I think your suggestion is great. The radio manager is one of the only jobs that requires external clientside software / hardware to work properly. Using an ingame prop / entity would open up the radio manager job to more people. Specifically people that don't know how to setup their pc's to transmit audio over mic. It would also improve the overall sound quality of the music, since music over mic is quite bad at transmitting music. Additionally you could implement some sort of filter to block music that is against the rules / tos (maybe a blacklist, moderated by staff?). This should definately be implemented in some form!