A radio station is a set of equipment necessary to carry on communication via radio waves. Generally, it is a receiver or transmitter, an antenna, and some smaller additional equipment necessary to operate them. Radio stations play a vital role in communication technology as they are heavily relied on to transfer data and information across the world.
More broadly, the definition of a radio station includes the aforementioned equipment and a building in which it is installed. Such a station may include several "radio stations" defined above (i.e. several sets of receivers or transmitters installed in one building but functioning independently, and several antennas installed on a field next to the building). This definition of a radio station is more often referred to as a transmitter site, transmitter station, transmission facility or transmitting station. An example of this definition is Bethany Relay Station of the Voice of America which had seven broadcast transmitters and could broadcast up to seven independent programs (even produced by different broadcasters) simultaneously, as well as several communications transmitters and receivers.
The International Telecommunications Union, defines a radio (communication) station as - «one or more transmitters or receivers or a combination of transmitters and receivers, including the accessory equipment, necessary at one location for carrying on a radiocommunication service, or the radio astronomy service. Each station shall be classified by the service in which it operates permanently or temporarily».
Equipment for a radio station
- Transmitter - Takes the electrical output of a microphone and then modulates a higher-frequency carrier signal and transmits it as radio waves.
- Receiver - The broadcast message is received by the receiver and decodes the radio sine waves.
- Antenna - An antenna is required for transmission; it is also required to receive radio waves. The main use of an antenna is to send radio signals.
- Aerial feeder - system of feeding HF-Energy (power) in the antenna
- Transmission lines - Transmission lines are used to transfer the radio signals from one location to another. For example, a transmission line was used in Luftwaffe, Germany during WW II to send information from camps back to their base.
- Connectors Interface panel remote control – This is used to connect various different types of the equipment used in a radio station. To input broadcast data into a transmitter an interface panel will need to be used.
- Cable – A cable can be used to connect the various devices.
- Equipment Rack – To hold all equipment in a secure and logical manner, an equipment rack will be used.
- Power protection equipment – For holding equipment's in a stable, secure and logical manner.
- UPS – For uninterrupted power supply.
These are the most used/important devices and items for most radio stations.
A microphone is used to capture the input of sound waves created by people speaking into the device. The sounds are then turned into electrical energy; this energy then flows along a metal antenna. As the electrons in the electric current move back and forth up the antenna, the current creates an invisible electromagnetic radiation in the form of radio waves. The waves travel at the speed of light, taking the radio program (voices recorded) with them.
A compound of both a transmitter and a receiver is called a transceiver, they are combined and share common circuitry or a single housing. When no circuitry is common between the transmit and receive functions, the device becomes a transmitter-receiver.
Technically transceivers must combine a significant amount of the transmitter and receiver handling the circuitry.
Communication technology is an umbrella term which includes any communication device or application containing:
- Cellular phones
- Computer and network hardware and software
- Satellite systems
Radio frequency list
- Broadcasting service (AM sound broadcasting) - 535 to 1 606.5 kHz
- Broadcasting service (HF sound broadcasting) - bands from 5.9 to 26.1 MHz
- Mobile service (citizens band radio) - 26.96 to 27.41 MHz
- Broadcasting service (television, channels 2 through 6) - 54 to 88 MHz
- Broadcasting service (FM sound broadcasting) - 88 to 108 MHz
- Broadcasting service (television, channels 7 through 13) - 174 to 220 MHz
- FIXED SERVICE, MOBILE SERVICE, (generic frequency allotment) garage door opener - around 40 MHz
- MOBILE SERVICE (generic frequency allotment) standard digidal cordless phones (DECT) - 40 to 50 MHz
- MOBILE SERVICE baby monitors - 49 MHz
- MOBILE SERVICE radio controlled airplanes - around 72 MHz
- Mobile service cell phones - 824 to 849 MHz
- Space research service (deep space) - 2290 MHz to 2300 MHz
Broadcasting service (short: Broadcasting (BS) | also: broadcasting radiocommunication service) is – according to Article 1.38 of the International Telecommunication Union´s (ITU) Radio Regulations (RR) – defined as «A radiocommunication service in which the transmission are intended for direct reception by the general public. This service may include sound transmissions, television transmissions or other types of transmission (CS).» Definitions identical to those contained in the Annexes to the Constitution and Convention of the International Telecommunication Union (Geneva, 1992) are marked "(CS)" or "(CV)" respectively.
Broadcasting began with AM sound broadcasting, before this all form of electronic communications, radio communication, telephone etc. were "one-to-one" with the message intended for a single recipient.
The broadcasting station is usually associated with wireless transmission, though in practice broadcasting transmission (sound and television) take place using both wires and radio waves. The point of this is that anyone with the appropriate receiving technology can receive the broadcast.
Types of broadcasting stations
In line to ITU Radio Regulations (article1.61) each broadcasting station shall be classified by the service in which it operates permanently or temporarily.
FM broadcasting stations operate in the frequency band allocated to the Broadcasting service in the range of 88 to 108 MHz on primary basis. The particular broadcasting channels are in line to the regional or national frequency allotment plans and subject to frequency coordination. The interference criteria, established by the ITU Radio Regulations, are mandatory, so the highest quality reception might be achieved. Any frequency assignment is within the responsibility of the competent national Frequency assignment authority.
- Low power FM broadcasting
A low power FM broadcasting station (also low power FM radio) is operated at a power of 500 mW to 100W and can cover a service radius of 3 to 10 miles (geographical). Normally it broadcasts educational content; and is not allowed to undertake any commercial operations.
The lower the transmission frequency of AM sound broadcasting stations (also: AM radio), the greater is the geographical area covered, and lower is the quality of AM reception. Typical AM radio stations broadcast at frequencies between 525 kHz and 1605 kHz.
AM radio reception faces high interference from other radiocommunication services, allocated to the particular frequency band, or local broadcasts at similar frequencies, usually originating from other countries. To set up an AM broadcasting transmitter needs a massive infrastructure investment, usually including the cost of hiring more than one cross-border frequency coordination to comply with each country's regulations.
Internet (sound or television) broadcasting (short: Internet radio) is one of the least expensive methods to provide sound or television programmes to a worldwide audience. The only thing that is required is a computer with a large storage capacity. A high speed internet connection may also be needed and funds to purchase software.
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- "How do antennas and transmitters work? - Explain that Stuff". www.explainthatstuff.com. Retrieved 2015-11-03.
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- ITU Radio Regulations, Section IV. Radio Stations and Systems – Article 1.38, definition: broadcasting service / broadcasting radiocommunication service
- Neira, Bob. "Broadcasting". modestoradiomuseum. modestoradiomuseum.