Radio Proximity Awareness
Simple suggestion, for reference I believe Insurgency Sandstrorm does this.
When you key up on the radio, and the person is near you, they will also transmit in local.
This could be achieved by simply broadcasting at a smaller radious to local, at a lower volume. (50%)
This would allow people to have "orientation" of communications over the radio, and improve immersion. If my buddy next to me is speaking into their radio, I should be able to hear them. (In most circumstances, if he is speaking at normal volume.)
Would be very cool, to hear a SL talk over command coms, but not hear the response back from the command radio line.