06-10-10 01:05 PM
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  1. Radius's Avatar
    I just lifted this from CNN:

    The iPhone 4 is flat on the front and back, and a band of stainless steel goes around the edge as a trim. This isn't just a design feature, Jobs said. It's actually the antennae.
    How and why? This really doesn't fit, and would be a very bad antenna. Here's a bit of background for people wondering what I'm on about.

    The optimal antenna is 1/4 the length of the wavelength the phone is using. The formula is (frequency / speed of light)) / 4 = lenght and that gives you the optimum length of the antenna.

    So assuming this thing is running at 850Mhz or 900Mhz the bezel is still far too long to be an effective antenna. You can add circuits called antenna coupling circuits to modify this rule slightly but it still falls far outside the optimum length.

    So what's going on here? Did they sacrifice quality for aesthetics? Not to mention if the whole bezel is in fact one unbroken antenna then it may be considered an extremely directional loop antenna. So while you face right at a cell tower you would get unparalleled reception, turning away a few degrees would really cut down on quality.

    Or am I missing something here?
    06-08-10 05:25 PM
  2. andyahs's Avatar
    Is this not the General BlackBerry Discussion Forum.

    There is an iPhone forum.
    06-08-10 05:30 PM
  3. devGOD's Avatar
    I just lifted this from CNN:



    How and why? This really doesn't fit, and would be a very bad antenna. Here's a bit of background for people wondering what I'm on about.

    The optimal antenna is 1/4 the length of the wavelength the phone is using. The formula is (frequency / speed of light)) / 4 = lenght and that gives you the optimum length of the antenna.

    So assuming this thing is running at 850Mhz or 900Mhz the bezel is still far too long to be an effective antenna. You can add circuits called antenna coupling circuits to modify this rule slightly but it still falls far outside the optimum length.

    So what's going on here? Did they sacrifice quality for aesthetics? Not to mention if the whole bezel is in fact one unbroken antenna then it may be considered an extremely directional loop antenna. So while you face right at a cell tower you would get unparalleled reception, turning away a few degrees would really cut down on quality.

    Or am I missing something here?
    i'm pretty sure they tested it, especially with how anal Steve Jobs is about things. they wouldn't have done it if they thought it wouldn't be an effective antenna. I'm pretty sure your points are right but technology changes daily so what they're doing and using now for antenna could be something regular people don't know about yet.
    06-08-10 05:31 PM
  4. Radius's Avatar
    No idea, I just hit post. Isn't this place smart enough to know what I'm posting about?
    06-08-10 05:32 PM
  5. Radius's Avatar
    i'm pretty sure they tested it, especially with how anal Steve Jobs is about things. they wouldn't have done it if they thought it wouldn't be an effective antenna. I'm pretty sure your points are right but technology changes daily so what they're doing and using now for antenna could be something regular people don't know about yet.
    Yes technology changes, but the laws of physics have remained relatively constant.

    See what I just did there?
    06-08-10 05:33 PM
  6. andyahs's Avatar
    This whole page is full of iPhone 4 crap!!
    06-08-10 05:34 PM
  7. Radius's Avatar
    Actually it's more or less full of physics and RF theory so that's why you're confused.
    06-08-10 05:39 PM
  8. jay0heavenly's Avatar
    Since the phone isn't yet released this is just my very humble opinion. That being said, this phone will have much BETTER reception than previous models because I'm banking on the fact that the Physics people at Apple are a heck of a lot smarter than the OP.
    06-08-10 05:41 PM
  9. Radius's Avatar
    Since the phone isn't yet released this is just my very humble opinion. That being said, this phone will have much BETTER reception than previous models because I'm banking on the fact that the Physics people at Apple are a heck of a lot smarter than the OP.
    First of all I'm not bashing Apple, just very curious. Second, what Jobs said flies in the face of basic RF principles. If you like I can slide over to our RF engineer and get some real technical details from a trained and certified individual in the field.

    Anyhow, I am more curious than anything. To me it doesn't make sense to do it this way when one of these new fangled fractal antennas could possibly do the trick if that's even possible. I am no expert on that technology though but it's my understanding they act to enhance antennas themselves so maybe they've hidden a few under the hood somewhere.
    06-08-10 05:48 PM
  10. LazyStarGazer's Avatar
    The metal band is made of Quantum Recievers, which flash in and out of existence sequentially. Essentially, it's a material that thumbs it's nose at your RF laws. Much like giving the finger to a cop with a radar gun in his hand as you drive by.
    Last edited by LazyStarGazer; 06-08-10 at 06:19 PM.
    06-08-10 05:50 PM
  11. Radius's Avatar
    The metal band is made of Quantum Recievers, which flash in and out of existence sequentially. Essentially, it's a material that snub it's nose at your RF laws. Much like giving the finger to a cop with a radar gun in his hand as you drive by.
    I never did the cop thing but my buddy offered one a box of donuts he had when he got pulled over for speeding once.

    The cop was not amused to say the least but he got off with just a speeding ticket.
    06-08-10 05:52 PM
  12. edward47150's Avatar
    I don't know about the exact length, but not the whole thing is for the GSM. Ther are two breaks on each side. Part of it is for GSM and the other is for bluetooth and wifi.

    Posted from my CrackBerry at wapforums.crackberry.com
    06-08-10 05:58 PM
  13. scorpiodsu's Avatar
    The OP is really reaching to find something wrong. Everyone knows how anal Apple is about aestetics so they definitely wouldn't have done this if it wouldn't work. They remember the signal issues with the original iPhone and then all the crap AT&T gets for it's network. I'm sure they spent a lot of time to make this work. The OP seems to think he knows more about this stuff then the designers and executives at Apple.
    06-08-10 06:00 PM
  14. Radius's Avatar
    Ah, this is starting to make sense. I will have to measure one up and see what they have done. I suspect they made one side the perfect length for GSM and just approximated for bluetooth and Wi-Fi. The last two would use a much shorter antenna as they run at much higher frequencies than a regular GSM signal.

    Maybe the theory being if you are in range of bluetooth or Wi-Fi then you are very close so signal quality can be less and no one will notice.
    06-08-10 06:01 PM
  15. Radius's Avatar
    The OP is really reaching to find something wrong. Everyone knows how anal Apple is about aestetics so they definitely wouldn't have done this if it wouldn't work. They remember the signal issues with the original iPhone and then all the crap AT&T gets for it's network. I'm sure they spent a lot of time to make this work. The OP seems to think he knows more about this stuff then the designers and executives at Apple.
    I think you are reaching. This is all about my curiosity. I work with this stuff both directly and indirectly most days so when someone comes out with claims like this I get very interested.

    I'm not saying it's impossible, it's just very curious. There are ways they can partially compensate but what's really going on here? I want to go buy one now just so I can tear it apart and see, the unanswered questions are killing me.
    06-08-10 06:02 PM
  16. LazyStarGazer's Avatar
    Radius, Metal bands are for sale in China.

    When you get one, hold it up with one hand, waving it to and fro, while saying
    "Can you hear me now?"

    Metal bands can also be found in the 80's section at your local record store.

    BTW, for the record (ouch) I know you are truly just curious about this.
    06-08-10 06:26 PM
  17. LazyStarGazer's Avatar
    06-08-10 06:29 PM
  18. TheScionicMan's Avatar
    OMG, blasphemer... LOL
    06-08-10 06:48 PM
  19. iCandi's Avatar
    im pretty sure that steve jobs uses this damn thing and if it didnt get ungodly reception with the new design it wouldnt have it. just my 2cents.
    06-08-10 06:48 PM
  20. scorpiodsu's Avatar
    I think you are reaching. This is all about my curiosity. I work with this stuff both directly and indirectly most days so when someone comes out with claims like this I get very interested.

    I'm not saying it's impossible, it's just very curious. There are ways they can partially compensate but what's really going on here? I want to go buy one now just so I can tear it apart and see, the unanswered questions are killing me.
    Yeah whatever. You're reaching because you are a hater. Just like in the other thread you're talking about how multitasking will work without draining the battery. It already does it on jailbreak without any change in performance. But since you're a hater you're quick to raise questions about your skepticism. I get it.
    06-08-10 08:16 PM
  21. LazyStarGazer's Avatar
    im pretty sure that steve jobs uses this damn thing and if it didnt get ungodly reception with the new design it wouldnt have it. just my 2cents.
    Yes, just like it did during his keynote address.
    Wait...
    06-08-10 08:25 PM
  22. Branta's Avatar
    Leaving aside a few personal attacks by morons, this seems to be a valid question. Cut out the fighting and play nicely.

    There are a few potential misconceptions in some of the questions and responses.

    The optimal antenna is 1/4 the length of the wavelength the phone is using. The formula is (frequency / speed of light)) / 4 = lenght and that gives you the optimum length of the antenna.

    So assuming this thing is running at 850Mhz or 900Mhz the bezel is still far too long to be an effective antenna. You can add circuits called antenna coupling circuits to modify this rule slightly but it still falls far outside the optimum length.
    Considering dipole and 1/4 wave ground plane antennas this is the simple case. However any odd multiple of 1/4 wave should behave acceptably - certainly in the single digit multiples but it can get a bit squirrelly at higher numbers. UHF and SHF are strange and intolerant for the engineer, and as frequency increases the wavelength decreases making dimension tolerances tighter in inches (still the same if measured in wavelengths).

    With the right combination of inductance and capacitance it is possible to match almost any transmitter to any antenna without significant losses. Obviously it helps if it is somewhere close to tuned length and impedance, and some silly lengths will never tune in reality with a practically achievable matching network. I have seen the most unlikely combinations achieve an acceptable match, like a 2m wire on a 2MHz transmitter (the feed wire for a much longer antenna was broken).

    Antenna matching with an exposed antenna will be complicated by the different loading applied by different users, and even changing grip would alter the coupling to the user. At least in theory the user's entire body could become part of the antenna, depending how the phone is held.

    Not to mention if the whole bezel is in fact one unbroken antenna then it may be considered an extremely directional loop antenna. So while you face right at a cell tower you would get unparalleled reception, turning away a few degrees would really cut down on quality.
    That might be the case for a true loop antenna - a broken loop fed from each end (think like the Ohm symbol). Your description sounds more like a single continuous loop with single feed which would simply behave like a very fat, wide 1/4 wave antenna. Consider it as a flat plate connected at one point on the perifery, with a hole drilled through the middle of the plate. The hole doesn't change the behavior. Now expand the hole so the plate becomes a rectangular ring.

    Others have suggested the ring is actually split into several antennas. Maybe we need one to rip apart and examine. Any volunteers willing to donate a test piece?
    06-08-10 09:40 PM
  23. LazyStarGazer's Avatar
    *Nods sagely in agreement, pretending he understood what Branta just said.*
    06-08-10 10:16 PM
  24. yoyola's Avatar
    this iPhone 4 is very nice look,and style,
    06-08-10 10:23 PM
  25. edward47150's Avatar
    Again, I don't have all of the tech knowledge, but look at the keynote on apple.com from the announcement. Go to 33 Min 23 Seconds in and it is explained.
    06-09-10 12:53 AM
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