Lunar Reflections of Terrestrial Radio Leakage

Terrestrial radio leakage as reflected off the moon has been observed with the Arecibo antenna. We find that military radars and television transmitters are main contributors in the 150–500 MHz range, as predicted in the model of Sullivan et al. (1978). The earth indeed is revealing itself (eventually) to any interstellar eavesdropper with an Arecibo-like antenna at distances up to 30 light years, and with a Cyclops-like system up to fifteen times farther.