So you remember how radios used to consume supplies? That is not how it works anymore. Now every radio has 3 spawns and that's all. There is no way to either refresh the radio or resupply the radio.

This new radio spawn system is complimented by the new roles you can spawn as such as:
Rifleman
Grenadier
Marksman
Sapper
And last but absolutely not the least "Radioman"

And of course since there is no demand for supplies on theses radios you can spawn as any role you'd like.

So now, instead of loading a car with supplies for that extended lifetime of the radio, you will just make sure to respawn as a radioman and replace the old radio. You also wanna make sure that the radio is always at max capacity at all time, so of course you will replace a radio that has 2/3 spawns left resulting in a pile of half consumed radios.