In a generator for feeding an ELF transmitting antenna with a short-duration transmitting signal, a multiplicity of series-connected NiCd accumulators is provided as power source. The series circuit exhibits a plurality of taps which can be connected to the antenna terminals via controllable semiconductor switches. The switches are operated by a control device as determined by the desired transmitting signal in such a manner that the transmitting signal is approximated by a staircase-like step variation. Simple filter means can be used for suppressing unwanted higher-frequency signal components and thus for smoothing the stepped variation.
