In-game VON system is very done in magical way, they have nearly no noise or static sounds, nearby environment sounds.
I think they are cool to have for semi-realistic vanilla gameplay:
- Coef for static noise (bzzt... bzzt...)
- Beep sound when a transmit has started and ended
- Toggle nearby sounds (like if the player is in a helicopter, the rotor/engine noise will be transmitted to others. Same for gunshots or such)
- Changeable transmission quality
- Blocking radio by distance/terrain/buildings/weather (probably too much for a *simple* radio system)