Part of the linked page describing the WWVB transmission station which I enjoyed: "A computer is used to automatically tune the antennas during icy and/or wind

Part of the linked page describing the WWVB transmission station which I enjoyed: "A computer is used to automatically tune the antennas during icy and/or windy conditions. This automatic tuning provides a dynamic match between the transmitter and the antenna system. The computer looks for a phase difference between voltage and current at the transmitter. If one is detected, an error signal is sent to a 3-phase motor in the helix house that rotates the rotor inside the variometer. This retunes the antenna and restores the match between the antenna and transmitter." Cool technology :)