after my i dont touch my iphone for 1-2-3 hours i clilck the home button and slide to unlock the keyboard i can see that there is no signal next to the carrier logo.

its not happaning all the time but when it to i dont know that my phone is off and i cant get calls, after a 3-5 seconds after i unlock the keyboard its reconnect.

any suggestion?

(1.1.4 uses iliberty for hack it)