In order for the fight broadcast to be a success, a large number of amateur radio operators had to be recruited, in order to operate the receivers. As noted in this request for volunteers: "In participating in this great event, unparalleled in the annals of sport or the history of radio communication, the amateur will be identified with an undertaking which has for its object the rehabilitation of the devastated regions of France, and to provide for the comfort and happiness of the men of our navy when off duty--objects which most certainly should appeal to the patriotism of every amateur."
 
The Wireless Age, July, 1921, page 10:

July  2nd  Fight  Described  by  Radiophone

The  Great  International  Sporting  Event  Will  Be  Voice-Broadcasted  from  the  Ringside  By  Radiophone  Under  the  Direction  of  the  National  Amateur  Wireless  Association  on  the  Largest  Scale  Ever  Attempted

    BROADCASTING by wireless a voice description of the Dempsey-Carpentier championship contest is not only a novelty for the annals of sport, but a new development in the field of applied science. The arrangements already made for the radiophone transmission on July 2nd for new and unusual departures in communication engineering. Never before has anyone undertaken the colossal task of simultaneously making available a voice description of each incident in a fight to hundreds of thousands of people. Transmission of the voice by wireless on a large scale is new to the world, and the event has no little historical significance. The plans for its introduction have been carefully made so as to insure a complete success. Due to the fact that French and American causes are to be aided through the exhibitions in various cities, it has been possible to secure apparatus and services that would otherwise be available only at prohibitive cost.
    The transmitter to be used in this unusual voice broadcasting is the most powerful wireless telephone set of commercial type ever built. It is being donated by the Radio Corporation of America for the purpose. The set has been assembled at the Schenectady laboratories of the General Electric Company, and when completed, will be brought down the Hudson River to the Lackawanna Terminal at Hoboken, N. J., where it will be installed. The 400-foot tower at the Lackawanna Terminal will be used. An antenna of six wires, on 30-foot spreaders, will be swung between the 400-foot tower and the clock tower of the terminal building. The antenna will be 680 feet long, and the natural period 850 meters.
    The voice transmission will be on 1600 meters. On this wavelength the antenna current will be between 20 and 25 amperes, representing approximately 3½ K.W., and the daylight range of the station will undoubtedly be in excess of 200 miles overland, representing 125,000 square miles.
    The radio station at Hoboken will be connected by direct wire to the ringside at Jersey City, and as the fight progresses, each blow struck and each incident, round by round, will be described by voice, and the spoken words will go hurtling through the air to be instantaneously received in the theatres, halls and auditoriums scattered over cities within an area of more than 125,000 square miles.
    Through the courtesy of Tex Rickard, promoter of the big fight, voice-broadcasting of the event is to be the means of materially aiding the work of the American Committee for Devastated France and also the Navy Club of the United States. These organizations will share equally in the contributions secured by large gatherings in theatres, halls and other places. The amateur radio operators of the country are to be the connecting link between the voice in the air and these audiences. The entire broadcasting arrangements, both transmitting and receiving, are under the direction of the National Amateur Wireless Association, but there are no restrictions. Any amateur who is skilled in reception is eligible, whether or not he is a member of any organization.
    Representatives of the American Committee for Devastated France and the Navy Club are engaging halls and theatres for July 2. All financial arrangements are entirely within the hands of these two organizations, and all admission charges are fixed by them. All arrangements of that kind are being rapidly completed.
    As theatres, halls and auditoriums are secured in the sixty-one cities, assignments of skilled amateur wireless operators will be made.
    The assignment of amateur radio operators who desire to participate in this greatest of all sporting events and this unprecedented undertaking of voice broadcasting, and who are willing to voluntarily assist in this most worthy cause, will be made in accordance with their qualifications, which, necessarily, must be of the highest type.
    In participating in this great event, unparalleled in the annals of sport or the history of radio communication, the amateur will be identified with an undertaking which has for its object the rehabilitation of the devastated regions of France, and to provide for the comfort and happiness of the men of our navy when off duty--objects which most certainly should appeal to the patriotism of every amateur.
    At a joint meeting of executives of the American Committee for Devastated France and the Navy Club a resolution was passed suggesting that recognition of the services of the amateurs be issued in permanent form. This resolution has been embodied in a certificate which will be presented to each amateur participating in the radiophone broadcasting.
    In effect, it officially testifies to the expert assistance rendered voluntarily by its holder, and his essential participation in the reception of broadcasted radiophone reports employed in this manner for the first time in history, making possible the successful accomplishment of the following objects:
    Promotion of amity between the nations represented in the greatest international sporting event on record.
    The scientific triumph of simultaneous transmission of the human voice without the aid of wires to audiences in many cities.
    The contribution of financial and material aid in the task of rehabilitating the war-torn and devastated regions of France.
    Aiding establishment and maintenance of a home, hotel and club for enlisted men of the United States Navy and Marine Corps.
    It will bear the signatures of Tex Rickard, Georges Carpentier, Jack Dempsey, Miss Anne Morgan and Franklin D. Roosevelt.
    In small cities, towns, villages, hamlets or private homes amateur operators can actively participate in the furtherance of this unprecedented undertaking in the way of inviting small gatherings of their friends to listen to the voice description of the big fight. This only applies, of course, in locations where halls are not secured by the American Committee for Devastated France and the Navy Club and the arrangements handled by these organizations.
    In the case of these small gatherings it is suggested that amateurs can take up a voluntary contribution, and any amount made up in this way will be acceptable, and will be appreciated. Money collected in this way should be sent to the office of the National Amateur Wireless Association, 326 Broadway, New York. Full acknowledgment of all such contributions, with the name and address of the amateur in charge of such local arrangements, will appear in the columns of THE WIRELESS AGE.
    All money received in this way will be immediately turned over to the Committee for Devastated France and the Navy Club, who will acknowledge its receipt through these columns.