KDKA in Pittsburgh was the first commercial radio station in the United States, having made their first broadcast in November 1920. By 1925 there were over 500 broadcast stations in the United States. KDKA was operated by Westinghouse Electric to help sell radio receivers. In addition to radio equipment manufacturers, many publishers were starting stations. Experimenter Publishing applied for and was granted a radio station license to transmit at 1160 kilocycles (kHz) with the call sign WRNY. (Over the next three years they would use 800 kHz, 1070 kHz, 970 kHz, 920 kHz and finally 1010 kHz.) The state of the art studio was in a room on the 18th floor of the Roosevelt Hotel in New York City and the 500 watt transmitter located on the hotel roof. The first broadcast was on June 12, 1925 and was reported in the "New York Times". The opening speaker was former Senator Chauncey Depew followed by the "father of radio", Lee De Forest. This was followed by live musical entertainment. The "Times" noted Hugo Gernsback's Staccatone signal generator that was used before the station signed on and signing the end of programs. The Staccatone was a primitive music synthesizer described in the March 1924 "Practical Electrics" magazine. Experimenter Publishing used the radio station and the magazines to promote each other. The station call letters, WRNY, appeared on each magazine cover.