Hi kapuhy,
I think radio Antenna values are fully functional and yes, I agree with you that - so far - they have been largely overlooked by modders. Unfortunately directional antennas can't be simulated, so for instance we can't get Radio London to broadcast their propaganda programs in German over Germany, in Italian over Italy, etc.
Other than that, there are other cool things that can be made with radio stations. There used to be some interesting threads on the topic posted in the SHIV-modding subsorum. When I find them I will drop their link here