About Our Tower
LAST UPDATED: SEP 06, 2016 12:46PM EDT
WAMU broadcasts from a tower located on American University's campus near the corner of Nebraska and Massachusetts Avenues in upper Northwest Washington. The tower is a four-legged self-supporting structure originally erected for TV channel 7 in 1947. It was turned over to American University in the early 1960s. The geographic coordinates are North Latitude 38-56-10 and West Longitude 077-05-33.
The tower is 319 feet tall. The pole on which the antennae are mounted and projects through the top of the tower extends the height to 428 feet. The center of radiation from WAMU's six bay Shively FM antenna is 499 feet above average terrain. WAMU also has an auxiliary antenna lower on the tower in case of a failure of the main antenna. Ground elevation in the Tenleytown area of Washington, the highest point in the District, is 410 feet. Television and FM reception requires line-of-site between the transmitting and receiving antennae which is why most of the TV and FM transmission facilities in the Washington area are located in or near Tenleytown.
WAMU has two solid-state Nautel transmitters rated at 10kW each, the outputs of which are combined to produce the 17kW transmitter power output. If either transmitter fails the one remaining transmitter is automatically switched into the antenna with minimal interruption of service. Each transmitter has six modules and a failure of any one only reduces the power by a small amount.
WAMU also transmits a HD Radio(c) signal with a Harris solid-state transmitter combined with the analog signal into the existing antenna. HD Radio(c) is a new development for producing a near CD quality audio without the annoying tics, pops and other artifacts of analog FM broadcasts. The digital transmitter has a power output of 1,750 Watts (1.75kW). After combining with the analog signal the power is 170 Watts. This much lower power provides a HD Radio(c) service area roughly equivalent to the service area of the analog FM system.