As far as “what’s it for?”: All antennas are designed to receive and/or transmit on some range of frequencies. In this case, the antenna is designed to operate on the frequencies the FCC has assigned to the amateur radio service.
Don’t be fooled. It’s obviously a shield to protect us from the Jewish Space Lasers that Margorie Taylor Greene (aka Marge Three Toes) warned us about. She also warned us about Pelozi having a “Gazpacho Police” and, of course, about Bill Gates wanting us to eat fake meat “grown in a peach tree dish.”