Test your iPhone 4's Antenna Reception in iOS 4.1 with Field Test Mode (Updated)

What a big one! Gizmodo could find a way to check your iPhone 4's antenna reception issue which was discovered by iPhone 4 users when they hold the device from the bottom left. The method to test your antenna reception only works on the newly released iOS 4.1, check it below.

First, you will have to upgrade your iPhone 4 (or any iPhone) to iOS 4.1 (Remember: It kills your jailbreak and unlock). Then, Dial *3001#12345#* into your phone. Now, the signal bars will be replaced with a number (i.e. -89) as shown in the screenshot above. The higher the number it is, the worse the signal it is.

Update 1: For a better understanding of  numbers resulted from the test , we offer this picture which simply show you the quality of your result.

In short :
-From -121 to -107 dB reception is weak and corresponds to a notch
-From -107 to -98 dB are the two notches
-From -98 to -87 dB are already in a good phase with 3 notches
-From -87 to -76 dB have great reception
-From -76 dB we get a good reception 
[via Gizmodo]

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