WHCN (105.9 FM) is a commercial radio station licensed to Hartford, Connecticut. It broadcasts a classic hits radio format and is owned by iHeartMedia, Inc. It is called "The River 105.9," a reference to the Connecticut River. The studios and offices are on Columbus Boulevard in Hartford. The transmitter site is at West Peak State Park in nearby Meriden. In addition to a standard analog transmission, WHCN broadcasts using HD Radio technology. Its HD2 digital subchannel formerly played electronic dance music and was known as "Club Jam EDM." WHCN is one of the oldest FM stations, beginning as an experimental outlet in 1939. Signal WHCN is a Class B FM station. It would normally transmit at 50,000 watts ERP (Effective Radiated Power) at a HAAT (Height Above Average Terrain) of 150 meters. Because WHCN's tower is 264 meters, it is limited to an ERP of 16,000 watts, in order to maintain an equivalent coverage area. Its signal is radiated using a directional pattern, with the maximum sent toward Hartford at 30° azimuth. It is reduced in other directions, and weakest toward the southwest, at 190° and 230° azimuth. This is done to avoid interference with WQXR-FM, also on 105.9 MHz, whose transmitter is in New York City. In those directions, the signal is .45 of full power, or 7,200 watts; WQXR operates with reduced power (610 watts at 416 meters) to avoid interfering with WHCN. History Experimental authorization In the 1930s, experiments were begun into establishing radio stations broadcasting on "Very High Frequency" (VHF) assignments above 30 MHz. Reception of stations operating on these frequencies tended to be limited to line-of-sight distances, so placing the transmitting antenna at as high an altitude as possible provided maximum coverage. Stations operating on these higher frequencies were known informally as "Apex" stations, and initially employed "amplitude modulation" (AM) transmissions like those used in the standard AM broadcast band. Franklin M. Doolittle, the owner of AM station WDRC in Hartford, obtained permission to establish an experimental Apex station, W1XSL, with a transmitter site located on Meriden Mountain. Another innovation during the 1930s was the introduction of a competing transmission technology, "wide-band frequency modulation" (FM), which was developed in the United States by Edwin Howard Armstrong. This was promoted as being superior to AM transmissions, in particular due to its high fidelity and near immunity to static interference. On June 17, 1936 Armstrong formally demonstrated