Forget her measurement of your iPhone's signal strength using only dots or lines. The following simple hack allows you to see the real strength of your mobile signal.
If you want your mobile signal measurement to be more accurate than the little dots on the top left of your iPhone screen, then you should try the following hidden feature of the built-in operation Field Test.
To access the Field Test Mode, you will need to prepare:
Turn off Wi-Fi (Settings> Wi-Fi)
Turn off LTE, (Settings> Cellular> Turn on LTE)
Then go from your phone application type the following:
* 3001 #12345 # *
Then dial the "number" and you will activate the Field Test function.
To exit, simply press the Home button.
If you want to replace the signal strength dots with decibel, press and hold the power button until the Slide to power off icon appears. Next, release the power button and then press and hold the Home button for about five to ten seconds until the Field Test Mode screen turns off.
If the result you have is about -50 decibels, it is very good, while a weak signal will be about -115 denim. Basically as close to zero as the number, the better your mark.
If you want to restore the dice now, simply restart your iPhone with hard reset (Home and Power pressed together).
For Android users, you can see the signal meter (but you can't have it permanently on your screen). Just go to Settings> About phone and it's there, along with the network type.
