[GuyWithNoLife]

It takes more battery power for your phone to establish EVDO service when you're in an area with poor signal (switching from 1x to EVDO) than if your phone had good EVDO reception. In some areas EVDO isn't on every tower, so you may get 1 bar of EVDO service but then 4 bars of 1X service (I notice this in some places out of town I go for work). I have noticed significant battery drain in situations like this.