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Comment by IgorPartola | Hacker News Reader

I don't get it. People keep talking about the grip of death, etc. If you have an iPhone 4, hook up a length of wire between the two antennas and tell us if the bars drop immediately. As a bonus, go get a voltmeter or a scope and tell us exactly what's going on.

Yes, human body can conduct electricity, but your conductivity will depend on amongst other factors, your gender, age, body fat percentage, hydration level, etc. A piece of copper wire is not going to have these problems. So show us once and for all what's going on.

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here: http://www.youtube.com/watch?v=kgouzUMlQpY

paperclip vs iphone 4

The problem with that might be that copper normally doesn’t get near an iPhone. The results wouldn’t matter. (Beyond determining whether the steel is insulated or not. And we already know that.)

It would help to distinguish between (1) antenna detuning because of bridging between the antennas and (2) attenuation because of having a lump of human body next to the antenna. I don't know that that would be directly useful in itself, but it would be interesting. Obvious further experiments: what happens when you add some impedance (resistive and/or capacitive) to the connection between the antennas? what happens if you put a conductive thing, broadly similar to a human hand but better controlled, in various places near the antenna? Etc.

The results of doing a bunch of measurements like this could make it much easier to answer questions like: What is it about your hand or your grip or whatever that determines how much you impair reception on your iPhone? How much of the problem would go away if you put various things (kapton tape, rubber bumper, etc.) between the antenna and your hand?

Just playing around with actual human hands can give some information of that sort, and if you're only going to do a small amount of investigation you probably get more information that way. But for a deeper understanding of what's going on, you'd want to be more scientific and try harder to decouple different failure mechanisms.

(Of course talk is cheap. I haven't done any of that. Not least because I happen not to have an iPhone.)

> It would help to distinguish between (1) antenna detuning because of bridging between the antennas and (2) attenuation because of having a lump of human body next to the antenna.

It is, without doubt, #1. Any confusion stems from the variety of ways in which it can fail to happen (variable conductivity of people, for one), or fail to have dramatic results (being in an area with strong signal).

If you're sufficiently conductive, there's a good chance you can reproduce the problem by walking into an Apple store and trying your hand. That's what I did, and there was a dramatic difference between bridging both antennas with just an inch of finger vs covering the left antenna with as much palm as possible. That wiped out any remaining skepticism I might have had.

According to Anandtech's investigations -- http://www.anandtech.com/show/3794/the-iphone-4-review/2 -- both effects are real. #1 is the one that Apple seem to have screwed up on, and that might be fixable (to some extent at least) by putting something over some or all of the exposed metal of the antenna. #2 is the one that applies to other phones about as much as to the iPhone 4. Both will cause signal loss when you hold the phone, relative to sitting it on a table or whatever.

Right, I wasn't denying #2. I'm just saying there can be no doubt that #1 is real, and more severe by far under the right conditions.

What gjm11 said. I've read reports of both (1) and (2) being a problem. The idea that it's just shorting two antennas would is the more favorable since then "all" we'd have to do is insulate the antenna. It could also lead to all manner of fun conspiracy theories like the fact that Apple came up with the bumper cases late in the game because they knew that the first batch of the new phones would be defective and needed to provide some sort of a solution. If the problem is (2), I would not know how to solve it in any cheap manner (who knows maybe there is a way. For example car key fobs are specifically detuned and only get to the correct frequency if they are held by a human hand, thus using you as an antenna.)

EDIT: Also, we don't know if the steel is insulated. Has anyone tried to measure its resistance? For all we know it is insulated and the problem is (2).

Anandtech did at least some testing with a multimeter:

“Gizmodo reported (and iFixit followed up) on some users claiming that newer iPhone 4s had a different coating on their stainless steel band that mitigated the signal attenuation issue caused by tightly holding the phone.”

“We found an iPhone 4 produced in week 28 of 2010 (digits 4 & 5 from the left of the iPhone 4’s serial number indicate production week) and took a multimeter to it. There was no measurable difference in resistance between it and our older iPhone 4s. In other words, the band was just as conductive.”

My understanding is that all phones suffer #2, and the iPhone 4 is not obviously much worse in this respect than its rivals.

But, of course, even if you do something that fixes #1 completely, there will always be people saying "Boo, Apple hasn't fixed the problem! When I hold my phone like this, I get less signal, just as I did before!" -- when in fact the same would be true whatever phone they used.

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