iPhone 4 antenna probe finds flaws, improvements | iLounge News


iPhone 4 antenna probe finds flaws, improvements


As part of its iPhone 4 review, AnandTech took an in-depth look at the iPhone 4’s antenna and its signal issues, finding that “cupping the bottom left corner and making skin contact between the two antennas does result in a measurable difference in cellular reception,” but adding, “RF is a strange beast.” According to the review, standard signal strength for a UMTS 3G phone can range from -51 dBm—standing underneath or extremely close to the tower—to -113 dBm, the lowest amount of signal the phone can have before disconnecting entirely. Interestingly, AnandTech found that the iPhone 4’s bars map signal differently than one might expect, with more than 40% of the range of possible signal levels—from -99 dBm to -51 dBm—reported as five bars. The four bars indicator begins at roughly -99 to -101 dBm and three bars at -103 dBm, with two bars extending down to -107 dBm, and one bar covering all signals lower than that.

Based on AnandTech’s tests, the iPhone 4 exhibits a maximum signal drop of 24 dBm when held in the left hand and crossing the black strip at the bottom with the palm. When held naturally, but without making contact with the open palm, a drop of nearly 20 dBm was seen; when held naturally inside a case, that number dropped to 7 dBm. For comparison, the iPhone 3GS experienced drops of 14 dBm, 1.9 dBm, and 3.2 dBm, while the Google Nexus One scored losses of 18 dBm, 11 dBm, and 8 dBm, respectively. Despite the drops, the review finds that the iPhone 4’s antenna is actually improved from the iPhone 3GS, with the new handset showing an improved ability to perform calls and receive/send data when at the one bar signal level, and when encased, it was able to find and/or hold on to a signal in spots where the iPhone 3GS failed to find to do either.

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Well, well, well.
I’ve had nothing but positive experiences with my new iPhone 4.  Nary a dropped call.  The phone sometimes exhibits some loss of bars when held in the manner described, but it’s not consistently the same.  Nor is it as dramatic as the initial video (showing the bars dropping like you went into a tunnel).

Posted by jkoz73 on July 1, 2010 at 11:56 AM (CDT)


iPhone 4 has reception problems?

Posted by VULTR3 on July 1, 2010 at 12:53 PM (CDT)


This makes for a potent 1-2 punch.  Up to a 24 dBm loss based upon how the iPhone is held coupled with AT&T’s network issues.  Nobody will catch a break.

Posted by Charles Farley on July 1, 2010 at 12:55 PM (CDT)


While a 24dB loss when touching the antenna sounds like a lot, what really matters is (a) what power level the receiver loses connection compared to other phones, and (b) how much attenuation is caused by holding the phone, as compared to other phones.  If you want an Apples-to-Apples comparison one would have to make these same measurements on the iPhone 3G/GS. Could all this excitement be due to a very non-linear signal gauge, coupled with spotty AT&T coverage to begin with?

Posted by rockmyplimsoul on July 1, 2010 at 1:23 PM (CDT)


#4, AnandTech actually did include some comparison numbers in their report - I’ve added them to the above post.

Posted by Charles Starrett on July 1, 2010 at 2:56 PM (CDT)


While the problem doesn’t appear to be horribly different than other phones experience, Apple is having a PR problem in that their response to it has been flippant and comes off as arrogant. 

“Don’t hold it that way” is not a solution, nor is making excuses about how everyone else does it.  Obviously their engineers tested the things in and around the SF Bay Area, and they experience the signal attenuation and call drops themselves, hence the bumper case that seems perfectly designed to keep the antenna out of contact with your palm.  I’m having real second thoughts about buying one.  At this point, I wasn’t able to preorder do to AT&T screw ups, and the account type I’m on means I can’t get one at an Apple store.  I’m off contract and wondering if I should get a new Android phone instead.  And I’ll have a while to think about it, since I can’t by either the iPhone 4 or a good Android from AT&T yet.

Posted by Dan on July 1, 2010 at 6:24 PM (CDT)


Thanks for the test, you just change my decision to return the iphone4 and keep the old 3gs. Can you please do more test with different phone.

Posted by Jimmy on July 1, 2010 at 6:32 PM (CDT)


Has anybody tested or experienced an ACTUAL increase of dropped calls or inability to grab a signal?  The report states that even though the new iPhone shows a greater signal drop, its ability to hold a signal is better than the 3GS.  I can attest to that claim as I’ve had no dropped calls in a week with the new iPhone (I have nothing covering the antennas).  My old 3G would have experience at least one or two in that same time period.  I’m not saying I’ll never experience a dropped call (it IS AT&T, after all), but my experience has been excellent since I’ve gotten the new phone.
I agree with #6, Dan, that the response from Apple was less than stellar.  Even if the reception of the new iPhone IS better, Steve-o should have probably tempered his flippant response.  It does come off arrogant.
My $0.02, anyway.

Posted by jkoz73 on July 2, 2010 at 9:46 AM (CDT)

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