The electromagnetic wave concept. Maxwell’s theory predicted that the index of refraction of a transparent medium is equal to the square root of the dielectric constant (a measure of specific inductive capacity) of the medium. This relation was not consistently observed because the dialectic constant was not measured at optical frequencies, and the apparent discrepancy added doubts to the validity of this theory. Maxwell did not include any accounts of the origin of radio waves, and although effects of osculatory electrical discharges had been observed much earlier by Joseph Henry and others, the theory was not confirmed until after his death, with the experiments (1887-86) of Hertz. Hertz produced electromagnetic waves, demonstrated their reflection, refraction, and interference in complete accord with Maxwell's results, and also took steps toward a theory of radiation, relating waves to their source. The concept of retarded potencies had been introduced earlier in 1867; by a physicist, Ludvig Valentin Lorenz of Denmark, but their relation to the waves predicted by Maxwell was not at first clear. Other predictions of Maxwell’s theory, including the pressure of light, were verified inthe years that followed.

Hertz/He:tz//hertz/n/hertz
[Wne] (a measure meaning) one time each second

THESE RADIOWAVES ARE COMING AT 1500 CYCLES PER SECOND.
THAT'S 15 KILOHERTZ OR 1500 HERTZ

hertz, unit of frequency equal to one cycle per second, named in honour of the 19th century German physicist Heinrich Hertz. The abbreviation is Hz. The frequency of radiowaves is commonly measured in kilohertz (thousands of hertz, abbreviated kHz)

Hertz (tsorhàr). Heinrich Rudolph (1857-94).
German physicist.
Hertzian adj. waves, electromagnetic waves, first demonstrated by Hertz in 1888, and subsequently utilized for wireless telegraphy.

Hertz, Heinrich Rudolph (b. Feb 22, 1857 Hamburg - d. Jan 1, 1894, Bonn), physicist who was the first to broadcast and receive radio waves. He received his Ph.D. magna cum laude from the University of Berlin in 1880, where he studied under the noted physicist Hermann von Helmholtz. In 1883 he began his studies of the electromagnetic theory of James Clerk Maxwell of England. Between 1885 and 1889, while he was professor of physics at the Karlsruhe Polytechnic, he was able to produce electromagnetic waves in the laboratory, send them through space, and measure their length and velocity. He showed that the nature of their vibration and their susceptibility to reflection and refraction (bending) was the same as that of light and heat waves. As a result, he established beyond any doubt that light and heat are electromagnetic waves.
In 1889 Hertz was appointed professor of physics at the University of Bonn, where he continued his researches on the discharge of electricity in rarefied gases. His scientific papers were translated into English and published in three volumes:

ELECTRIC WAVES (1893)
MISCELLANEOUS PAPERS (1896)
PRINCIPLES OF MECHANICS (1899)