The old-fashioned, v-shaped antenna on top of your parents' TV can be called rabbit ears.
Once upon a time, television viewers had to regularly adjust the rabbit ears on their TV sets to get a clear signal and a static-free image on the screen. If you don't have cable or a satellite dish, but you want to watch network TV shows, you might use rabbit ears instead — although in many areas, they can't pick up distant radio signals. Rabbit ears get their name from the V shape of their long, adjustable rods.