Better at the Low End, Mixed Feelings Everywhere Else

Brian came up with the plan to enable the numerical signal strength visualization and executed on it very well in our original iPhone 4 review. Since then there’s been a disturbing amount of debate as to whether or not this actually amounts to a problem with the phone.

Part of the confusion stems from the fact that doing this sort of antenna testing in a real world scenario is time intensive. As Brian mentioned on the previous page, for today’s article both of us were driving around our respective cities, stopping at various locations, measuring signal strength and comparing it to bar mappings in order to produce the charts you saw on the other page.

There’s no denying that Apple has played a significant role in why there continues to be debate about the iPhone 4 antenna. By simply addressing the pre-4.0.1 bars not being a good representation of signal strength and ignoring the fact that the iPhone 4 does lose more signal strength than competing phones depending on how you hold it, Apple manages to convince its faithful that there’s nothing wrong while driving its critics to demand a recall.

My mother always taught me that honesty is the best policy and presumably I’m not the only one in the world who was privy to this information. Had Apple come clean with both of these facts (the bar mapping and the signal attenuation issue) early on we’d be in a far more clear cut world today.

We have consistently argued that the 4’s antenna is a design choice by Apple. As we’ve seen in our testing there are situations where the iPhone 4’s antenna makes things better (e.g. holding onto calls with very low signal strength) and other situations where the design makes them worse (e.g. holding it wrong in situations with low signal strength). I wanted to describe the inconsistency in greater detail so I went out with an iPhone 3GS and 4 and documented my experiences.

In practice I found three things that were true about the iPhone 4’s antenna behavior compared to the 3GS.

Reception in average conditions is sometimes significantly better on the iPhone 4 than on the 3GS. Take a look at the image capture below. In the same exact location we have better reception on the 4 than the 3GS. Granted this could be due to a number of variables outside of the phone’s antenna itself, but it happened enough times that it’s worth reporting. This is the positive to Apple’s external antenna design - you can and do get better reception. Unfortunately the tradeoff is the scenario I just described before this.

iPhone 4 (left) at -81 dBm vs. iPhone 3GS (right) at -94 dBm

Signal strength is sometimes the same as or worse than the iPhone 3GS. This is really where the problem comes into play. In the shot below I have the 4 and 3GS sitting next to one another and they are displaying roughly the same signal strength. We’ve already proven that holding the iPhone 4 attenuates its signal more than the 3GS, which results in the frustration we’ve seen expressed by many at this point. In situations where the 4 has the same signal as the 3GS, holding the phone is going to drop it to levels significantly worse than the 3GS. If you’re in an area with low signal strength to begin with, holding the phone is going to bring you down to dangerously low levels.

iPhone 4 (left) at -103 dBm vs. iPhone 3GS (right) at -104 dBm

iPhone 4 being held tightly (left) at -115 dBm vs. iPhone 3GS being held tightly (right) at -107 dBm

iPhone 4 (left) at -77 dBm vs. iPhone 3GS (right) at -66 dBm

The iPhone 4 is better at holding onto calls and data at very low signal levels. We’ve mentioned this one before but it’s worth reiterating. The new antenna does let me make calls and transmit data at very low signal strength. With the iOS 4.0.1 update I was able to make a call at -115dB on the 3GS, however the call did drop within a minute of starting it. By comparison I was able to have a much longer conversation without dropping the call at -120dB on the 4. By no means is this a scientific comparison, but anecdotally both Brian and I feel that the low signal strength performance of the iPhone 4 is better than the 3GS.

A call at -120 dBm on the iPhone 4

If you’re keeping tabs you’ll note that this is what is traditionally referred to as a trade off. Apple opted for good performance in low signal situations (and style of course) over maintaining consistently better or unchanged radio performance compared to the 3GS. I would personally consider this to be an unnecessarily risky design choice, particularly for a smartphone vendor. Note that it's nearly impossible to separate out the antenna from the rest of the iPhone 4 platform to determine exactly what is responsible for the phone's signal sensitivity in various situations. All we ultimately know is how physically interacting with the antenna impacts reported signal strength.

I can’t stress enough that this issue impacts all users. The variability is in how strong of a signal you have to begin with. That’s the absolute only reason there’s debate in these discussions from phone to phone. At my desk I don’t get great reception on AT&T. With the iPhone 4 I’m usually at -96dBm. If I keep a tight grip on the phone or if I’m holding it to send text messages I can sometimes lose all signal entirely. This is a combination of poor reception at my house and the fact that the 4 loses more of its signal than other phones when held certain ways.

Brian on the other hand has much better reception at his home. To him, the signal strength drops but it does not drop enough for this to be a problem. I consider myself to be on the border. If I’m mindful of how I’m holding the phone it’s not an issue, and even most of the time if I’m not paying attention to it it’s not an issue. However there are definitely times when it does become a problem. I wouldn’t consider it to be the majority of the time or even more than 10% of the time, but it happens enough for me to have to think about it. Ultimately this is why I consider Apple’s design here to be unnecessarily risky. Introducing a change with stylistic and technical benefits where the downside is limited but potentially very noticeable is just ballsy.

Luckily for Apple, there are things that can be done about it.

The Bars Have Changed Mitigating the Problem with Tape/Gloves


View All Comments

  • SharksFan - Monday, July 19, 2010 - link

    They probably just read the article and realized they were as well off with an iPhone 4 signal wise vs the compared Nexus One, so they stopped worrying.

    -121db cutoff and -24 signal attentuation means the phone should be good till -97db on average, before you grab it hard.

    -121 cutoff and -20 signal attenuation means the phone should be good till -101db on average.

    -97db vs -98db when compared to Nexus One when held "hard", and -101 v -102 when compared to Nexus One when held "normally".

    Those are pretty much identical cutoff's btw.

    So I guess you should be clamoring for a Nexus One recall too....

    Maybe we can sue Google?
  • leexgx - Friday, July 16, 2010 - link

    i did not even read that comment Reply
  • gilesrulz - Friday, July 16, 2010 - link

    First, thank you for your two well reasoned and reported articles on this subject. Would you be willing to update the article to discuss Apple's indication that attenuation caused by conductivity is not the issue, and that it is caused by the normal physics of being meat bags? Reply
  • steve.h - Monday, July 19, 2010 - link

    Yes! This is exactly what I am also wondering, and something I haven't seen addressed anywhere else. If the problem is mostly due to the conductivity of the skin interfering with the antenna, Apple hasn't been completely truthful in comparing their problems with problems faced by other manufacturers. It seems like a fairly simple test to perform, I am surprised none of the tech blogs I read have tried to address this yet. Of course anandtech is the only place any actual information gathering was done and reported in the first place, most of the rest was just fear mongering.

    Again, I am convinced that this is a non-issue either way for most users, since it only affects performance in a small number of cases. However, I'd be interested to see if Apple really was being intentionally misleading in their press conference by comparing their issues to other manufacturers.
  • atomez - Friday, July 16, 2010 - link

    I got an iPhone 3G with OS4 (iPhone 4 no yet available here) and the same "grip of deat" happens! It usually got 5 bars signal strenght. Using the left hand GOD it dropped to 2 bars. Now with OS4.1 it shows 3 bars and drops to the same 2 bars on GOD. And you know what? It never dropped a call! So it's working fine for me. I understand the iPhone 4 will be the same.

    It's not a problem, it's a feature. Get used to it.

    No one is fooling you. If you don't like it, just don't buy it. If you have it, go get the free bumper. Or just return it and get your money back.
  • Polakapalooza - Friday, July 16, 2010 - link

    Essentially, then, you are equating — and, it appears, correctly so — the iPhone 4 with Henry Wadsworth Longfellow's "little girl," to wit:

    There was a little girl,
    Who had a little curl,
    Right in the middle of her forehead.
    When she was good,
    She was very good indeed,
    But when she was bad she was horrid.
  • jms102285 - Friday, July 16, 2010 - link

    Might I recommend to the readers who are upset at the passive-apple/anti-MS dynamic here an alternative:

    For the past few years I have been coming here for the news on the latest/greatest reviews digging into the meat and potatoes of cutting edge hardware. Lately I've been very very disappointed at the disproportionate amount of content regarding Apple vs. the release of other new phones.

    I understand that website hits lead to more advertising revenue and that Apple news gets hits, but couple that with the dare I say passive nature towards Apples mistakes versus other manufacturers' mistakes and it really hurts the integrity of what I come here for.

    I also have been less than happy with the IT computing section as they really don't discuss much there. It seems like an afterthought compared to other sections of the site.

    So peace out Anand, good luck here.
  • SunSamurai - Friday, July 16, 2010 - link

    You wont be missed.

    Running off because of one too many apple related articles. Talk about childish.
  • screensurfer - Friday, July 16, 2010 - link

    Just a few of things I noticed:

    1) Apple found 3 phones that have similar problems. Fine. I can find a dozen that don't have such "grave" problem. The problem with iPhone 4 is that its attenuation is "a record" for a smartphone when the hand touches it.

    2) Apple took 22 days to find that the solution... is to patch it with a case. Bah!

    3) AppleCare data: it's flawed in 2 ways: First, they should only present it when the 30 days are over, to have a more apples-to-apples comparison vs. 3GS (who's data might not be the same time period). Second, the fact that iPhone 4 is a much better device than 3GS: people are holding to them. Regardless, this is not an excuse to keep a design flaw.

    4) ATT returns rate only. Where are Apple stores numbers? Could they show a different figure? I believe so, otherwise Steve would have shown their own numbers.

    5) (My favorite lie with numbers technique): Average cell phone drops 1 call per 100. If iPhone4 drops <1 pp more than 3GS, it means that it drops up to more 100% more calls than 3GS!!!!!!!

    6) They have figured out a better hardware that prevents this, they're just unwilling to recall the inicial production. Why? First, 30th September deadline; second, Steve implied it during the presentation that they were working on a hardware fix that "defies physics".

    Please don't lie with numbers. I hope this helps to clarify the PR BS!
  • Snotling - Friday, July 16, 2010 - link

    "Steve implied it during the presentation that they were working on a hardware fix that "defies physics"."

    yeah, I'm sure Steve Jobs will try hard to defeat the laws of physics...

    do you realize how silly you sound?

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