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An Engineer Fails the Consumer Report Test

This is from this blog - http://mobileanalyst.wordpress.com/2010/07/12/iphone-4-report-consumer-reports-s tudy-is-full-of-crap/
I pass it on to bring another side to the story.
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Consumer Report iPhone4 study flawed
Posted on July 12, 2010 by Bob
Let me start off by saying that for much of my career, I worked as an electromagnetic engineer working on exactly the kind of issues that now face Apple on the iPhone4. But this isn’t about me. It is about Consumer Reports and its not so scientific testing on the iPhone 4.

Consumer reports “RF” engineers should know better than to think they can run an engineering grade test for an issue like this in a shielded room. And certainly not one with people in it.

To even reasonably run a scientific test, the iPhone should have been sitting on a non-metallic pedestal inside an anechoic chamber. The base station simulator should have been also sitting outside the chamber and had a calibrated antenna plumbed to it from inside the chamber.

I have not seen CR’s claim directly that the finger effect reduces the iPhones sensitivity by 20db as reported elsewhere, but unless CR connected to a functional point inside the iPhone that number is fantasy. Even the way they seemed to have tested the change by varying the base station simulator seems assume the iPhone receiver and/or transmitter operate in a linear fashion (the same way) across all signal strengths – bad assumption.

Bottom line. From what I can see in the reports, Consumer Reports replicated the same uncontrolled, unscientific experiments that many of the blogging sites have done.

I’m not saying that Apple has no h/w problem and they surely have a s/w issue. But I’m still wondering that if the software signal algorithm was not AFU’d in the first place how many if anyone would talking about this “problem”

I also don’t know what part of this problem is Apple’s and what part is related to the AT&T network.

And we don’t know how the observed effect is, or is not similar to other devices.

We also don’t know if placing a finger on the antenna bridge is detuning the antenna or detuning the receiver itself.

And neither does Consumer Reports.

Oh. Mr Job’s; right now. Silence is not golden. I’m quite sure Apple has these answers by now… If not, send me a few more iPhones, I’ll find a chamber and get you some answers in a day.

Ps. Blogged from my Iphone4 in a rest area on my way home from work, cause I just couldn’t help myself!
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Dell Intel quad core Win7 - 27" iMac I5, Mac OS X (10.6.4), MacMini - iPhone 3G - iPhone 4

Posted on Jul 12, 2010 8:04 PM

69 replies

tharger

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Jul 12, 2010 9:19 PM in response to Dan Slocum

I agree. But my guess is that they can't.

MrCourtney Author

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Jul 12, 2010 10:06 PM in response to tharger

Folks -

There's lots of threads where you can vent your frustration. It would be to everyone's advantage if you could get back to an engineering discussion on whether CR's testing was sound or not.

Jul 12, 2010 10:37 PM in response to MrCourtney

MrCourtney wrote:
Folks -

There's lots of threads where you can vent your frustration. It would be to everyone's advantage if you could get back to an engineering discussion on whether CR's testing was sound or not.

CR engineer is right
Blog dude is right, but his testing is a way AROUND the issue as it will just test the reception based on signal strength rather than rely on the iPhone antenna.

In other words, CR engineer = real world testing
If you have 8 Grand to drop on testing equipment that CR uses, then buy this:
http://www.ramayes.com/UsedTest_Equipment_forSale.htm

MrCourtney Author

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Jul 12, 2010 10:43 PM in response to ChristianM19

Blog dude is right, but his testing is a way AROUND the issue as it will just test the reception based on signal strength rather than rely on the iPhone antenna.

Interesting. SInce is not my area of engineering experise - would you expand on your conclusions?

modular747

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Jul 12, 2010 10:54 PM in response to ChristianM19

CR engineer is right
Blog dude is right, but his testing is a way AROUND the issue as it will just test the reception based on signal strength rather than rely on the iPhone antenna.

No, the "blog dude" is proposing testing that removes extraneous factors and unwarranted assumptions from the test. It better isolates the problem with the antenna, and is more scientifically rigorous. For all we know, it will give the same results as the CU test.

MrCourtney Author

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Jul 12, 2010 10:49 PM in response to modular747

That was my reading too.

iSilver

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Jul 12, 2010 11:07 PM in response to MrCourtney

MrCourtney wrote:
To even reasonably run a scientific test, the iPhone should have been sitting on a non-metallic pedestal inside an anechoic chamber. The base station simulator should have been also sitting outside the chamber and had a calibrated antenna plumbed to it from inside the chamber.

================

Spoken like a true engineer - one would imagine Apple did these sorts of tests but how they work in the chamber doesn't really matter if the phone doesn't work when it's in the hands of the consumers.

I suppose most iPhone users stroll down to their closest anechoic chamber so they can make a phone call. Is there a charge for that? Oh, by the way, do you know where my local anechoic chamber is?

modular747

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Jul 12, 2010 11:17 PM in response to iSilver

You obviously have no clue how or why engineering test are performed.

Jul 12, 2010 11:20 PM in response to modular747

modular747 wrote:
You obviously have no clue how or why engineering test are performed.

Enlighten us. I thought the Consumer Reports engineer explained it in a conversational, intelligent and thoughtful way.

The iPhone 4, sadly, has a significant hardware issue. What do you propose?

Jul 12, 2010 11:37 PM in response to modular747

This whole blog is ridiculous. There is definitely an issue with the antenna. This is a fact that is slowly but surely becoming accepted. The reason we know how much db is lost is because of the testing that AnandTech did. Here is the link, it's a great read.

http://www.anandtech.com/show/3794/the-iphone-4-review/2

Anyway, for those who don't read the article the tester was able to get a db reading instead of bars. EDIT: I had a quote here but it mentioned some stuff I don't believe is allowed here so I removed it. Just read the article if you're curious as to how he got a db reading.

When he held the phone, covering the black line, he lost 24db. He did these tests over and over and took an average. This sounds like a true test to me. We don't need a lab to figure this stuff out. How many of us use our phone in lab conditions?

I've been saying this next part over and over but I know that every time I post this a few new people get to see it. For those of you saying you don't have an issue please read and understand this. The article explains this but if you are in an area with great reception you will never notice any problems. The best possible signal is -51db. If you are getting -65db, a loss of 24db will put you at -89db. Guess what? The cut off for 5 bars is around -91db so you will never see a drop in bars. Anyone not reporting an issue must be getting a signal of -67db or better. Please tell me this is making sense.

All the software update will do as far as the display of the bars is remap the bars to different db ranges. By the way, this is not speculation or rumor. Apple has stated that the calculation is off for the display of bars. After the update it will take a stronger signal to maintain 5 bars. For example, maybe they will move the 5 bar cutoff to -70 or -75. This will fix the "dramatic decrease in bars" since going from 3 bars to no signal isn't as "dramatic" as going from 5 bars to no signal. Most likely after the update, nobody will lose signal in a 5 bar area. In turn, many people used to seeing 5 bars in an area will only see 3 or 4 in that area.

I find it funny that Apple is "surprised" that their db calculations are wrong since they are the ones who remapped the bars a couple of years ago to give more people 5 bars. Now they can just put the db ranges back where they were originally and start pointing the finger at AT&T when people wonder why they don't have 5 bars.

Message was edited by: Stevenam81

modular747

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Jul 12, 2010 11:31 PM in response to Dan Slocum

Your idea of an engineering test appears to be one that produces the results you want to hear, and becomes by your definition, "intelligent." The problem with the CU test as explained by the "blog guy" is that it introduced extraneous factors and didn't assumed linear effect in the iPhone 4 antenna/receiver at different signal levels. The test he proposed tries to eliminate those variables. As I said, it probably will show the same results, but the results will be more meaningful.

Jul 12, 2010 11:34 PM in response to modular747

modular747 wrote:
Your idea of an engineering test appears to be one that produces the results you want to hear, and becomes by your definition, "intelligent." The problem with the CU test as explained by the "blog guy" is that it introduced extraneous factors and didn't assumed linear effect in the iPhone 4 antenna/receiver at different signal levels. The test he proposed tries to eliminate those variables. As I said, it probably will show the same results, but the results will be more meaningful.

Blah blah blah. The phone will have to be fixed. The rest is noise. A lot of it FROM you.

Accept the flaw and let's get a solution from Apple.

modular747

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Jul 12, 2010 11:37 PM in response to Stevenam81

If you read some other threads, I discussed the anandteck tests, more than week ago. The weakness of that test is that it relies on the iPhone's own internal measurement of signal strength which may very well be inaccurate. The CU and other test proposed use an external measurement of signal strength in isolated conditions.

Jul 12, 2010 11:40 PM in response to modular747

modular747 wrote:
If you read some other threads, I discussed the anandteck tests, more than week ago. The weakness of that test is that it relies on the iPhone's own internal measurement of signal strength which may very well be inaccurate. The CU and other test proposed use an external measurement of signal strength in isolated conditions.

The FIX?

modular747

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Jul 12, 2010 11:44 PM in response to Dan Slocum

Dan Slocum wrote:
Blah blah blah. The phone will have to be fixed. The rest is noise. A lot of it FROM you.

Is that the best you can come up with - does it impress your herd? Noise? That's a laugh coming from you. About a 3rd of the posts in this forum complaining about the "antenna" come from you and your buddy. The only thing you want is to bully everyone into joining in. You have no clue what I'm saying,

An Engineer Fails the Consumer Report Test