Daily Archives: January 10, 2016

Seventy Years Ago Today …

… we entered the communication space age with the successful completion of Project Diana, an experimental project of the US Army Signal Corps in 1946 to bounce radar signals off of the Moon and receive the reflected signals. The first experiment in radar astronomy, it used a large transmitter, receiver, and antenna array constructed for the purpose in a laboratory at Camp Evans. The transmitter, provided 3 kw at 111.5 MHz in 1/4 second pulses applied to the antenna, a reflective array attend composed of an 8×8 array of half wave dipoles in front of a reflector that provided 24 dB of gain. Reflected signals were received about 2.5 seconds later (which is the time required for the radio waves to make the 768K km / 477 mi journey), proving the technique and successfully completing the experiment.

While moonbounce communication was not that practical (outside of its use in radar astronomy to map Venus and other nearby planets), as it was abandoned by the military with the advent of communications satellites a mere two decades later, and is now only used by amateur radio operators, it did usher in the communication space age and should not be forgotten.