interesting death grip bars dropping case

Discussion in 'iPhone' started by mrFinder, Jul 5, 2010.

  1. mrFinder macrumors member

    Joined:
    Jun 25, 2010
    #1
    in my house, i get around 4-5 bars of 3G. referring to anandtech's study, that means that i am on the lower boundary of the 5th bar/upper boundary of the 4th bar, putting me approximately in the -94dB to -85dB. now, when i "death grip" the phone, the bars DO drop all the way down to 1 bar, as expected, but interestingly, they go all the way back up as well. i understand completely why the bars drop when "death gripping" (the signal gets attenuated by a max of -24dB), but what I don't understand is why the bars go back up. i am not changing the grip of the phone at all. if i hold the phone for about 15 seconds, it'll take about 5-7 seconds to drop the bars and then another 5-7 seconds to raise them back up. and once they are back up, they don't drop anymore when "death gripping" unless i restart the phone or reset network settings. so i just wanted to know what the reason is for this. i haven't really been getting dropped calls, so it's not really an issue, but i'm just curious as to the theory behind this.
     
  2. rotobadger macrumors 65816

    rotobadger

    Joined:
    Sep 18, 2007
  3. mrFinder thread starter macrumors member

    Joined:
    Jun 25, 2010
    #3
    hmmm, could be. i'm not too familiar with how the tower switching works. so when the bars dropped down to 1 bar, the phone searches for a new tower? if so, why didn't the phone just pick that tower in the first place, if in fact it does give better signal. i thought there was some improved algorithm that the iPhone 4 uses that allows it to automatically connect to towers that provide the best signal.
     
  4. Julien macrumors G3

    Julien

    Joined:
    Jun 30, 2007
    Location:
    Atlanta
    #4
    Tower switching is 100% invisible to the consumer. Also bars are not meaningful at all and are just a hold over from when cell service was analog (when they were meaningful). Forget the bars, as long as you have a connection you are fine.
     
  5. Eso macrumors 68000

    Eso

    Joined:
    Aug 14, 2008
    #5
    It's because you just dropped to EDGE.

    You can't get back to a 3G connection without resetting the network settings...

    ...and you are saying this isn't an issue?
     
  6. mrFinder thread starter macrumors member

    Joined:
    Jun 25, 2010
    #6
    uhh actually i didn't drop to EDGE. the bars dropped from 4-5 down to 1 bar (still 3G) and then right away they went all the way back up to 4-5, where they started, and would not drop again until i restart the phone or reset network settings. in all of this, i can hold on to a phone call just fine, making this a non-issue, like i stated in my original post. i am just curious as to why the bars go back up. most people who were reporting this problem were able to get the bars to drop down to 1 and even got it to say "searching," and it would stay in that state until they let go of the phone. in my case i am holding the phone the entire time and the bars drop and then they go right back up, even if i don't let go. make sense? so my question once again is why does this happen?
     
  7. jonstatt macrumors member

    Joined:
    Jun 28, 2010
    #7
    While the signal is digital you could argue all you need is "yes there is a signal, or no there isn't".

    But I disagree the bars are a hangover from analog. They provide a useful understanding of how close you are to being at risk of losing signal. If you see only 1 bar, the chances are as soon as you put it in your pocket you will have nothing...so this tells you to keep your phone out if possible.

    I think we are going to see 1000s of posts saying its a hangover from analog because of a certain podcast. But while the sentiment is valid for digital signals, it is not a valid statement in practicality.

    Even in the digital world, aside from mobile phones, we measure signal strength and signal quality. For digital TV this tells us how well aligned we are so that the signal survives through bad weather.

    Also note that a clear signal is not the same as a strong one. Signal quality is related to signal-to-noise ratio and refers to the amount of errors it is correcting. Signal strength, is as its name suggests, indicating how strongly in dBm the signal is. You can have a strong signal but with loads of interference so it is NOT a a clear one..and has many errors. You can have a weak signal with low interference and is a clear one.
     
  8. Eso macrumors 68000

    Eso

    Joined:
    Aug 14, 2008
    #8
    I already told you, you are dropping to EDGE (although you claim otherwise). Often times '3G' is displayed because the phone doesn't know any better until you try to use data - the circle spins while it starts loading, then the 3G icon is replaced by an E and the page loads.

    Make sure WiFi is off and you have restarted your phone, and then use the speedtest app to see for yourself.
     
  9. mrFinder thread starter macrumors member

    Joined:
    Jun 25, 2010
    #9
    but this still doesn't answer my original question. even IF it may be EDGE, why do the bars go back up right away, even if i don't let go of the phone.
     
  10. Eso macrumors 68000

    Eso

    Joined:
    Aug 14, 2008
    #10
    The EDGE signal is stronger than 3G at your home. It's the same case at my local Apple store where I observed the same behavior you are. It is located in a fairly new shopping area 5 miles south of town. Consequently, the 3G coverage is spotty, but the EDGE coverage is strong.

    I was comparing my 3GS to the iPhone 4 last week in the store. Both phones were showing 2-3 bars of 3G connection, but it was terribly slow. Detuning the iPhone 4 would drop it to EDGE and it would not pick up the 3G signal even after removing my finger. To be fair, the EDGE connection was just as fast as the 3G was at this location, but the signal was stronger so it was more reliable (half the time my 3GS on 3G would just spin and spin and never load a page).

    In my opinion based on my observations, the detuning affect is much less severe for frequencies used for an EDGE connection than those used for a 3G connection.
     
  11. Julien macrumors G3

    Julien

    Joined:
    Jun 30, 2007
    Location:
    Atlanta
    #11
    Not really, with the iphone you still have a very strong signal at 1 bar. With the current scale you would need about 10 more bars to be a good indicator. AT&T update the recommended algorithms for calculating the signal so that the bars are more realistic (though still unnecessary) but Apple didn't adopt this method. Now Apple's is changing to this method. However they still don't provide actual user info since cell tower switching and signal variations are always happening. Apple needs to put back the Field test since this is the only true way to determine signal.
     

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