Area of Dominant Influence.  Also known as DMA.

Above Mean Sea Level.  A measurement that can refer to any point on a tower.

A device for increasing the power of a signal.  Power amplifiers on ENG vans are usually located at the top of the mast.  (See also LNA)

A continuously variable signal which is either Amplitude Modulate (AM) or Frequency Modulated (FM).  Transmission is visually depicted as a "wave" form.

A component in the transmission or receive chain that focuses RF energy into a "beam."

Transmittal of RF energy at irregular time intervals, as typified by local area network data systems.  Asynchronous data UPCS devices operate at 1910-1920 MHz.

Broadcast Auxiliary Service, used generally here to refer to all broadcast licensees in the 1990 - 2110 MHz band. Applications of BAS include ENG, STLs and Relay Stations.

FCC-licensed television stations, LTTS, CARS and other licensees operating in 1990 - 2110 MHz.

A block of spectrum assigned to a transmission path.  For example, the current BAS "Channel 1" is the block of spectrum between 1990 MHz and 2008 MHz.

The process of using a device to limit a receiver to a strict frequency spectrum.  For example, a BAS channel 3 filter keeps the receiver from receiving any frequencies below 2025 MHz and above 2042 MHz.

Cable Television Relay Service.  Fixed or mobile station used for the transmission of television and related audio signals from the point of reception to a terminal point from which the signals are distributed to the public.  BAS spectrum in the 1.9 GHz band is authorized for use by CARS and LTTS.

Coded Orthogonal Frequency Division Multiplexing.  See Transmission Method.

A device that reverses the encoding process.  As part of video channel compression, decoders replace information lost during the encoding process based on an algorithm to restore the appearance of picture elements removed in the encoding process.

Uses discrete values instead of a continuous spectrum of values.  Transmission is typically thought of in the form of "0s and 1s."

The process of converting from analog to digital transmission technology involving Digital Encoding and changing the Transmission Method.

The process of video compression using encoders and decoders allowing a broadcaster to transmit more pictures (data) in narrower bandwidth.  See also MPEG.

Designated Market Area.  Also known as ADI or TV market.  A group of counties in the United States that is covered by a specific group of television stations.  A.C. Nielsen Media Research coined the term and there are 210 DMAs in the United States.  The size of a DMA is determined by the number of households served by the TV stations within that area and the percentage of the area's population in relation to the total population of the United States.  These figures are then used by Nielsen to determine ratings for specific television shows and stations.

Digital Video Broadcast-Terrestrial.  A type of signal modulation.

A device used to encode a signal or data into a form that is acceptable for transmission.  Encoding creates video channel compression.  Encoders use algorithms to remove picture elements in a video feed.

Electronic News Gathering, also known as TVPU. ENG mobile units transmit television signals to receive sites.

Forward Error Correction.  Allows the decoder to "fix" errors in bit transmission

Fixed Link Service.  Fixed links operate from one fixed point to another. Examples of a fixed link are:  STL, TSL, ICR, Translator Relay, and Booster Relay.  Fixed links are always single-channel, do not operate by remote control, have stationary dishes and are channel filtered.

Intra-City Relay.  Fixed service used to transmit signal between a TX and an RX.  ICRs and STLs can be licensed at 2 GHz, 7GHz, 13GHz, 18 GHZ or 23 GHz.  As higher frequencies are used for fixed links, the path length will necessarily be shorter and shorter wavelengths dissipate their power more rapidly over a long distance.

Transmit RF energy at a regular interval, typified by time-division voice systems.  Isochronous voice UPCS devices operate at 1920-1930 MHz.

High frequency RF (>1GHz) does not transmit through solid objects.  The transmitter must "see" the receiver in order to complete the path.  On very long shots (>30 miles), the curvature of the Earth can become a factor.

Low Noise Amplifier.  A special type of amplifier used in communication systems to amplify very weak signals captured by an antenna.  It is usually located at the receive antenna.  LNAs are also used to compensate for the signal loss from the receive antenna down a long length of cable (coming down off a 100-foot tower, for example)

Local Television Transmission Service.  Common Carrier (for hire) operators that usually have their own RXs and TXs are allowed to use this license to rent microwave services to broadcast licensees.  BAS spectrum in the 1.9 GHz band is authorized for use by CARS and LTTS.

The extendable and retractable pole on top of an ENG mobile unit, which carriers and antenna and amplifier, and typically range from 32 to 58 feet high.  These masts can also be mounted on trailers or in special cases on buildings.

Megahertz.  A measure of RF (radio frequency).  The old term was "megacycles," or one million cycles (waves) per second.

A mix of the studio output without the audio contribution from the remote location.  If the reporter just listened to the straight output of the studio "off-air," the reporter's own voice would be heard transmitted to the studio and then sent back to the location.  The reporter hears everything being transmitted from the studio "less" his/her own voice.  Also known as cleanfeed, reverse audio, return audio, talent queuing or interrupted fold back.

A video and audio compression standard used during Digital Encoding.  The acronym is short for Moving Picture Experts Group.  The current broadcast standard for video encoding is known as MPEG-2.

Mobile Satellite Services.  A radio communication service: (1) between mobile Earth stations and one or more space stations, or between space stations used by this service; or (2) between mobile earth stations, by means of one or more space stations.  This service may also include feeder links necessary for its operation.  As part of the new spectrum plan, MSS licensees may operate between 1995 MHz to 2025 MHz.

Association for Maximum Service Television. One of the groups representing broadcast interests.

National Association of Broadcasters. One of the groups representing broadcast interests. It is a lobbying organization for over-the-air broadcasters and major television networks.

National Telecommunications and Information Administration.  The Federal spectrum manager and the principal Executive Branch advisor on telecommunications policy.

The assembly that is used to protect the cables that travel up the pneumatic mast from inside the ENG truck to the equipment at the top of the mast.  This has taken the brand name of the red plastic cable sleeve, Nycoil.  The equipment can include transmitters, antennas, power amplifiers and/ TV cameras

ENG truck masts are lifted using a compressed air, or pneumatic system.  An air compressor located inside the ENG truck lifts the mast via remote control and shuts off when the mast is full of air or fully extended.

See RF.

Re-transmits TV signals.

Central receive systems are usually mounted on top of a tall building, mountaintop or tall tower that may be several miles away from the TV station. Broadcasters need to be able to steer the antenna, turn on and off a receiver, and/or pan and tilt a "tower cam." The remote control "master" is computer-based equipment located at a TV station that communicates with a Remote Control Slave, which is located at the tower.

Equipment located at tower that manages a RX Dish, RX, LNA, Tower Cams and Lights.  The Remote Control Master located at a studio usually operates it, but in case of data line failure, it can be operated manually.

Radio Frequency.  Refers to that portion of the electromagnetic spectrum in which electromagnetic waves can be generated by alternating current fed to an antenna.

Receiver.

Society of Broadcast Engineers. One of the groups representing broadcast interests. The SBE is comprised of radio and TV engineers (as opposed to video engineers, who belong to a different organization). The SBE frequency coordinator in a TV market (DMA) is responsible for making sure that licensees using radio frequencies in frequency bands allotted to broadcasters don't interfere with one another.

Studio-to-Transmitter Links, which carry a TV station's audio and video from the studio to broadcast tower, can be microwave or fiber.

For-hire ENG truck.  Some use licensed spectrum and others use station licenses.  They generally transmit to a broadcast station's central RX.

An over-the-air transmitting station that broadcasts both audio and video to television receivers in a particular area.  Individual television stations are usually granted licensees by the FCC to use a particular section of the radio spectrum (a channel) through which they send their signals.   TV stations in densely populated metro areas usually have only one transmitter.  TV stations in more spread-out, rural areas may use a microwave relay network to a number of transmitters in the region.  The Albuquerque market is an excellent example of a microwave network.

Refers to all land-based microwave.  Satellite transmit and receive frequencies are also in the UHF band (C-band is at 4/6GHz and Ku-Band is at 11/13GHz), so the "terrestrial" distinguishes the land-based microwave from the satellite microwave.

A camera mounted to a tower that takes video shots for the TV station.  Often, they are used in a newscast to take video of traffic, "beauty shots," or weather phenomena.

How a signal is broadcast.  Analog TV and microwave transmission uses Frequency Modulation (FM).  Digital TV transmission uses a method called Vestigial Side-Band (8VSB).  Digital Microwave transmission uses a method called Coded Orthogonal Frequency Multiplexing (COFDM).

Transmitter-to-Studio Links, which carry a signal from a transmitter to the studio, can be microwave or fiber.  TSLs can be licensed at 2 GHz, 7GHz, 13GHz, 18 GHZ or 23 GHz.   The higher the frequency, the shorter the path.

Television Pick Up.  Also known as ENG.

Transmitter.

Unlicensed Personal Communications Service.  The current allocation is 1910-1930 MHz.

Frequency coordinator for UPCS bands.

Vestigial Side Band.  Like COFDM, FM and DVB-T, it is a method of RF transmission.  VSB is most often used for digital over-the-air TV transmitters that air High-Definition programming.