 Given that much of the world's communications have moved to optical fiber cables, which are difficult but not impossible to intercept.Much ECHELON specification is based on clues, such as noting the geographic location of various large satellite receiving antennas, then plotting the vertical and horizontal coordinates of the parabolic "dish" of the antenna.These can be correlated with the known positions of communications satellites to project that the antenna is intended to receive the signals of a particular satellite.