Electrical Review, May 31, 1919, pages 895-896:

Speeches  Through  Radiotelephone  Inspire  New  York  Crowds
Spectacular  Demonstration  of  Radiotelephony  During  the  Victory  Loan  Drive--Speeches  Delivered  from  Airplanes--Features  of  Equipment  Used
DURING the three weeks covering the recent Victory Liberty Loan drive the crowds that daily thronged "Liberty Way" in New York City were accorded the unusual sensation of having spoken messages come to them out of the air. Victory Way
    The medium that accomplished this modern miracle was the radio telephone that played a considerable part in the war. It will be recalled that back in 1915 the engineers of the American Telephone & Telegraph Co. and the Western Electric Co., in co-operation with the Navy Department, gave a remarkable demonstration and Secretary Daniels at Washington, D. C., talked to all the naval stations in the country and with the commander of a war ship far out at sea. Later one-way communication was established between the station at Arlington, Va., and Paris, France, and the Hawaiian Islands.
    When the war closed the United States had a highly efficient system of radiotelephony, based on these early developments, by which constant communication could be maintained between ground stations and flying airplanes and between airplanes in motion.
    Having done its bit in winning the war, the radiotelephone was given the task of inspiring the Victory Way crowds to put their dollars into bonds to help pay for victory. It performed its task with great success. control room
    On Victory Way the wireless antennas were stretched over the concourse : 112 loud-speaking telephone receivers were suspended from these antennas in four rows. In front of the speaker's desk there were three microphone transmitters on iron uprights. This was all the visible evidence of the equipment. But in the nearby Railroad Y. M. C. A. Building there was a maze of wires and switches forming the wireless sending and receiving apparatus. From this point the wireless messages passed over the wires to the control room behind the speaker's desk on the east side of the enclosure and were there amplified many million times so that they might be heard by the crowds on the concourse through the medium of the loud-speaking receivers. speaker's stand
    Three high-grade long-distance circuits of the American Telephone & Telegraph Co., each approximately 227 miles long, were wired direct between the office of Frank R. Wilson, director of publicity for the Victory Loan campaign, at the Treasury Building, in Washington, and the control room on Victory Way. Many noted speakers talked direct from Washington to the great audiences on Victory Way from Mr. Wilson's office. A return circuit made it possible for the speakers at Washington to hear other speeches, music and applause from the audience in New York. Among those who talked to the crowds on Victory Way were: Mrs. Carter Glass, wife of the Secretary of the Treasury; Miss Clara D. Noyes, chairman of the Bureau of Nursing Service of the Red Cross; Mrs. Newton D. Baker, wife of the Secretary of War; Mrs. Larz Anderson; Franklin D. Roosevelt, Assistant Secretary of the Navy; Major General George Barnett, and Count de Chambrun, of the French Embassy at Washington. control room
    Roughly, the operation of the radiotelephone was as follows: Radio waves received on the antennas passed to the tuning apparatus in the receiving set, by means of which the desired wave lengths are selected and converted into currents of audible frequencies by the detector tube, after which they are amplified about 1500 times and conducted to the telephone control room, where an additional amplification of from one to five million times is provided. The energy is then delivered to the loud-speaking receivers.
    The transmitting apparatus consists of a high-frequency oscillator and means for modulating the high-frequency currents in accordance with speech sound waves, which were impressed upon the diaphragm of the telephone transmitter by the speaker's voice influences.
    The source of electrical energy for operating the radiotelephone equipment was a set of automobile storage batteries used to deliver current to heat the filaments of the vacuum tubes and run the dynamotor delivering energy to the plate circuits of the transmitting tubes. There was also a panel for controlling and distributing the power to the transmitting and receiving sets. Special equipment had to be furnished to magnetically shield the control room in order to eliminate the possibility of disturbances from outside electrical loud-speaking telephone
    Besides the speakers at Washington, many notables addressed the audiences from the speaker's stand. Among them were: Mrs. Vincent Astor, Mrs. W. G. McAdoo, Miss Ann Morgan, Admiral Mayo, Rear-Admiral Plunkett, Rear-Admiral Rodman, Brigadier-General Cole; Lieutenant-Colonel Hughes and Martin Vogel. Without the loud-speaking telephone receivers it would not have been possible for a large part of the Victory Way audiences to hear these speakers.
    More miraculous, however, were the radiotelephone communications both from the Western Electric Co.'s station on West street and from a navy seaplane flying over New York.
    From the land sending station, a five-minute speech was transmitted across the city by wireless telephone, received at the antenna over Victory Way, multiplied and transmitted to the loud-speaking receivers, and every word was clearly heard by a crowd of 10,000 people. Music was also transmitted by wireless telephone very effectively.
    The demonstration of the speech from a flying plane about a thousand feet above the street seemed the more difficult because the whirring of the propellers would seem to drive out any other sound. In spite of this handicap, which made the hearing of nearby voices difficult, the observer in the seaplane addressed the crowd through his wireless equipment, the radio message being received by the antennas over the concourse and transmitted to the crowd through the loud-speaking receivers. Not only could the crowd understand the flier's appeal to "Buy Bonds," but anyone who knew him could even recognize his voice, and when he announced that he would drop a shower of circulars, the crowd waited expectantly until the promised shower appeared.
    The flier did not leave for his headquarters until the officials had assured him by wireless telephone that his message had been received and understood by the assembled multitude.