On my EVO, my time without a signal is usually over 90%. I live in a good coverage area, but low bars inside of my house/office (both the same, where I am all day) I put on airplane mode for kicks, and in 12hrs, the battery dropped only 10%. So that being said, it seems to me as if there is a definite conclusion between signal strength and battery life. Any suggestions? and yes, I did the GSM-DCMA trick .