The newly-reactivated
High Frequency Active Auroral Research Program (HAARP) facility in Alaska was back on the
air in February under the auspices of the University of Alaska-Fairbanks. There
were two types of experiments, according to the ARRL Letter. One was called "airglow" and was an effort to create an artificial aurora. The second was a transmission of a series of tones to test the so-called Luxembourg effect," in which tones transmitted on two different frequencies mix in the ionosphere to reflect back a combination of the tones on a single frequency.
Reception reports were requested. Stay tuned for more tests in the future.