Brandon Lewis asked:
I understand that light and radio are very much the same kind of thing. Yet the equipment we use to generate visible is very different from that which we use to generate radio. Why is that? Could you generate visible light from apparatus similar to that used to transmit radio? I.e. could you build a transmitter and "tune" it emit a visible frequency? If so, what would it look like (I am imagining some sort of glowing antenna)? If not, why not?