Telecommunication
The other meaning of the term "channel" in telecommunications is seen in the phrase communications channel, which is a subdivision of a transmission medium so that it can be used to send multiple streams of information simultaneously. For example, one radio station can broadcast radio waves into free space at frequencies in the neighborhood of 94.5 MHz (megahertz) while another radio station can simultaneously broadcast radio waves at frequencies in the neighborhood of 96.1 MHz. Each radio station would transmit radio waves over a frequency bandwidth of about 180 kHz (kilohertz), centered at frequencies such as the above, which are called the "carrier frequencies". Each station in this example is separated from its adjacent stations by 200 kHz, and the difference between 200 kHz and 180 kHz (20 kHz) is an engineering allowance for the imperfections in the communication system.
Radio Tonga
The most far-reaching of all Radio Tonga's services, this channel broadcasts daily from 6am to midnight, on a frequency of 1017 kHz. This is the only service of TBC that has been in operation since TBC's inception in 1961. It features local, Pacific & international news, as well as Tongan music, and overseas retro music, mostly from the 1970s & 1980s. Several local church organisations and businesses have weekly programs, and, though it is government-owned and funded, a significant source of its profit relies on in-house commercial advertising. In the event of local emergencies, such as tropical cyclones, Radio Tonga has been known to stay on the air all night with constant cyclone updates from the Tonga Meteorological Service. Radio Tonga 1 can be heard throughout the entire Kingdom of Tonga, including the outer island groups of Ha'apai, Vava'u, Niuafo'ou & Niuatoputapu, although there have been reports of listeners receiving the signal in other countries, such as Samoa and Finland. The station broadcasts with a power output of 10,000 Watts into a non directional antenna.
Formerly known as FM97, now broadcasting on a frequency of 90.0 MHz, this commercial FM station commenced in the early 1990s, and now runs 24 hours a day, playing mostly chart-toppers from abroad. After the local broadcast ends at midnight, BBC programming is relayed live via satellite until the local broadcast resumes at 6am. This service can only be heard on the main island of Tongatapu, and its closely surrounding islands such as 'Eua, Pangaimotu and Atata. The station broadcasts with 500 watts.