When this is done we have a syntonic system which is not easily affected by electric waves of other than the right period or approximating thereto.
Attendance at a lecture on Hertzian waves given by Sir Oliver Lodge at the Royal Institution in 1894 resulted in the Lodge-Muirhead syntonic system (see 26.538), which anticipated Marconi.
Marconi in an operative system of syntonic wireless telegraphy.
Lodge was, however, fully aware that it was necessary for syntonic telegraphy to provide a radiator capable of emitting sustained trains of waves.
When this is the case, if discharges are made across the spark gap oscillations are excited in the closed circuit, and these induce other syntonic oscillations in the antenna circuit.
When oscillations are created in the closed circuit syntonic oscillations are created in the antenna and electric waves radiated from it (fig.
Slaby in Berlin shortly afterwards made a similar exhibition of syntonic electric wave telegraphy' O.
At a later date a syntonic system comprising, as above stated, an antenna directly coupled to a resonant closed circuit was put into operation by Lodge and Muirhead, and much the same methods have been followed in the system known as the Telefunken system employed in Germany.
The problem of syntonic electric wave telegraphy is then to construct a transmitter and a receiver of such kind that the receiver will be affected by the waves emitted by the corresponding or syntonic transmitter, but not by waves of any other wavelength or by irregular electric impulses due to atmospheric electricity.
A vertical transmitting antenna sends out its waves equally in all directions, and these can be equally detected by a suitable syntonic or other receiver at all points on the circumference of a circle described round the transmitter.