Unveiling the Ionosphere

The presence of a conducting layer in the upper atmosphere that made long-distance radio communication possible was hypothesized in 1902. But experimental proof of the existence of the "Kennelly-Heaviside layer" (now called the ionosphere) was not forthcoming for more than two decades. Beginning in the summer of 1925, DTM researchers Gregory Breit and Merle Tuve developed a method of bouncing pulsed radio signals off the ionized layer and observing the echoes. Through cooperative experiments with the Naval Research Laboratory, ionosphere heights of 50 to 100 miles were demonstrated. Their technique paved the way for the worldwide study of radio transmission and laid the groundwork for the later development of radar.