Popular Science, July, 1924, page 65:

Setting  the  Pace  in  Radio

By  Jack  Binns
RE-BROADCASTING undoubtedly is the year's most important development in radio. Re-broadcasting is exactly what its name implies--a second broadcasting by several stations of radio programs transmitted to them from the stations at which the programs take place, thus multiplying greatly the distance through which the programs travel and increasing the number of potential listeners.
    Of course, in the case of presidential addresses and other important events, this has been done many times by means of land telephone lines. But through the recent development of an extraordinary short-wave transmission system, the entire process now can be accomplished by radio, and the frequently discussed possibility of one man's addressing the entire world probably soon will be realized.

THE principle upon which radio re-broadcasting depends is quite simple, although the technical difficulties surmounted in its development were tremendous. In re-broadcasting, a program is transmitted on two wave lengths. One is in the broadcasting range of from 250 to 600 meters. These signals can be picked up by ordinary receivers range. The other is 100 meters or less, which is below the receiving range of ordinary receivers.
    The re-broadcasting stations, however, are equipped with receivers capable of picking up the short-wave signals, and, when they are received, they are re-broadcast automatically over a wavelength within the broadcasting range.
    Re-broadcasting is new, but it is no sudden development. It is the result of years of painstaking work by engineers of the Westinghouse Company under the direction of Frank Conrad.
    Thus far most of the work of the experimenters has been done with a non-directional aerial at station KDKA, Pittsburgh. Now a novel type of aerial is being developed for still greater efficiency in radiating the short waves toward KFKX at Hastings, Neb., the re-broadcasting station, and across the Atlantic to England. Recently the short-wave relay was used in broadcasting a program from station WJZ in New York City. A telephone wire carried the program to station WGY, Schenectady, whence short-wave transmission carried the signals successively to KDKA, to KFHX at Hastings, Nebr., and to KGO at Oakland, Calif., thus covering virtually the whole country.
    The important thing is that the preliminary work has been completed, and the possibilities defined. It will not be long before one broadcasting station can be linked up with all others. Then any speaker can "tell the world" in reality.