WNBC (channel 4) is a television station in New York City, serving as the flagship of the NBC network. It is owned and operated by the network's NBC Owned Television Stations division alongside Linden, New Jersey–licensed Telemundo station WNJU (channel 47). WNBC's studios and offices are co-located with NBC's corporate headquarters at 30 Rockefeller Plaza in Midtown Manhattan; WNJU's facilities in Fort Lee, New Jersey, also serve as WNBC's New Jersey news bureau. Through a channel sharing agreement with WNJU, the two stations transmit using WNJU's spectrum from an antenna atop One World Trade Center. WNBC holds the distinction as the oldest continuously operating commercial television station in the United States. History Experimental operations What is now WNBC traces its history to experimental station W2XBS, founded by the Radio Corporation of America (RCA, a co-founder of the National Broadcasting Company), in 1928, just two years after NBC was founded as the first nationwide radio network. Originally a test bed for the experimental RCA Photophone theater television system, W2XBS used the low-definition mechanical television scanning system. Later it was used mostly for reception and interference tests. The call letters W2XBS meant W2XB-south, with W2XB being the call letters of the first experimental station, started a few months earlier at General Electric's (GE) main factory in Schenectady, New York, which evolved into today's WRGB. GE was the parent company of both RCA and NBC, and technical research was done at the Schenectady plant. The station originally broadcast on the frequencies of 2.0 to 2.1 MHz. In 1929, W2XBS upgraded its transmitter and broadcast facilities to handle transmissions of sixty vertical lines at twenty frames per second, on the frequencies of 2.75 to 2.85 MHz. In 1928, Felix the Cat was one of the first images ever broadcast by television when RCA chose a papier-mâché (later Bakelite) Felix doll for an experimental broadcast on W2XBS. The doll was chosen for its tonal contrast and its ability to withstand the intense lights needed in early television. It was placed on a rotating phonograph turntable and televised for about two hours each day. The doll remained on the turntable for nearly a decade as RCA fine-tuned the picture's definition, and converted to electronic television. The station left the air sometime in 1933 as RCA turned its attention to all-electronic cathode-ray tube (CRT) television research at its Camden, New Jersey facility, under the leadership of Dr.