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.
All India Radio
The external services of AIR are also broadcast to Europe in DRM (Digital Radio Mondiale) on 9950 kHz between 1745–2230 UTC. These external transmissions are broadcast by high-power transmitters located at Aligarh, Bengaluru, Chennai, Delhi, Gorakhpur, Guwahati, Mumbai and Panaji on shortwave and from Jalandhar, Kolkata, Nagpur, Rajkot and Tuticorin on medium wave. Soon All India Radio Amritsar will also start a booster service on the FM band. Some of these transmitters are 1000 kW (1 MW) or 500 kW. Programs are beamed to different parts of the world except for the Americas and the reception quality is very good in the target areas. In each language service, the program consists of news, commentary, a press review, talks on matters of general or cultural interest, feature programmes, documentaries and music from India and the target region. Most programs originate at New Broadcasting House on Parliament Street in New Delhi, with a few originating at SPT Bengaluru, Chennai, Hyderabad, Jalandhar, Kolkata, HPT Malad Mumbai, Thiruvananthapuram and Tuticorin.