Radios are features in-game which play music in the background. They can normally be destroyed by shooting at them or by blowing them up with grenades or launchers. Some radios are intended to act as a spawnpoint, instead of a flag being used as a spawnpoint.
Most radios in the mod play music, such as the song Tu Es Partout by Édith Piaf. However, some radios don't play music. Some of them, like on the Japanese vs USA map Operation Coronet, they are spawnpoints for the Japanese forces. Disable them like any other radio by shooting at them. Normally, they don't spawn back.