Here in the U.S., "broadcaster" would probably be the best option of those three.
But, you may still get lots of questions about what you do. Broadcaster isn't very specific. I tend to associate the word with the news, but that's because I don't work in t.v. or radio and so don't know the lingo. "Locuter" isn't used.
I associate "announcer" with someone who only announces short segments. You could probably say "t.v. and radio announcer" for your voice-over work, although where I live people usually call themselves "voice-over artists." "Voice-over artist" may be a good option, but it doesn't include your podcast. I would say that if you're not filling out a form with a one-word answer, you can introduce yourself saying, "I work in tv and radio doing voice-overs and I also have a podcast." Admittedly that's not very succinct, but it's probably the clearest.