What are prerequisites for a radio announcer's voice?

just in the last two years, i’ve evolved from listening to music on the radio to newstalk radio. almost all of the announcers have really distinct voices. one particular female voice is almost “marge simpson” like and sounds like she’s smiling through the whole traffic report. i LOVE her voice, but she can’t be smiling the WHOLE time, right?

what does it take for your voice to have personality, but we never see the faces? are children wjo speak loudly and clearly radio-bound? what does it take? why are people with distinct voices in radio?

which came first? the love of radio or the voice?