Test your iPhone’s antenna with iOS 4.1’s Field Test

InvisibleSHIELD.  Scratch Proof your iPhone 4!“Apple has re-introduced field test mode in iOS 4.1, which will allow you to quickly check the quality of your cellular signal by simply dialing: *3001#12345#* and pressing Call on your iPhone,” David W. Martin reports for Cult of Mac.

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“The signal bars on your iPhone will be replaced by a number,” Martin reports. “The higher the numeric portion of the negative number gets the worse your signal is. For example, -100 is worse than -79.”

Martin reports, “If you tap on the displayed number the display toggles between displaying the number and the normal signal bars.”

Read more in the full article here.

43 Comments

  1. Well, apparently, -95dBm should give you consistently reliable service. This being digital, the variation in signal strength should make absolutely no difference in quality of audio, or data throughput, as long as the signal is consistently at or above -95dBm. In other words, if you have bad audio, or slow data, and your signal is consistently above -95dBm, your bottleneck is elsewhere.

  2. Let me clarify this a bit; signal strength below -95dBm doesn’t imply poor service; it only means that there is an increasingly greater chance of dropping packets, which translates to garbled (or dropped out) voice and slower and inconsistent data transfer.

  3. i believe that -57 (or is it -53 ?) is the BEST that the phone can possibly get. one bar drops off the screen at -119, so that is the WORST it will go.

    not real sure how this is useful for consumers though.

    it would be interesting if there was a way to just change out the bars for the numeric system permanently, instead of it only working while in the field test mode.

  4. As I understand it, cell towers have to ration power (signal strength) as the number of users increases. If that is indeed the case, then it would not surprise me if signal strength varied quite a bit over time, even at the same geographic location.

  5. @notahippie
    It gives you the actual number for the signal strength. That will hopefully quiet any remaining doubters regarding iPhone antenna performance who continue to insist that Apple merely masked a design flaw by playing games with the bars.

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