Discussion in 'iPhone' started by andylee97, Jul 18, 2010.

  1. andylee97 macrumors newbie

    Feb 28, 2008
    So I was looking at my phone and I see three lines separating the antennas. so I was thinking why are the lines there in the first place. well there are there because each piece has a specific function and they put those black lines there so that the antennas wont touch and interrupt each function.

    so my theory is when you place your finger on the line you are somehow connecting the two pieces together with your finger as a conductor and that somehow interrupts the flow of something and it causes the signal to drop.

    I've done test where my finger almost touching the line and I dont have a signal issue only when I actually place my finger and connect the to metal pieces together then I have an issue.
  2. appleguy123 macrumors 604


    Apr 1, 2009
    15 minutes in the future
  3. andylee97 thread starter macrumors newbie

    Feb 28, 2008
    I saw the conference and it only mention that if you touch that spot you will lose signal. But it didnt explain why. I think that somehow the bottom piece of the phone shouldn't touch the antenna piece and they place the line to prevent it from touching but when you place your finger there you are connecting your fingers energy or something and that is messing up the signal.
  4. Broph macrumors 6502


    Jun 23, 2010
    New Zealand
  5. murdercitydevil macrumors 68000


    Feb 23, 2010
    I have a theory - you didn't read a single word about the antenna issue before posting this.
  6. M-5 macrumors 65816


    Jan 4, 2008
    This is pretty much common knowledge that everyone just assumes everyone knows. It's not some strange new complex theory.
  7. Block macrumors 6502a


    Jun 28, 2007
    Don't be so harsh on the OP, everyone has to learn about it sometime. At least he figured it out. :p
  8. moka macrumors 6502a

    Aug 11, 2008

    not necessarily, It all depends. If you are in a good coverage area you will not experience any bars dropping if you hold or put your finger between the two antennas, i tried it with a Displayed iPhone in an apple store at the irvine spectrum center, CA and the phone started loosing bars, when i tried it with a fiends phone that lives in Ladera Ranch CA, the phone held its 5 bars, so i would not say its shorting the connection because it would still be loosing signal.
  9. JulianL macrumors 65816

    Feb 2, 2010
    London, UK
    Actually, in a way I think he's got a clearer idea than some of the comments elsewhere that are fixating on attenuation by obstruction of signal. I suspect that all this talk of hands and other body parts blocking the signal is the most minor and least interesting part of this. The bigger issue that is unique to the iPhone is the bridging of that gap.

    Where the OP is wrong (I think) is that it's not that it "interrupts the flow of something", it's more that it allows a flow between the two antennae that bridges them to some extent, changes the resonant frequency of the main cell antenna, and detunes the antenna sufficiently to degrade the signal reception. If you think about it then a mm or so of plastic between a hand and the antenna isn't going to do anything to remove that hand from the path of the signal between the cell mast and the phone but it does stop the finger from touching that gap (there might still be some bridging though because there could still be some capacitive effect with the bumper acting as the dialectric).

    It will be interesting to see what Apple do in the next hardware revision (in my opinion probably at the next generation at WWDC 2011) to reduce the effect. Coating the area is probably the least good solution because I think there would still be a strong capacative coupling with anything less than a bumper-like covering so short of moving the antennae inside again (and I hope they can avoid that because I love the new form factor) they're left with trying to move the join to a less exposed place or finding some way to dynamically retune the antenna when the gap is bridged.

    I think that a lot of people missed the hidden message when Apple showed off their $100m test facilities and I've seen a lot of stupid comments on this forum to the effect that it's no good having expensive test facilities if you don't use them properly; presumeably such posters know more about antenna design and testing than a bunch of Apple engineers who probably have many hundreds of years of cumulative experience in antenna design and testing. The mostly unstated message from Apple showing off that facility (although they did mention PhD count) was "Do you really think that we'd spend $100m on a test facility and then not staff it with some of the best antenna experts in the world?". I'd bet on the fact that Apple have some very smart engineers working for them and the next iPhone will show significant improvements in this area.

    As for how Apple got themselves in this situation in the first place, I'm not sure, but I think it crazy to believe that it was because their engineers didn't do something really basic like test it enough in the wild or fail to model, test and analyse the bridging effect. Maybe they genuinely did believe that the performance was close enough to their competitors so as to not cause this furore of press and consumer reaction.

    - Julian

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