On the Electrical Operation and Mechanical Design of an Impulse Excitation Multi-Spark-Group Radio Transmitter

After a discussion of impulse excitation, three forms of gaps suitable for such extreme quenching are described. Braun tube oscillograms showing the operation of such gaps for various values of "inverse charge frequency" (number of secondary oscillations per primary discharge) are given. They show a remarkably regular gap-functioning over hundreds of thousands of cycles. The problems of commercial construction of such sets are then considered. The necessity for using an alternator giving a special (highly non-sinusoidal) wave for feeding the gap transformer is demonstrated. The use of a modified tone or "concentration circuit" across the gap is justified on the basis of the increased receiving station audibility per ampere in the transmitting antenna. The actual 0.5- and 2-kilowatt sets are then fully described, and the simple mode of wave changing explained. The receiver is also considered. A standardized antenna for these sets is shown.