Below is a comment from maati on this engadget article. Huzzah science. My sister still hasn’t gotten her iPhone 4 so I still don’t have first hand impressions.
@bighap Apple failed.
And they’re lying about the nature of the problem.
No other phone suffers from the same issues.
Here are the facts, the real ones:
Anandtech has shown that the Nexus One’s signal drops by only 10dBm when holding it normally, while the iPhone 4’s signal drops by 24dBm.
Even when gripped tightly, the Nexus One’s signal drops by only 17dBm, compared to 24dBm on the iPhone. And of course, nobody holds his phone like that in normal use.
CNET have done a video that has shown that, even when the iPhone 4 has 5 bars, by just touching the weak spot, the person on the other end can’t hear you anymore.
German Stiftung Warentest have done scientific testing and seen the iPhone 4’s reception drop by 90% when the weak spot gets touched.
They could not make other phones drop more than 25%, even when gripping them tightly.
Steve Jobs himself has confirmed that the iPhone 4 drops up to one more call per 100 than the 3GS (it must be very close to one, otherwise he would have used other numbers). AT&T’s average dropped call rate is 1.44%, they claim.
If the iPhone 3GS is an ‘average’ AT&T phone, that means the iPhone 4 drops about 67% more calls than the 3GS. A HUGE increase!
The real issue is not that you can make the signal drop, but HOW and by HOW MUCH.
HOW: Hold the iPhone 4 naturally in your left hand, like everyone does while surfing or making left-handed calls.
That’s very different from ‘death-gripping’.
HOW MUCH: 20dBm vs. 10dBm or 90% vs. 25% or 99% vs. 90%, depending on your system of measurement. Or, in other words: Much more than with other phones.
And I can even explain to you WHY the iPhone has those problems and other phones don’t.
The iPhone 4 is the only phone that lets yoou ground the antenna by bridging it with other metal parts.
Other phones let you shield the antenna, which of course causes attenuation. A drop of 10dBm means power drops by a factor of 10, or 90%.
But that’s very different to grounding the antenna, which causes it to become completely ineffective. A drop of 20dBm means power drops by a factor of 100, or 99%.
That means, if you hold both phones naturally, the Nexus One still recieves ten times the radiation power of the iPhone 4.
At -91dBm (the minimum for full 5 bars in iOS4.0), the Nexus One only shows 3 bars, but it can still easily make crystal clear calls when held naturally, even though it loses 10dBm, whereas the iPhone 4 gets very close to dropping the call, which happens at -113dBm.
Bars don’t mean anything. If one phone shows 4 bars at -90dBm and another shows 4 bars at -80dBm, the radiation power recieved by the first phone is still 90% less than that recieved by the latter.
By showing us bars, instead of doing real reception and audio quality measurements, Apple essentially admits that other phones don’t have any real issues