My (brief) experience with the iPhone 4 [Updated x2]

Discussion in 'iPhone' started by Rend It, Jul 7, 2010.

  1. Rend It macrumors 6502

    Oct 27, 2003
    United States
    [Update: See post #29]
    [Update #2: See links to videos in post #35]


    I am returning my iPhone 4 tomorrow, and thought I'd share my experience with those who are interested.

    First some disclaimers/background.
    1) Please don't expect a bunch of pictures/videos of what I'm describing. I didn't have the time or patience. Those of you who have experienced similar issues will know exactly what I'm referring to.
    2) I am not an antenna or wireless systems engineer. However, I was once a EE with experience in wireless communications (2-way radios, cell phones). So, I have a modest understanding of the issues I discuss below.
    3) I have been an Apple customer for the last seven years, and have only purchased computers from Apple. I say this to dispel any notions that I'm trying to drum up various negative emotions about Apple.

    With that out of the way, here's what happened....

    • I bought my (refurbished) iPhone 3G January 2009. Despite its slowness lately, it makes for a pretty reliable phone. It is my only phone (no landline), so the phone function of the device is very imporant to me.
    • My house has plaster walls with a metal mesh backing. In other words, it's sort of like living in a Faraday cage. My wife's T-Mobile phone cannot make calls from inside. My 3G had no problem in this regard, and could even initiate and maintain calls from down in the basement! (Important since our office is down there). This was true before, but especially so after AT&T switched to 850 MHz in CO. This was one of my favorite aspects of my 3G. Believe what you may about cell phone "bars", but more often than not, I would get 5 bars in the basement, whether I was on iOS3 or iOS4.
    • Ordered iPhone 4 online and received it last week.
    • The iP4 never showed more than 4 bars in the house on the main level. In the basement, it struggled to get 2 bars. More importantly, I could not initiate calls. I could receive calls, but they would quickly drop after I picked up. This was true no matter how gingerly I held the phone. I then fitted my iSkin case from the 3G on the iP4, but the problem did not go away. In fact, even with the case on I could still kill the bars and stop data transmission with the usual "death grip".

    This led me to do a few crude tests. Before doing this, I followed AnandTech's trick of carrying over the field test mode from my 3G. This allowed me to know the signal level in dBm (decibels referred to 1 mW). Note that any given reading seemed to fluctuate by +/- 2 dBm; in rare cases the signal fluctuates as much +/- 4 dBm. Regardless, a change greater than or equal to 10 dBm is significant. Each 3 dBm change represents a signal power change by a factor of two, while a 10 dBm change represents a change by an order of magnitude. Without holding the iP4 the signal level in my house was typically -91 dBm, and max 3G data rates are around 1.5 Mbps down and 60 kbps up (uplink sucks out here).

    At Home. First, with no case I was able to repeat and confirm the usual death grip effect on the phone by palming it, as well as simply bridging a single finger across the gap on the bottom left. The signal went from -91 dBm to -113 dBm, a change greater than 20 dB, indicating signal loss by two orders of magnitude. The same effect can be had by placing the phone on it's right edge (looking from front) and placing a piece of metal over the gap (in my case, a wedding ring). This has been shown elsewhere with a key.

    Next I tried various holding arrangements to see if I could hold the phone in a way that did not lead to a reduction in signal. The only way was to NOT hold any part of the metal band, e.g., by squeezing the front and back glass with two fingers. Not exactly a comfortable position. You see, I could not avoid a significant signal loss in ANY of my normal, non-death-grip, hand positions. Of course the loss depended on where I touched the band, but even the smallest loss was more than 8 dB. I also tested data rates via the FCC app and time for loading Data rates did not seem to correlate strongly with signal level when I did not hold the phone. However, any holding position affected these rates, regardless of the starting signal level. These effects are summarized as follows:

    • Death Grip and Bridging Gap with Finger: True 0/0 kbps DL/UL on the FCC app and page loading ground to a halt. Signal level = -113 dBm to -109 dBm.
    • Normal Hold Bridging Left and Right Edges with Hand (away from gap): Signal varied between -107 dBm and -99 dBm. DL data rates varied between 100 kbps to 700 kbps.
    • Bag of Water: I filled a ziploc bag with tap water and (carefully!) laid it near the left edge of the phone. The bag's exterior was completely dry. Signal and data rates were similar to death grip. Placing bag anywhere else around the cell antenna did not have such a dramatic effect.
    • Death Grip with iSkin Case: Signal reduced to -113 dBm. Zero data rate outcomes seemed to occur as often as those with DL rates around 200 kbps.

    The last two tests indicate that the issue is not a matter of DC conduction between the cellular and WiFi antennas. A plausible explanation is capacitive coupling, which then results in a significant detuning of the cell antenna. Imagine a small capacitance between each antenna and the water or your hand. This also agrees with the recent discovery that electrical tape over the gap does not prevent the death grip effect.

    Around Town. I also spent some time testing the phone in various places around the Denver area. Signals ranged from -51 dBm (though I could not see any towers) and -107 dBm in a parking garage, all without holding the phone. Interestingly, when the signal was greater than -87 dBm, I could not get the signal to drop appreciably no matter how I held it! Granted, I did not test this aspect exhaustively, but this may be the most surprising outcome of all. It would also explain, in addition to Apple's weird bar-to-signal mapping, why some people never observe a reception issue. The detuning/attenuation only becomes a problem for signal levels lower than about -87 dBm.

    In the end, the inability to use the phone reliably in my house is why I'm returning it. A case does not help. I also went to AT&T and got a new SIM card, but that failed to help either. Maybe I got an awesome 3G. Perhaps there is a manufacturing defect in my iP4. Or perhaps more plausibly, this guy hit the nail on the head. Regardless, I'm returning to my trusty 3G until the smoke clears, and it seems like the iP4 (or iP5) is actually a good phone, in addition to being an awesome "everything else". I don't think Apple will drastically change the hardware in response to this, but I do believe that they will try to make minor software (as well as hardware!) mods to help mitigate the worst scenarios. It may mean a slight PCB redesign or adding some small mods to the antennas (on the inside of course :D). Regardless, I'm a wait this one out.

    Besides, there are simply no nice cases for the iP4 yet! :p
  2. Alphaspida macrumors member

    Jun 14, 2009
  3. Russiaone macrumors 6502

    Jun 7, 2010
    tl;dr wall 'o text

    warning, whiner in this topic
  4. falconeight Guest


    Apr 6, 2010
    Man I got a 1/4 through the story, but it was brining me down. You should of just returned the phone flipped the sales person the bird and called it a day. No need for all the dramatics.
  5. Fernandez21 macrumors 601


    Jun 16, 2010
    He just said he would.

    Op, I appreciate your findings, hopefully apple will fix this somehow, either through software hardware. You should also forward your expierences to apple when you return the phone, hopefully with enough feedback they will get to the bottom of this issue.
  6. falconeight Guest


    Apr 6, 2010
    Its been on every major news source. I think apple understands the problems.
  7. Rend It thread starter macrumors 6502

    Oct 27, 2003
    United States
    Yes, it is a lot of info, but I thought the details would be useful to those experiencing similar problems. If you're not experiencing problems, then this thread is not for you.

    Oh, and I did try to return the phone today, but you can't return iPhones bought at the online Apple Store to a retail location. I'm shipping it back to Apple this week.
  8. Loiterer macrumors member

    Jun 23, 2010
    Wow, someone actually tries some kind of useful systematic testing and even follows the time-honored Apple fanboy wrath-dodging technique of prefacing the post with how many Apple products he's bought and people still flame him? Sorry guys. Back to your scheduled "MY ONE SINGLE PHONE WORKS FINE SO YOU ALL MUST BE TROLLS MAKING UP LIES WHO HOLDS A PHONE IN THEIR PALM ANYWAY LOL"
  9. Soulcrux macrumors 6502


    Nov 8, 2008
  10. Rend It thread starter macrumors 6502

    Oct 27, 2003
    United States

    While I don't think my experiences are particularly new or uber-useful to Apple, I disagree that Apple understands the problem. I think they are aware that there's a problem, but I doubt that they fully understand (at least for now) what's causing these problems. I think it's truly a complicated issue. See the link at the end of my original post. He's a lot smarter about these things than I am.

    The point of my post was to describe some of the nerdier, more obscure aspects of the reception problem, since Apple will never ever offer a full explanation.
  11. KameronBriggs macrumors 6502


    Feb 8, 2010
    Somewhere Sunny, California
    There are some jerks on here, man.
    Thanks for your post, it's convincing me to keep my trusty 3GS longer. :cool:
  12. DoNoHarm macrumors 65816


    Oct 8, 2008
    OP, Thank you so much for this incredible post! It's backed by data instead of these stupid emotional one liners that others constantly spew out on these boards. Your experiences have helped others and I'm glad you've shared them on this board.
  13. ARSC macrumors 6502

    Jun 27, 2010
    Good op buddy. Leave the person alone its his wish what to do.
  14. br0adband macrumors 6502a


    Aug 29, 2006
    To the OP:

    Ignore the boneheads, idiots, and trolls that will attempt to dissuade you from sharing the info based on your firsthand experience. This is a discussion forum primarily focused on Apple products and services hence people are free to post positive things as well as negatives, especially when they can back either one up with actual experience.

    The only website on the Internet that should be nothing but Apple preaching and good stuff is itself... everywhere else, they're fair game when they deserve it, which means right about now.

    Sorry your iPhone 4 experience wasn't a positive one but perhaps things will get worked out over time. It's going to take a lot more than some software update "fix," however.

    Nice to see the AntennaSys coming around to what I and many others have said since day 1:

    "It's the antenna, stupid..."
  15. Rend It thread starter macrumors 6502

    Oct 27, 2003
    United States
    You are very welcome!

    Colbert Report is on next, so good night for now guys and gals. :)
  16. QuarterSwede macrumors G3


    Oct 1, 2005
    Colorado Springs, CO
    OP great post and you're exactly right, it's not DC coupling bit it has everything to do with how close your hand is to the antenna in that particular location. I've been listening to a few RF/cell engineers on TWiT that have confirmed this as the most likely situation.
  17. Compile 'em all macrumors 601

    Compile 'em all

    Apr 6, 2005
    That was an interesting read. Thanks for posting!
  18. Dallious macrumors member

    Jun 28, 2010
    Your post is for sure one that sums it up pretty good, thanks
  19. 2000m macrumors member


    Jul 17, 2008
    Great post, after reading this i am convinced to hold on to my 3gs a little longer
    thanks again
  20. vijayvasa macrumors member

    May 28, 2010
    Excellent post , and this post prooves that you are knowledgable with the issues and able to say them. Ignore the idiots and one liners who knows only to type few sentences and words.
  21. Leftyum macrumors newbie

    Jul 2, 2010
    Nice write up OP. Don't worry about the Apple fanatics who click on the thread only to make idiotic statements. They're just mad that apple ****ed up, big time.
  22. VladM macrumors regular

    Oct 23, 2008
  23. WeegieMac Guest


    Jan 29, 2008
    Glasgow, UK
    One of the better constructed posts.

    The only thing that jumped out at me was that you said you got your refurb iPhone 3G in January 2008.

    I take it you meant 2009?

    Also, you confirmed my own experience, in that when I'm in a strong area of reception and receiving five bars on 3G, I cannot make a single bar drop.

    At home, where our O2 signal is a poor GPRS at best, I can cause the "antenna issue" no problem.
  24. WeegieMac Guest


    Jan 29, 2008
    Glasgow, UK
    Yeah, God forbid that Apple fans come on an Apple forum to defend an Apple product.

    Honestly, your own logic is as twisted as those you "speak out" against.

    Why sign up to an Apple news forum then moan when Apple fans defend Apple?

    It's like me, being a Rangers supporter, signing up to a Celtic forum and bitching about why everyone is pro-Celtic. It's pointless and borderline stupid.
  25. Amnesia87 macrumors 6502

    Jun 19, 2010
    So basically you wrote that giant wall of text to say that you are returning your phone because it's doing exactly what the tests at Anandtech showed it would do?

    Can I please have the minute of my life I spent reading this post back. I've already heard this story, and I fail to see what the point in posting it was other than to be obnoxious.

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