History of Science and Engineering Annotation << Back HISTORY OF EXPERIMENTAL OBSERVATION OF HIGH FREQUENCY ALTERNATING CURRENTS A.F. Smyk The article presents the history of the development of experimental detection and transmission of electromagnetic waves using high–frequency alternating currents in the second half of the XIX – early XX century. During this period of development, experimental studies of scientists from different countries were of great importance: J. Henry, G. Helmholtz, F. Brown, G. Hertz, N. Tesla, P.N. Lebedev and A.S. Popov, considered in the article. A chronological table of the most significant discoveries in the history of the experimental study of microwave radiation has been compiled from the moment of the first observations of an electric discharge to the invention of radio. The modern development of quasi-optics is associated with the use of the microwave range of electromagnetic waves to transmit energy over considerable distances, the ideas of which were expressed in the works of the discoverers. Keywords: electromagnetic waves, electric discharge, microwave radiation, Leiden jar, Rumkorff coil, Hertz experiments, Nikola Tesla, Popov radio receiver, wireless transmission of electricity. DOI: 10.25791/intstg.7.2022.1364 Pp. 03-21.