HAARP Moon Echo Experiment

Tonight, the HAARP transmitter in Alaska was used to direct exceedingly powerful radio pulses (around 4 Gigawatts effective radiated power) at the moon at a frequency of 6.7925 MHz and I could easily receive the echoes from the two second bursts here on earth with my amateur radio rig.

Waterfall spectrogram of radio echoes from the moon.
Click on the photo, then on "all sizes" for a larger image.