Apple letter about iPhone 4 • Hacker News Board

Re: Apple letter about iPhone 4

#91

Post by jsz0 » Fri, Jul 02, 2010, 2:57 PM UTC

yumraj wrote: post #49

Am I missing something here, but if there is a bug in how they calculate bars shouldn't it apply equally in all the cases. for example, if signal == some-weak-signal, then bars = 5 then, if signal == some-weak-signal - 1 (for example), then shouldn't bars = 4 instead of bars = 0 (or 1). This seems like horseshit to me. Though it seems people are buying this explanation, so as far is Apple is concerned, it worked.

Bars are a very basic representation of a complex set of logarithmic measurements. I don't think it's all that simple. They're probably doing something like a 95th-percentile calculation on top of that. You don't want to change the bar signal meter for every normal fluctuation in RF. Otherwise the bar meter would constantly be moving up and down all the time. From an RF perspective it's also not as simple as just looking at the signal level. You can have great signal levels and poor SNR for example.

Re: Apple letter about iPhone 4

#92

Post by imajes » Fri, Jul 02, 2010, 2:57 PM UTC

woodrow wrote: post #66

gte910h wrote: post #62

Earlier quoted context omitted.

Steve Jobs always writes colloquially. I can see that trickling down.

Sure. But, in my opinion at least, his "Thoughts on Flash" seemed much more carefully worded than this. Everyone refers to signal strength as the quantity of "bars" they have, so I suppose this is the colloquial way to write this. But sentences like "Their big drop in bars is because their high bars were never real in the first place." just boggles my mind that it made it through Apple PR. This is the same company th…

"Thoughts on Flash" would have gone through several lawyers, as there's a real chance of a serious lawsuit in that instance. This one would be more marketing driven and would probably only get a cursory review.

Re: Apple letter about iPhone 4

#93

Post by KirinDave » Fri, Jul 02, 2010, 2:58 PM UTC

shareme wrote: post #25

does not jive with my own exp using android, RIM, and Nokia..

In the anandtech iPhone review he has it compete with a Nexus One and can measure a significant (though smaller) signal drop with the Nexus One using the same grip. I imagine you could reproduce the problem with every phone of similar dimensions.

Re: Apple letter about iPhone 4

#94

Post by ttol » Fri, Jul 02, 2010, 3:00 PM UTC

grok2 wrote: post #83

It seems like Apple solved a "perceived" problem with their phone (it is probably a problem with all phones, but never so heavily publicized like for the iPhone4) by fixing the the source of that perception. Clever. But the solution doesn't really address the real complaint -- that holding the phone in some ways seemed to change the number of bars shown. It seems like overall the bars display will be conservative now…

Actually Apple seemed to have biased the iPhone's display of bars to show 5 bars when the signal falls in the top 50% of the range. As Gruber noted, the exposed antenna in iPhone 4 highlighted the downside to that issue -- when you're near the floor of the 50% range, you suddenly go down in bars dramatically.

So the fix is to make what was fake before, more accurate.

Source (from Gruber): http://fscked.co.uk/post/754590440/this-infographic-hopefull...

Re: Apple letter about iPhone 4

#95

Post by agotterer » Fri, Jul 02, 2010, 3:02 PM UTC

agotterer wrote: post #12

So you're also telling me that my 3G reception is actually worse then I had previous thought? All those places I get 4 bars are really 2? I guess this explains why I often got dropped calls when I have "full reception". Wonder why they didn't mention the proximity problem. From what I have heard that's actually more annoying then the signal issue.

It's also interesting that the fix is a few weeks away and you only have 30 days to return your phone (early adopters are already a week in). So basically if the fix doesn't make you feel better, you can get the iPhone 6 in two years.

Re: Apple letter about iPhone 4

#96

Post by ugh » Fri, Jul 02, 2010, 3:05 PM UTC

yumraj wrote: post #49

Am I missing something here, but if there is a bug in how they calculate bars shouldn't it apply equally in all the cases. for example, if signal == some-weak-signal, then bars = 5 then, if signal == some-weak-signal - 1 (for example), then shouldn't bars = 4 instead of bars = 0 (or 1). This seems like horseshit to me. Though it seems people are buying this explanation, so as far is Apple is concerned, it worked.

AnandTech looked into how the iPhone maps signal strength to bars: http://www.anandtech.com/show/3794/the-iphone-4-review/2 (scroll down to the bar chart)

A 30 dB drop can both not change how many bars are displayed at all or get you down to no bars at all. If you have a signal strength between -51 dB and -61 dB and the signal drops 30 dB five bars will still be displayed. If you have a signal strength between -83 dB and -91 dB and the signal drops 30 dB you go all the way from five bars to zero bars.

What AnandTech found seems consistent with what Apple writes. More or less, at least. The drop in signal strength when holding the phone is a bit larger than with other phones (and previous iPhones), but not dramatically so. That’s the only thing Apple is still quiet about.

Re: Apple letter about iPhone 4

#97

Post by jaaron » Fri, Jul 02, 2010, 3:07 PM UTC

dailyrorschach wrote: post #55

ZeroGravitas wrote: post #7

This doesn't seem to jive with AnandTech's testing which ignored the bars completely and installed some software to read the signal strength directly. Their conclusion was that the iPhone 4 had better reception overall than the 3GS for various reasons, (a fact which Apple seem to be clinging to like a life raft) but that the external antennae was still faulty even when held "normally" and if fixed would make a major…

It seemed to me to actually jive with AnandTech's testing, and with user experience with the holding problem occurring in already weak signal areas. To wit many report that they only have the full drop in some places. As for holding the phone, I'm not so troubled by the antennae, could it be better, yes, but is it that terrible, doesn't seem so.

My thoughts as well. The Apple article seems to be saying exactly what the AnandTech article said:

    However, in locales that have less signal, but where iOS 
    still displays 5 bars, the drop of 24 dB is visualized 
    much differently. For example, at another test location, 
    signal without holding the phone is -89 dBm, which is 
    still displayed as 5 bars. Cup the phone, and you'll fall 
    all the way to -113 dBm. All the bars dramatically 
    disappear one after the other, people think they've 
    dramatically lost all the signal, and you know the rest...

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

Re: Apple letter about iPhone 4

#98

Post by proee » Fri, Jul 02, 2010, 3:07 PM UTC

This is going to make AT&T look even worse. Maybe apple knew this algorithm was in place all along and now they are telling AT&T that they can't play games anymore.

Apple is now placing the blame on AT&T by saying that the problem is actually low bars (i.e. the network).

Brilliant way to shift the blame.

Re: Apple letter about iPhone 4

#99

Post by jmackinn » Fri, Jul 02, 2010, 3:07 PM UTC

sounddust wrote: post #56

ZeroGravitas wrote: post #35

Earlier quoted context omitted.

Anand doesn't mention it explicitly, and neither do you, but I'm assuming that signal to noise ratio drops when you short the iPhone 4 antennae too otherwise his conclusion doesn't make sense: "At the end of the day, Apple should add an insulative coating to the stainless steel band, or subsidize bumper cases. It's that simple."

The problem is that Anandtech's conclusion is out of place with the rest of their article, even if you take into consideration the shorting of the antennae. The iPhone 4 loses 24.6dB of signal strength when cupped at the bottom vs 17.7dB for the Nexus one. If Apple should be required to add an insulative coating to the stainless steel, then shouldn't Google also be required to make their phone thicker (or make other…

What does the Nexus One have to do with the iPhone's antenna issue? There is no oversite body that is 'requiring' anyone to do anything. It's not Nexus One owners that are complaining about the antenna issue, it's iPhone users.

Re: Apple letter about iPhone 4

#100

Post by ttol » Fri, Jul 02, 2010, 3:13 PM UTC

joblessjunkie wrote: post #43

I actually believe them. I can't recall ever seeing my iPhone report 2 or 3 bars -- it's always a very low or very high signal indication. And yet, so many times I've gotten bad performances at "full signal"...

This is because right now, ~50% of the range = 5 bars. See: http://fscked.co.uk/post/754590440/this-infographic-hopefull...