[DBMandrake]

Apple has released iOS 4.0.1 for the iPhone which includes the much talked about recalibration of the bars to signal strength relationship. Anandtech has taken the time to measure the changes here:

http://www.anandtech.com/show/3821/iphone-4-redux-analyzing-apples-ios-41-signal-fix

Basically the 1-5 bar reading has been stretched out over a much wider signal range, giving a more progressive and useful reading. Typically this will mean that the phone will indicate less bars than before unless you have a really strong signal, but this is no cause for concern because the signal reception has not changed, only the indicated number of bars is changed. (No death grip fix here, although it will affect the way the bars change when gripping)

There are a few other bug fixes as well, hopefully they've fixed the low memory bug that I have been seeing on the 3GS where after a while the system runs low on memory and starts stuttering (both UI response and audio playback) instead of automatically killing old background tasks.

iPad 3.2.1 includes a fix to the Wifi DHCP issue where the iPad will continue to use an IP address after it has expired, plus a few other bug fixes.

Go get it! :)

[Ben]

Good news. Now we just need to wait and see what the 'emergency' press conference has to offer!

[DBMandrake]

Updated my 3GS to 4.0.1 and deliberately left the 3G on 4.0 for a comparison. My results on the 3GS agree with the alterations to the signal bars measured by Anandtech on an iPhone 4.

Indoors at home on Three it's gone from 5 bars occasionally flicking down to 4 bars, to 2 bars occasionally flicking down to 1 bar or up to 3 bars, so quite a substantial change in the number of indicated bars at the level of signal I receive. (Varying from -92dBm to -107dBm)

Between bars 2, 3, 4, and 5 there is now a linear progression of about 9dB per bar, as the Anandtech diagram shows. I do wonder if Apple has gone a bit too far in the other direction though - I would consider myself to be in a fairly good signal area (certainly calls are always perfect and data speeds are good no matter how the phone is held) and yet 2 bars is the average I see now - which to most consumers who haven't been following this whole signal reporting fiasco would seem unusually low.

To get a 5 bar signal now requires -76dBm which is a very strong signal - basically you'd have to be outdoors within about 50 metres of a mast to get this signal level, so I would be surprised if many people ever see 5 bars indicated on 3G after this change.

On the new scale I would describe the bars as follows - 1 weak signal, may drop out, 2 - decent signal, 3, 4, or 5 - strong signal.

It's unknown whether the bar calibration on 2G (which has always had a completely different calibration than 3G) has been altered in any way - although I haven't tested it, at a glance it looks like they've left that alone.

I really do wonder though what is going to happen on forums and in Genius bars when people update their OS, not noticing the subtle comments in the readme (who reads those except geeks anyway?) and not being up with the news, only to find their bar reading much lower ?

Or worse - people comparing phones with each other, some pre-update and some post-update, I can see a lot of potential for confusion and even though the scale is more realistic introducing this change 3 years into the iPhone OS could cause more fuss than it solves.

I think this is part of the reason Apple decided to make a visual change to the display of the bars (1-3 are taller) so that at a glance someone who knew (Apple Genius, forum poster etc) can tell whether the phone is pre-or post 4.0.1, and explain the discrepancy.

Can't wait to see what they announce tonight, the pessimist in me thinks they'll just try to sweep the whole thing under the rug, but we'll see.

[Ben]

At least we'll now know that when we've got signal on our iPhones it's usable. The number of phones I've had (here's looking at you, Sony Ericsson) where I'd supposedly have great signal, only to try and do something and have it all vanish or the connection drop, well, there have been a fair few.

I'm still on 4.0 at the moment - rather looking forward to the update, need to get hold of my Mac mini so I can sync!