Automatic transmission system

Last updated

An automatic transmission system (ATS) is an automated system designed to keep a broadcast radio or television station's transmitter and antenna system running without direct human oversight or attention for long periods. Such systems are occasionally referred to as automated transmission systems to avoid confusion with the automatic transmission of an automobile.

Contents

History

Traditionally, radio and television stations were required to have a licensed operator, technician or electrical engineer available to tend to a transmitter at all times it was operating or capable of operating. Any condition (such as distorted or off-frequency transmission) that could interfere with other broadcast services would require immediate manual intervention to correct the fault or take the transmitter off the air. Facilities also had to be monitored for any fault conditions which could impair the transmitted signal or cause damage to the transmitting equipment. [1]

Because broadcast transmitters were often at a different location from the broadcast studios, attended operation required an operator to be physically located at the transmitter site. In the 1950s and 1960s, remote control systems were introduced to allow an operator at the studio to power the transmitter on or off. [1] At the same time, an early remote control system, the Automon, was developed by RCA engineers in Montréal that included a relay system that automatically detected if the transmitter was operating outside of its allowed parameters. The Automon could send the studio an alarm if the transmitter was out of tolerance and, if contact to the studio was lost, it could automatically power down the transmitter. [2] A similar system was developed in 1953 by Paul Schafer in California, using a rotary telephone to raise or lower transmitter parameters remotely. [3]

As technology improved, transmitters became more reliable, and electromechanical means of checking and later correcting problems became commonplace. Regulations eventually caught up with these advances, to allow of unattended operation via an ATS. [1] During the 1970s, the BBC made widespread use of automated systems on its UHF television network to switch from main to standby transmitters in the case of a fault, as well as to alert engineering staff to problems. [4] In 1977, the U.S. Federal Communications Commission loosened operation rules to allow stations in the United States with ATSes to automatically monitor transmitter operation and allow the ATS to automatically adjust modulation or shutdown the transmitter if operation was out of tolerance, [1] [5] although the specific rules have continued to evolve with changes to the Emergency Alert System and the introduction of digital radio. [6]

Theory of operation

An ATS monitors conditions such as voltage, current, and temperature within the transmitter cabinet or enclosure, and often has external sensors as well, particularly on the antenna. Some systems have remote monitoring points which report back to the main unit through telemetry links. [7]

Advanced systems can monitor and often correct other problems which are considered mission-critical, such as detecting ice on antenna elements or radomes and turning on heaters to prevent the VSWR (power reflected from a mismatched antenna back into the transmitter) from going too high. High-power stations that use desiccation pumps to put dry nitrogen into their feedline (to displace moisture for increased efficiency) can also monitor the pressure. Generators, batteries, and incoming electricity can also be monitored. [7]

If anything goes wrong which the ATS cannot handle, it can send out calls for help, via pager, telephone voice message, or dedicated telemetry links back to a fixed point such as a broadcast studio. Other than possibly listening for dead air from the studio/transmitter link, an ATS does not cover the programming or the studio equipment like broadcast automation, but rather only the "transmitter plant". [7]

An ATS can also be used to automate scheduled tasks, such as lowering an AM radio station's transmission power at sundown and raising it at sunrise to meeting license requirements for different propagation patterns at day and night. [1]

Related Research Articles

<span class="mw-page-title-main">Transmitter</span> Electronic device that emits radio waves

In electronics and telecommunications, a radio transmitter or just transmitter is an electronic device which produces radio waves with an antenna. The transmitter itself generates a radio frequency alternating current, which is applied to the antenna. When excited by this alternating current, the antenna radiates radio waves.

<span class="mw-page-title-main">Radiotelephone</span> Communications system for transmission of speech over radio

A radiotelephone, abbreviated RT, is a radio communication system for conducting a conversation; radiotelephony means telephony by radio. It is in contrast to radiotelegraphy, which is radio transmission of telegrams (messages), or television, transmission of moving pictures and sound. The term is related to radio broadcasting, which transmit audio one way to listeners. Radiotelephony refers specifically to two-way radio systems for bidirectional person-to-person voice communication between separated users, such as CB radio or marine radio. In spite of the name, radiotelephony systems are not necessarily connected to or have anything to do with the telephone network, and in some radio services, including GMRS, interconnection is prohibited.

A studio transmitter link sends a radio station's or television station's audio and video from the broadcast studio or origination facility to a radio transmitter, television transmitter or uplink facility in another location. This is accomplished through the use of terrestrial microwave links or by using fiber optic or other telecommunication connections to the transmitter site.

<span class="mw-page-title-main">Radio receiver</span> Device for receiving radio broadcasts

In radio communications, a radio receiver, also known as a receiver, a wireless, or simply a radio, is an electronic device that receives radio waves and converts the information carried by them to a usable form. It is used with an antenna. The antenna intercepts radio waves and converts them to tiny alternating currents which are applied to the receiver, and the receiver extracts the desired information. The receiver uses electronic filters to separate the desired radio frequency signal from all the other signals picked up by the antenna, an electronic amplifier to increase the power of the signal for further processing, and finally recovers the desired information through demodulation.

Broadcast engineering is the field of electrical engineering, and now to some extent computer engineering and information technology, which deals with radio and television broadcasting. Audio engineering and RF engineering are also essential parts of broadcast engineering, being their own subsets of electrical engineering.

Broadcast automation incorporates the use of broadcast programming technology to automate broadcasting operations. Used either at a broadcast network, radio station or a television station, it can run a facility in the absence of a human operator. They can also run in a live assist mode when there are on-air personnel present at the master control, television studio or control room.

A broadcast transmitter is an electronic device which radiates radio waves modulated with information content intended to be received by the general public. Examples are a radio broadcasting transmitter which transmits audio (sound) to broadcast radio receivers (radios) owned by the public, or a television transmitter, which transmits moving images (video) to television receivers (televisions). The term often includes the antenna which radiates the radio waves, and the building and facilities associated with the transmitter. A broadcasting station consists of a broadcast transmitter along with the production studio which originates the broadcasts. Broadcast transmitters must be licensed by governments, and are restricted to specific frequencies and power levels. Each transmitter is assigned a unique identifier consisting of a string of letters and numbers called a callsign, which must be used in all broadcasts.

Power-system automation is the act of automatically controlling the power system via instrumentation and control devices. Substation automation refers to using data from Intelligent electronic devices (IED), control and automation capabilities within the substation, and control commands from remote users to control power-system devices.

A television station is a set of equipment managed by a business, organisation or other entity, such as an amateur television (ATV) operator, that transmits video content and audio content via radio waves directly from a transmitter on the earth's surface to any number of tuned receivers simultaneously.

<span class="mw-page-title-main">WLSO</span> Radio station in Sault Ste. Marie, Michigan

Laker Radio is an internet radio station in Sault Ste. Marie, Michigan, United States. Broadcasting a college radio format, The 46th Parallel Radio is the campus radio station of the city's Lake Superior State University, and also provides mobile DJ services for on-campus and Sault Ste. Marie events. From 1993–2017, the station broadcast at 90.1 on the FM dial with the call sign WLSO, before becoming solely an internet radio station during the 2016–2017 school year.

<span class="mw-page-title-main">Airport surveillance radar</span> Radar system

An airport surveillance radar (ASR) is a radar system used at airports to detect and display the presence and position of aircraft in the terminal area, the airspace around airports. It is the main air traffic control system for the airspace around airports. At large airports it typically controls traffic within a radius of 60 miles (96 km) of the airport below an elevation of 25,000 feet. The sophisticated systems at large airports consist of two different radar systems, the primary and secondary surveillance radar. The primary radar typically consists of a large rotating parabolic antenna dish that sweeps a vertical fan-shaped beam of microwaves around the airspace surrounding the airport. It detects the position and range of aircraft by microwaves reflected back to the antenna from the aircraft's surface. The secondary surveillance radar consists of a second rotating antenna, often mounted on the primary antenna, which interrogates the transponders of aircraft, which transmits a radio signal back containing the aircraft's identification, barometric altitude, and an emergency status code, which is displayed on the radar screen next to the return from the primary radar.

The first Schafer Automation System, installed at KGEE(AM) in Bakersfield, California in 1956, was dubbed the "blue-wire job" because all of the wiring in it was blue, its inventor, Paul Schafer said. "The owner wanted to program his station all night long without a person being there. I used a couple of Seeburg record player changers to play 45s and several Ampex reel decks for commercials and we were in business," Schafer said.

<span class="mw-page-title-main">Citizen Weather Observer Program</span> Network of weather stations based in the United States

The Citizen Weather Observer Program (CWOP) is a network of privately owned electronic weather stations concentrated in the United States but also located in over 150 countries. Network participation allows volunteers with computerized weather stations to send automated surface weather observations to the National Weather Service (NWS) by way of the Meteorological Assimilation Data Ingest System (MADIS). This data is then used by the Rapid Refresh (RAP) forecast model to produce short term forecasts of conditions across the contiguous United States. Observations are also redistributed to the public.

<span class="mw-page-title-main">Central apparatus room</span> Room where shared broadcast equipment is located

In broadcast facilities and television studios, a central apparatus room, central machine room, or central equipment room (CER), or central technical area (CTA), or rack room is where shared equipment common to all technical areas is located. Some broadcast facilities have several of these rooms. It should be air-conditioned, however low-noise specifications such as acoustical treatments are optional. Equipment is connected either directly with an attached foldout monitor, keyboard and mouse or remotely via KVM switch, SSH, VNC, RS-232 or remote desktop.

<span class="mw-page-title-main">Radio</span> Technology of using radio waves to carry information

Radio is the technology of signaling and communicating using radio waves. Radio waves are electromagnetic waves of frequency between 3 hertz (Hz) and 3,000 gigahertz (GHz). They are generated by an electronic device called a transmitter connected to an antenna which radiates the waves, and received by another antenna connected to a radio receiver. Radio is widely used in modern technology, in radio communication, radar, radio navigation, remote control, remote sensing, and other applications.

In terrestrial radio and television broadcasting, centralcasting refers to the use of systems automation by which customised signals for broadcast by multiple individual stations may be created at one central facility.

<span class="mw-page-title-main">RF module</span>

An RF module is a (usually) small electronic device used to transmit and/or receive radio signals between two devices. In an embedded system it is often desirable to communicate with another device wirelessly. This wireless communication may be accomplished through optical communication or through radio-frequency (RF) communication. For many applications, the medium of choice is RF since it does not require line of sight. RF communications incorporate a transmitter and a receiver. They are of various types and ranges. Some can transmit up to 500 feet. RF modules are typically fabricated using RF CMOS technology.

<span class="mw-page-title-main">Communications-based train control</span> Railway signaling system

Communications-based train control (CBTC) is a railway signaling system that uses telecommunications between the train and track equipment for traffic management and infrastructure control. CBTC allows a train's position to be known more accurately than with traditional signaling systems. This makes railway traffic management safer and more efficient. Metros are able to reduce headways while maintaining or even improving safety.

<span class="mw-page-title-main">Ground segment</span> Ground-based elements of a spacecraft system

A ground segment consists of all the ground-based elements of a space system used by operators and support personnel, as opposed to the space segment and user segment. The ground segment enables management of a spacecraft, and distribution of payload data and telemetry among interested parties on the ground. The primary elements of a ground segment are:

References

  1. 1 2 3 4 5 Hallikainen, Harold (1996). "Regulatory History of Operator Licenses and Transmitter Remote Control" (PDF). The NAB Guide to Unattended Station Operation: How to Run Your Transmitter Without an Operator. Washington, D.C.: National Association of Broadcasters. ISBN   0-89324-247-0. OCLC   41334048.
  2. Potts, Lyman; Norton, Robert (2003). "Unattended Transmitter Operation — The Automon". History of Canadian Broadcasting. Canadian Communications Foundation. Retrieved October 30, 2022.
  3. Stine, Randy J. (June 1, 2016) [2002-04-10]. "From the Archives: NAB Honors 'Father of Automation'". Radio World .
  4. "The Unattended Operation of U.H.F. Broadcasting Transmitters". BBC Engineering. No. 85. January 1971. pp. 2–3 via Internet Archive.
  5. "Unattended Operation of Radio and Television Stations". Federal Communications Commission. December 13, 2015. Retrieved October 30, 2022.
  6. Stimson, Leslie (July 4, 2007). "FCC Looks at Changes to Rules Covering Unintended Operation" (PDF). Radio World. p. 3 via World Radio History.
  7. 1 2 3 Hallikainen, Harold (2007). "Transmitter Remote Control and Monitoring Systems". In Williams, Edmund A.; Jones, Graham A.; Layer, David H.; Osenkowsky, Thomas G. (eds.). National Association of Broadcasters Engineering Handbook (10th ed.). Burlington, Massachusetts: Focal Press. ISBN   978-0-240-80751-5. OCLC   858995417.

See also