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.
AN/UPN-1
Radar beacon AN/UPN-1, sometimes known as BUPS (Beacon, Ultra Portable, S-band), is an ultra-portable radio beacon for ground, paratroop or shipboard use having a range of 35 to 50 miles. The set is capable of being interrogated by airborne radars operating on beacon function and replying with a coded signal permitting the beacon to be located in range and azimuth. It is capable of transmitting five different codes, it transmits on 3256 Mc. (Megacycles [per second], now MHz (Megahertz)) and receives on 3333 Mc. peak power output is 50 Watts.