The Obsessive Hunters Chasing Weather Balloons All Over Europe

Some retirees take up fly fishing. Others pick up golf. But when Roland—or “F5ZV,” as he’s known on ham radio—left his job in Belfort, France a decade ago, he devoted his newfound leisure to a far more peculiar hobby: hunting radiosondes. The white plastic boxes contain instruments to measure things like wind, temperature and humidity; …