Detection Probability of Terrestrial Radio Signals by a Hostile   Super-civilization
  Comparison of the total number of the radar astronomy transmissions with respect to that used for sending messages to extra-terrestrial civilizations reveals that the probability of detection of the radio signals to extraterrestrials (ETs) is one million times smaller than that of the radar signals used to study planets and asteroids in the Solar System. 
Alexander L. Zaitsev