I too hate that annoying beeping. Feels like the roadrunner is running arorund my boat.
If you want to get rid of it, you can go to your data/sound folder, and in each speech folder replace files:
RaM_K_New_message_received.ogg
RaM_P_New_message_received.ogg
RaM_S_New_message_received.ogg
with the vanilla ones wich just have the radio operator saying you got a new message.
I made a small mod that does this. you can find it here:
http://www.mediafire.com/file/jk61li..._radio_msg.zip
Just unzip, copy to your mods folder, and activate with JSGME