In Apple’s eyes the media took the iPhone 4 antenna nonissue way too far and, if you recall, issued a press conference to calm the masses and try to get a grip on the misinformation floating around. Whether you agree with them or not, there’s now a sure fire way to test your own iPhone’s cell reception using a hidden feature added into iOS 4.1.
Cell reception is measured in decibels and the famous Consumer Reports piece reaffirmed what many iPhone 4 users were seeing; a significant drop in the decibel readings when the lower left gap was bridged. The average consumer only has those vague bar that Apple calibrated with an iOS update shortly after their press conference. Now, bundled into iOS 4.1 comes a Field Test mode that allows you to get an accurate dB reading on your signal. It won’t change your reception but it’ll give you a number so you can more accurately pinpoint where you fall on the reception spectrum.
To activate Field Test mode, open your dialer and call *3001#12345#*. You’re bars will disappear, replaced with a decibel reading ranging anywhere from about -51 dB to a spotty -113 dB. Once you hit the home button, your bars will return. If you hit the sleep/wake button while in field test mode, your dB reading will remain. It’s only after you hit the home button to exit the Field Test mode that your bars will return. Apparently Field Test mode hasn’t been updated to support Apple’s multitasking…
I’ve manage to get a reading beyond -113 but rest assured no call will go through. On my 3GS sitting at home with no death grip, I’m floating between -90 and -100. Sadly I’m on the fringe of a 3G tower. How does yours compare? Give it a shot and let us know how you fare.