Elimination of Harmonics in Vacuum Tube Transmitters

A brief description is first given on the present state of technique concerning the suppression of harmonics radiated from vacuum tube transmitters. A simple method of eliminating the strongest one of the harmonics is then suggested, in which a parallel resonant circuit having its resonant frequency slightly lower than that of the harmonic to be eliminated is connected to the plate circuit and coupled to the main oscillatory circuit. The method has been found effective experimentally as well as theoretically.