In a heat exchanger for cooling air, tubes are disposed vertically and header tanks are connected to the ends of the tubes. The switching elements are arranged with the antenna elements and transmission feed lines to, when selectively closed, electrically couple selected antenna elements and transmission feed lines to one another to generate an antenna configuration selected from a plurality of antenna configurations. The plunger comprises an outer surface, a top end, and a lower end that mates with the nozzle tip inner surface. For embodiments using LDPC ECC code, uncertainty can be added for the bits of a suspected cluster location.