Mostly while we are on the wasteland we have two weapons in hands (close combat/long range, fast shooting/slow shooting etc.) so we can't have radio on.
Why we can't hear comunicates while radio is in invetory? For example we can hear "'sh..whe..shh..r you..shh' instead of 'shh..where are you..shh' because of the backpack - but we can still hear sth, that someone is talking on the radio, then we can take radio in hand and respond
We will hear only radio that was in hand last time (so while we have 4 radios with different channels we can still hear only one)
According to the fallout system, items in your backpack aren't all in your backpack. You wouldn't stuff a sword or sledgehammer in a backpack, you'd strap it to your back and side. Ammo may not be in a backpack, it could be on a belt. The fallout system treats the two hand idea as "This is what I'm gonna use, lets keep it real close". So two guns, one in each hand, could represent a gun in the players good hand and the other in a holster, gun in each hand, or both guns holstered. To further expand this thought, guns and caps, I'll have my gun holstered and my caps "tucked away" in hands reach (Kinda helps explain why hand items can't be stolen)
So I don't see how communications have to suffer if the radio is not in hand, because you don't need to toss it in your backpack. You can clip a radio to your belt and be able to hear things just fine and reach you hand over to tap the button and speak.
I like the idea of freeing that slot up from radios. Maybe take it to the next level, add a "Belt" slot to the inventory screen. So you can clip a radio to it, or hide your caps or ammo from thieves, and so on.
Radios used in combat should use 2aps per msg, including distress calls.
The fallout system, like dungeons and dragons, considers talking to be a "free action" be it in combat or not.
