Turning off 3G on EVO

I live in DC and it has fantastic 4G coverage. Is it possible to turn off 3G and keep 4G on? I'm concerned that keeping both on would waste the battery.

Second question, can you have your Voice off and your 4G on? I go for jogs and listen to Pandora and hate when a call comes in while i'm jogging.

Thanks for your help!

Unclick mobile network under Wireless & Networks to disable 3G. I would assume 4G will still work if you have it checked on. The only way I have found to not get calls or texts is to go into airplane mode since I still get both when mobile network is off.