineer is solving problems

      Need a dispenser here! Need a dispenser here!

  35. Anonymous Coward
    Anonymous Coward

    On a CDMA iPhone 4 equipped with an Apple "bumper"

    .... after strenuous, two-handed, multi-fingered efforts, I'm unable to budge the signal strength indictor off 3 bars as I sit here. Perhaps the GSM unit is different: the antennas have been redesigned for CDMA. Scant comfort for UK/Euro iPhonebois, if true.

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