Dipole antenna other monopole) antennas on the basis of dipole antennas of which they are one half. German physicist Heinrich Hertz first demonstrated the existence of radio waves in 1887 using what we now know as a dipole antenna (with capacitative end-loading). On the other hand, Guglielmo Marconi empirically found that he could just ground the transmitter (or one side of a transmission line, if used) dispensing with one half of the antenna, thus realizing the "vertical" or monopole antenna. For the low frequencies Marconi employed to achieve long-distance communications, this form was more practical; when radio moved to higher frequencies (especially
Guglielmo Marconi day during which the entire transatlantic path was in daylight. It is now known (although Marconi did not know then) that this was the worst possible choice. At this medium wavelength, long-distance transmission in the daytime is not possible because of heavy absorption of the skywave in the ionosphere. It was not a blind test; Marconi knew in advance to listen for a repetitive signal of three clicks, signifying the Morse code letter "S". The clicks were reported to have been heard faintly and sporadically. There was no independent confirmation of the reported reception, and the transmissions were difficult to