Institute for Telecommunication Sciences / May 1937
In May 1937, the National Bureau of Standards began publishing monthly reports on the state of the ionosphere as a service for radio broadcasters. The ionosphere, a highly ionized and layered portion of the upper atmosphere, is important to radio communications because it scatters radio signals and reflects them back to earth, allowing broadcasters to increase their effective transmission area. NBS researchers had only recently amassed enough data to understand the ionosphere's effect on radio fading and interference. The new reporting service included information on the height and characteristics of the ionosphere and disruptions by weather and solar phenomena. Predictions of conditions for the next three months were based on atmospheric and solar cycles were assisted by an automated radio transmitter in Meadows, Maryland, that recorded radio waves reflected off the ionic layers to map and characterize them. This data was used by other governmental agencies to adjust broadcasting frequency, power, and direction to ensure radio signals reached their intended destinations. In 1939 the reports were released to commercial broadcasters as well. Nearly 80 years later, ITS continues to support other governmental agencies and commercial enterprises by publicly releasing the results of cutting edge radio propagation research through regular reports and technical bulletins.