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

[Dave Farber <dave () farber net>]

Begin forwarded message:

> From: David Josephson <dlj04 () josephson com>
> Date: July 15, 2010 1:44:23 AM EDT
> To: dave () farber net
> Subject: Re: [IP] re  Engineer Claims Consumer Reports iPhone 4 Reception Problem Study Is Flawed - iPhone Hacks

> Dave,
>
> There are a number of red herrings and men behind the curtain in this discussion of the iPhone antenna and the 
> Consumers Reports tests.
>
> First, Consumers Reports' anechoic chamber seems to be acoustically anechoic, intended for testing sound (speakers, 
> vacuum cleaners etc.) While they might look similar to electromagnetic anechoic chambers, they aren't at all the same 
> (we make microphones, we have an acoustic one, and we rent time in an electromagnetic one when we want to test RF) 
> and it's highly unlikely that one would magically be useful both for sound and RF. There are well established tests 
> for determining the effectiveness of anechoic chambers for sound and RF, and I have not seen one that does both.
>
> One of the primary design goals in making a wireless handset is the reduction of reported specific absorption rate 
> (SAR), or the RF radiation to which a user is theoretically exposed while using it. To put it politely, SAR testing 
> as mandated by FCC (and as reported on FCC OET's own web page) is flawed in that the handset is strapped to a model 
> head without a hand being in place to hold it there. The presence of a hand significantly impacts the radiated power 
> of the phone. It is only a guess, but I would guess that if there is in fact lower than optimal transmitted power, it 
> might be due to design decisions intended to reduce SAR. Cell phone radiation as a health risk remains an open 
> question (there seems to be no dose-response relationship at the levels experienced by cell phone users) but this 
> doesn't prevent people from assuming that lower SAR is better, and therefore pressuring handset makers to produce 
> devices that transmit less power toward the head -- as measured by a test that doesn't include a hand holding the 
> device.
>
> --
> David Josephson
> Josephson Engineering



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