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 Caroline
Radio Caroline announced a wavelength of 199 metres, rhyming with the name, but was actually broadcasting on 197.3 metres (1520 kHz). Stations in the UK announced the wavelength in metres, and radios at that time were tuned using an analogue dial. The absence of precise digital readouts allowed for some leeway between the precise transmission frequency and the channel announced on the air. The Dutch offshore station Radio Veronica was on 192 metres (1562 kHz) and Radio Atlanta broadcast on 201 (1493 kHz).