Being the experimenting kind I took screenshots of my iPhone 4 status bar before and after updating the software/firmware to 4.0.1.
In the Unofficial Apple Testing Labs (which double as my house) I have my summer office in a “back room”. This is at the back of my house due to lesser temperatures. So I was able to test a high db as well as a low db scenario. Note that this is regular GSM/EDGE connections, I don’t get 3G where I live.
The “Death Grip” was performed by cupping the left hand around the bottom of the phone making sure to touch the black strip with the base of my thumb.
You can actually feel how much stronger the reception is with fewer bars. See how much larger they are?
Now let’s refer to the great chart that Anandtech updated to show the db-to-bars mapping on 4.0 and the update. AnandTech reader Mike Escoffery, Director of Design and User Experience at Media Platforms, created his own diagram to help compare the old and new way of iOS signal strength reporting:
So based on this extremely useful chart, how is my iPhone 4 performing?
Well, in the front of the house it was showing 5 to 5 bars before, suggesting a range between -91 and -51 db. After the update it’s 3-4 bars. The maximum result of a “grip of death” for me calculates to be 22 db (98 – 76). So in the original mapping this drop stayed within the range from -91 to -51, so it must have been at least -71 db.
On the front porch, after the update, I was starting out with 5 bars, but it settled on 4, so I took this for my calc, but it appears to be right on the verge there, -71 or -76, not much of a difference. But -76 minus 20 db is sufficient drop to get into the 3 bar area.
Now for the “bad reception area” that is my office, aka “back room”. I appear to be getting better than -104 db. A minus 20 db drop puts it to one bar or in the case of the above comparison to “No Signal”. So no change there in user experience, only the larger bars.
The conclusion to draw is that making the mapping more linear causes the reported reception to be way more useful and honest, brutally so. Since the iOS 4.0.1 now maps down to -121 db you theoretically get 8 db extra room before losing the connection. Having a finer mapping has a disadvantage though: now everybody is able to show a signal drop, even with 5 bars. So I guess I’ll never let anybody touch my i4 without a case because I don’t want to be ridiculed or trying to explain the above to stupid non-Apple-laymen.