Apple had released iOS 4.1 for iPhone yesterday. It includes fix for the proximity sensor, Bluetooth and iPhone 3G performance problems and some major features such as HDR photos, HD video upload, ability to buy TV show rentals and Game Center, Apple’s social gaming network.
The Field Test mode shows the antenna signal strength or more accurately signal to noise ratio in dBm rather than as bars.
To enter the Field Test mode, all you need to do is dial:
The signal bars will now display the signal in a dB reading as seen below.
To exit “Field Test” mode, hit the Home button.
Signal strength ranges from roughly -50 to -105 , closer to zero means a better signal, i.e. – 50 (roughly full signal) is better than -105 (roughly no signal).
So if you plan to try it out, please let us know your results in the comment section below.