Not sure if you're playing through them right now, but I am so I'll just write down the ones that I find.
Level 3 - As soon as the level begins, and right after you finidh spraying down the area with the turret, you will head in to an area with a group of 3 people in it. After you kill them and turn to the right, the radio will be on the left next to some boxes.
Level 4 - Right after turning your Night Vision on for the first time, you will turn right and face a group of enemies inside a courtyard. The radio is right in front of you on the ground.
I'll edit them in as I move through the missions.
Last edited by Rep; 01-24-2013 at 03:51 PM.