In the 1920s, roller chairs were common at tourist sites. These chairs could be rented, and visitors pushed from place to place to view the sights. W. Harold Warren's innovation of adding a radio receiver to a roller chair gained a fair amount of attention at the time. In fact, the next summer he was again featured, when the roller chair radio was used to pick up WJY's broadcast of the Dempsey-Carpentier fight.
According to this report, the broadcasts most commonly being received came from AT&T's experimental station, 2XJ, in Deal Beach, New Jersey.
Radio News, August, 1920, page 74:
The Radiophone on Roller Chairs
A New and Interesting Use of the Loop
VISITORS to Asbury Park, N. J. this season are being entertained with a most unique innovation introduced by W. Harold Warren in the form of a roller chair equipt to receive wireless telephone and telegraph signals as the passenger rolls merrily along the boardwalk.
Scores of boardwalk promenaders are attracted by the various demonstrations and are permitted to "listen-in." They hear the conversations and musical phonograph records which are transmitted by the Foxhurst station of the Deal Beach plant of the Western Electric Co. With this compact loop Mr. Warren has heard messages from stations as far south as Norfolk, Va., and as far north as New Haven, Conn. A recent test showed the received signals to be as distinct as tho a regular antenna had been used, allowing of course the reception of signals from stations of equal distances. The accompanying illustration is a photograph taken on the boardwalk of Asbury Park and shows Mr. Warren and his sisters, Misses Warren in the act of making tests preparatory to evening demonstrations. All of the equipment used is shown in the photograph except a set of A and B batteries which are located below the dashboard of the roller chair.
The apparatus is so compact that three persons can sit comfortably with it in the chair. It consists of a "loop," an audion detector, and an amplifier.
The "loop" is of the flat type and measures eighteen inches on each side. The cross supports and protecting frame are made of white pine lattice ¼ inch thick by 1¼ or 1½ inches wide. Each of the cross supports is 25½ inches long. A notch is cut in each support at the center and then joined so as to form an "X". Commencing 3½ inches from the center, saw cuts ½ inch apart are made on both edges on each of the four legs. Beginning at the first or inner saw cut No. 26 S. C. C. wire is wound tightly in a clockwise direction to the outer edge. The loop is then turned around, the wire crossed over the leg, and the winding continued in an anticlockwise direction on this side, back to the first saw cut. Two single Fahnestock connectors are then fastened to two of the legs--one connector on each--near the center. A cross strip is placed between the other two legs in the center of which a hole is bored about half way thru the strip. A hole of the same size is also bored in the center of the bottom protecting strip. A 3/8-inch dowel rod is inserted in the lower hole past upward between the windings to the cross strip. This allows the loop to be revolved. A set screw is inserted in the lower protecting strip to keep loop rigid in one direction, if desired. No coils are used, tuning being accomplisht solely with the variable condenser. There are 18 turns on each side of the loop and approximately 90 feet of wire is used. This size of loop is most effective for wavelengths from 300 to 500 meters but good results have been obtained on wavelengths up to 800 meters. Excellent results have been experienced with the apparatus in a moving auto and in buildings of all kinds of construction. As the radiophone stations of the Western Electric Co. at New York City and Deal Beach, N. J., are now operating on wavelengths close to 400 meters, this loop has proven most effective.