re Engineer Claims Consumer Reports iPhone 4 Reception Problem Study Is Flawed - iPhone Hacks

[Dave Farber <dave () farber net>]

Begin forwarded message:

> From: "DeGraff, Kenneth" <kenneth.degraff () mail house gov>
> Date: July 14, 2010 7:32:46 PM EDT
> To: dave () farber net, dpreed () reed com
> Subject: Re: [IP] re  Engineer Claims Consumer Reports iPhone 4 Reception Problem Study Is Flawed - iPhone Hacks

> For what it's worth, as a former employee of the non-profit publisher of Consumer Reports, their labs in Yonkers, NY 
> have such an anechoic chamber on an independent foundation. 
>
> They built it for speakers, but it works in this case -- as the pundit would have discovered if he had read the info 
> they made public on their website. Inside the cage, they connected to a base station simulator commonly used in the 
> wireless industry for testing handsets. I would be surprised if they didn't use repeatable real-world-style testing 
> as well. 
>
> But Consumer Reports is definitely not the kind of operation that would simply take some bloggers' assertions and run 
> with them as their own. Their reputation is too important to them. 
>
> =-=-=-=-=-=-=-=-=-=-=-=-=-=-= 
> Kenneth DeGraff 
> Legislative Director 
> Office of Congressman Mike Doyle
>
> From: Dave Farber <dave () farber net> 
> To: ip <ip () v2 listbox com> 
> Sent: Wed Jul 14 18:21:19 2010
> Subject: [IP] re Engineer Claims Consumer Reports iPhone 4 Reception Problem Study Is Flawed - iPhone Hacks 
>
>
>
>
>
> Begin forwarded message:
>
> > From: "David P. Reed" <dpreed () reed com>
> > Date: July 14, 2010 3:05:06 PM EDT
> > To: dave () farber net
> > Cc: ip <ip () v2 listbox com>
> > Subject: Re: [IP] Engineer Claims Consumer Reports iPhone 4 Reception Problem Study Is Flawed - iPhone Hacks
>
> > Two points made by Bob Egan, the "electromagnetic engineer" who disputes the claim, trouble me a bit.  Besides that, 
> > his words seem to indicate that he has not actually read the Consumer Reports *report* itself.   A scientist would 
> > not claim the testing was wrong if he had not studied the data first.  However, without trying to claim that Egan or 
> > CR are right or wrong, here's what worries me about Egan's post (as quoted in the iphonehack site, there being no 
> > url to his original).
> >
> > 1. the iPhone 4's *antenna* is actually on the outside of the phone, capable of coupling with the human hand.  There 
> > is no dispute about that.  So why is Egan claiming that 20 dB of sensitivity reduction is "fantasy" because they 
> > don't connect to a functional test point inside the phone?  Is he claiming that touching an antenna cannot cause 
> > signal strength to drop 20dB or more?  I just tried grabbing an antenna firmly in my hand that is atached on a 900 
> > MHz SDR receiver I happen to have set up in my lab at home, and the signal dropped as much as 40dB ...  Perhaps he 
> > is just saying that he wants a more precise test to give the exact number?  What if it turns out to be 40 dB in some 
> > cases and not 20 dB?  Was CR wrong in that case?
> >
> > 2. Much is made by Evans of the need for an anechoic chamber isolated from outside influences.   Hmm... do you use 
> > your phone in an anechoic chamber?   Is your body (a conductive sack of salt water) not in contact with the phone?  
> > What about the car you are sitting in when you use the phone?  Hmm... I think CR's test might have been *better* 
> > than a "scientific" test in an anechoic chamber, or at least one could argue that.
> >
> > I'm sure that sensitivity tests with "functional test points" are done during manufacturing of the phone.  
> > Presumably the effect is not observed in the manufacturing process.  So repeating the same test done during 
> > manufacturing proves nothing other than "the phone met its test specs".
> >
> > In the end of the day, science and engineering are not about experiments in the "lab".  We design products for and 
> > study *reality*.  Labs are just ways to set up simplistic cases, and are quite useful for that - but most scientists 
> > realize that to run a test in isolation risks missing really important effects, and most design engineers do also.
> >
> > On 07/14/2010 12:48 PM, Dave Farber wrote:
> > > http://www.iphonehacks.com/2010/07/radio-engineer-claims-consumer-reports-iphone-4-reception-problem-study-is-flawed.html
> > >
> > >
> > > Btw I have found no reception issues with my iPhone 4 with or without a case. I do find a face proximity problem 
> > > infrequently 
> > >
> > > Dave
> > >
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