Television receive-only
Encyclopedia
Television receive-only, TVRO, or Big ugly dish (BUD), is a term used in North America
to refer to the reception of satellite television
from FSS
-type satellites, generally on C-band analog; free-to-air
and unconnected to a commercial DBS
provider. TVRO systems rely on feeds being transmitted unencrypted and using open-standards, which heavily contrasts to DBS systems in the region.
The term is rarely used in recent times due to the general move towards pay television and subscription-based DBS services like DirecTV
, Dish Network
, Bell TV, and Sky TV
, although it is still sometimes used to refer to receiving digital TV "backhaul" feeds from FSS
-type satellites.
TVRO was once the sole, and later the main means of consumer satellite reception in the United States
, until the mid-1990s and the arrival of services such as PrimeStar
, USSB
, DirecTV
, and Dish Network
. While these services are at least theoretically based on open standards (DVB-S
, MPEG-2
, MPEG-4
), the majority of services are encrypted and require proprietary decoder hardware.
Reception of free-to-air satellite signals, generally Ku band
Digital Video Broadcasting, for home viewing is still common in Europe, India and Australia, although the TVRO nomenclature was never used there.
Free-to-air satellite signals are also very common in the People's Republic of China
, as many rural locations cannot receive cable television
and solely rely on satellites to deliver television signals to individual homes.
A C-band dish (often given as BUD, for "big ugly dish") is a colloquial name
for a TVRO satellite dish
used to receive satellite
television
signals from FSS
-type satellites on the microwave
C band
. BUDs are usually 6½ to 12 feet or two to 3.5 meters in diameter
, and have been a source of much consternation (even local zoning
disputes) due to their perception as an eyesore
. Neighborhoods with restrictive covenant
s usually prohibit this size of dish, except where such restrictions are illegal.
and later models being made of wire
mesh
and solid steel
or aluminum. Fiberglass dishes are most commonly found on low rise commercial buildings, while the wire mesh counterparts are typically found on residential buildings. BUD systems of the time came at a high cost, usually several thousand dollars.
They work by receiving a low-power C-Band (3.7-4.2 GHz) frequency-modulated
analog television
signal directly from the original distribution satellite — the same signal received by cable-company headend
s. Because analog channels took up an entire transponder
on the satellite, and each satellite had a fixed number of transponders, dishes were usually equipped with a polar mount
and actuator
to sweep the dish across the horizon to receive channels from multiple satellites. Switching between horizontal and vertical polarization was accomplished by a small electric servo
motor which moved a probe inside the feedhorn throat at the command of the receiver (commonly called a "polarotor" setup). Higher-end receivers did this transparently, switching polarization and moving the dish automatically as the user changed channels.
Originally, all channels could be received in the clear
(ITC) and free of charge. In 1986, HBO began using the now-obsolete VideoCipher
system to encrypt their channels
. This met with much protest from owners of big-dish systems, most of which had no other option at the time for receiving such channels. Eventually HBO allowed dish owners to subscribe directly to their service, although at a price much higher ($12.95/month) than what cable subscribers were paying. This led to the 1986 attack on HBO's transponder on Galaxy 1
by Captain Midnight. One by one, all commercial channels followed HBO's lead and began encrypting their channels. Analogue encryption using VideoCipher and VideoCipher II could be defeated, and there was a black market for illegal descramblers. In the mid-1990s, channels began moving their broadcasts to digital TV transmission using DigiCipher scrambling and conditional access
.
In addition to encryption, DBS
services such as PrimeStar
had been reducing the popularity for BUDs since the early 1990s. Signals from DBS satellites (operating in the more recent Ku band
) are higher in power (due to improvements in the solar panels and energy efficiency of modern satellites) and therefore require much smaller dishes than C band, and the digital
signals now used require far less signal strength
at the receiver, resulting in a lower cost of entry. Each satellite also can carry up to 32 transponders in the Ku band, but only 24 in the C band, and several digital subchannel
s can be multiplex
ed (MCPC) or carried separately (SCPC) on a single transponder. General advancements in noise abatement have also had an effect. However, a consequence of the higher frequency used for DBS services is rain fade
where viewers lose signal during a heavy downpour. C-Band's immunity to rain fade
is one of the major reasons the BUD is still used as the preferred method for television broadcasters to distribute their signal.
areas, beyond the broadcast range of most local TV stations. The mountain
ous terrain
of West Virginia
, for example, makes reception of over-the-air television broadcast
s (especially in the higher UHF frequencies) very difficult. From the 1970s to the early 1990s DBS systems weren't available, and cable TV systems of the time only carried a few channels, resulting in a boom in sales of BUDs in the area, which led to the systems being termed the "West Virginia state flower". The term was regional, known mostly to those living in West Virginia and surrounding areas. Support for BUDs dried up when strong encryption
was introduced around 1994. Many long-disconnected BUDs still occupy their original spot. Due to the number of systems in existence, their lack of usefulness, and because many people consider them an eyesore, used BUDs can be purchased for very little money.
As of 2009, there are 23 C-band satellites and 38 Ku/Ka band satellites.
There are over 150 channels for people who want to receive subscription channels on a C-band dish via Motorola's 4DTV
equipment via two vendors Satellite Receivers Ltd (SRL) and Skyvision.
The dishes themselves can be modified to receive free-to-air
and DBS signals. The stock
LNBs fitted to typical BUDs will usually need to be replaced with one of a lower noise temperature to receive digital broadcasts. With a suitable replacement LNB (provided there is no warping of the reflector) a BUD can be used to receive free-to-air (FTA) and DBS
signals. Several companies market LNBs, LNBFs, and adaptor collars for big-dish systems. For receiving FTA signals the replacement should be capable of dual C/Ku reception with linear polarization
, for DBS it will need a high band Ku LNBF using circular polarization
. Older mesh dishes with perforations larger than 5mm are inefficient at Ku frequencies, because the smaller wavelength
s will pass through them. Solid fiberglass dishes usually contain metal mesh with large-diameter perforations as a reflector and are usually unsuitable for anything other than C band.
Large dishes have higher antenna gain
, which can be an advantage when used with DBS signals such as Dish Network
and DirecTV
, virtually eliminating rain fade
. Restored dishes fitted with block upconverter
s can be used to transmit signals as well. BUDs can still be seen at antenna farm
s for these reasons, so that video
and backhauls can be sent to and from the TV network with which a station is affiliate
d, without interruption due to inclement weather
. BUDs are also still useful for picking-up weak signals at the edge of a satellite's broadcast "footprint" — the area at which a particular satellite is aimed. For this reason, BUDs are helpful in places like Alaska
, or parts of the Caribbean
.
s similar to BUDs are still in production by companies such as Fortec Star
and Standard Antenna Manufacturing Inc.. New dishes differ in their construction and materials. New mesh dishes have much smaller perforations and solid dishes are now made with steel instead of fiberglass. New systems usually include a universal LNB which is switched electronically between horizontal and vertical polarization, obviating the need for a failure-prone polarotor. As a complete system they have a much lower noise temperature than old BUDs, and are generally better for digital Ku reception. The prices on these dishes have fallen dramatically since the first BUDs were produced from several thousand dollars to as little as $189 as of 2008. Typical uses for these systems include receiving free-to-air and subscription services.
As of 2010 SeaTel continues to dominate the market for stabilized TVRO systems and has according to the Comsys group a market share of 75%. Other established providers of stabilised satellite antennas are Intellian, KNS, Orbit and KVH.
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
to refer to the reception of satellite television
Satellite television
Satellite television is television programming delivered by the means of communications satellite and received by an outdoor antenna, usually a parabolic mirror generally referred to as a satellite dish, and as far as household usage is concerned, a satellite receiver either in the form of an...
from FSS
Fixed Service Satellite
Fixed Service Satellite , is the official classification for geostationary communications satellites used for broadcast feeds for television stations and radio stations and broadcast networks, as well as for telephony, telecommunications and data communications.FSS satellites have also been used...
-type satellites, generally on C-band analog; free-to-air
Free-to-air
Free-to-air describes television and radio services broadcast in clear form, allowing any person with the appropriate receiving equipment to receive the signal and view or listen to the content without requiring a subscription or one-off fee...
and unconnected to a commercial DBS
Direct broadcast satellite
Direct broadcast satellite is a term used to refer to satellite television broadcasts intended for home reception.A designation broader than DBS would be direct-to-home signals, or DTH. This has initially distinguished the transmissions directly intended for home viewers from cable television...
provider. TVRO systems rely on feeds being transmitted unencrypted and using open-standards, which heavily contrasts to DBS systems in the region.
The term is rarely used in recent times due to the general move towards pay television and subscription-based DBS services like DirecTV
DirecTV
DirecTV is an American direct broadcast satellite service provider and broadcaster based in El Segundo, California. Its satellite service, launched on June 17, 1994, transmits digital satellite television and audio to households in the United States, Latin America, and the Anglophone Caribbean. ...
, Dish Network
Dish Network
Dish Network Corporation is the second largest pay TV provider in the United States, providing direct broadcast satellite service—including satellite television, audio programming, and interactive television services—to 14.337 million commercial and residential customers in the United States. Dish...
, Bell TV, and Sky TV
Sky Digital (UK & Ireland)
Sky is the brand name for British Sky Broadcasting's digital satellite television and radio service, transmitted from SES Astra satellites located at 28.2° east and Eutelsat's Eurobird 1 satellite at 28.5°E. The service was originally launched as Sky Digital, distinguishing it from the original...
, although it is still sometimes used to refer to receiving digital TV "backhaul" feeds from FSS
Fixed Service Satellite
Fixed Service Satellite , is the official classification for geostationary communications satellites used for broadcast feeds for television stations and radio stations and broadcast networks, as well as for telephony, telecommunications and data communications.FSS satellites have also been used...
-type satellites.
TVRO was once the sole, and later the main means of consumer satellite reception in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
, until the mid-1990s and the arrival of services such as PrimeStar
PrimeStar
PrimeStar was a U.S. direct broadcast satellite broadcasting company formed in 1991 by a consortium of cable television system operators. PrimeStar was the first medium-powered DBS system in the United States but slowly declined in popularity with the arrival of DirecTV in 1994 and Dish Network in...
, USSB
United States Satellite Broadcasting
United States Satellite Broadcasting was a satellite television company that ran from 1981 to 1998. It was purchased by DirecTV in 1998.-History:...
, DirecTV
DirecTV
DirecTV is an American direct broadcast satellite service provider and broadcaster based in El Segundo, California. Its satellite service, launched on June 17, 1994, transmits digital satellite television and audio to households in the United States, Latin America, and the Anglophone Caribbean. ...
, and Dish Network
Dish Network
Dish Network Corporation is the second largest pay TV provider in the United States, providing direct broadcast satellite service—including satellite television, audio programming, and interactive television services—to 14.337 million commercial and residential customers in the United States. Dish...
. While these services are at least theoretically based on open standards (DVB-S
DVB-S
DVB-S is an abbreviation for Digital Video Broadcasting — Satellite; it is the original Digital Video Broadcasting forward error coding and demodulation standard for satellite television and dates from 1994, in its first release, while development lasted from 1993 to 1997...
, MPEG-2
MPEG-2
MPEG-2 is a standard for "the generic coding of moving pictures and associated audio information". It describes a combination of lossy video compression and lossy audio data compression methods which permit storage and transmission of movies using currently available storage media and transmission...
, MPEG-4
MPEG-4
MPEG-4 is a method of defining compression of audio and visual digital data. It was introduced in late 1998 and designated a standard for a group of audio and video coding formats and related technology agreed upon by the ISO/IEC Moving Picture Experts Group under the formal standard ISO/IEC...
), the majority of services are encrypted and require proprietary decoder hardware.
Reception of free-to-air satellite signals, generally Ku band
Ku band
The Kμ band is a portion of the electromagnetic spectrum in the microwave range of frequencies. This symbol refers to —in other words, the band directly below the K-band...
Digital Video Broadcasting, for home viewing is still common in Europe, India and Australia, although the TVRO nomenclature was never used there.
Free-to-air satellite signals are also very common in the People's Republic of China
People's Republic of China
China , officially the People's Republic of China , is the most populous country in the world, with over 1.3 billion citizens. Located in East Asia, the country covers approximately 9.6 million square kilometres...
, as many rural locations cannot receive cable television
Cable television
Cable television is a system of providing television programs to consumers via radio frequency signals transmitted to televisions through coaxial cables or digital light pulses through fixed optical fibers located on the subscriber's property, much like the over-the-air method used in traditional...
and solely rely on satellites to deliver television signals to individual homes.
Big ugly dish
Name
A name is a word or term used for identification. Names can identify a class or category of things, or a single thing, either uniquely, or within a given context. A personal name identifies a specific unique and identifiable individual person, and may or may not include a middle name...
for a TVRO satellite dish
Satellite dish
A satellite dish is a dish-shaped type of parabolic antenna designed to receive microwaves from communications satellites, which transmit data transmissions or broadcasts, such as satellite television.-Principle of operation:...
used to receive satellite
Satellite
In the context of spaceflight, a satellite is an object which has been placed into orbit by human endeavour. Such objects are sometimes called artificial satellites to distinguish them from natural satellites such as the Moon....
television
Television
Television is a telecommunication medium for transmitting and receiving moving images that can be monochrome or colored, with accompanying sound...
signals from FSS
Fixed Service Satellite
Fixed Service Satellite , is the official classification for geostationary communications satellites used for broadcast feeds for television stations and radio stations and broadcast networks, as well as for telephony, telecommunications and data communications.FSS satellites have also been used...
-type satellites on the microwave
Microwave
Microwaves, a subset of radio waves, have wavelengths ranging from as long as one meter to as short as one millimeter, or equivalently, with frequencies between 300 MHz and 300 GHz. This broad definition includes both UHF and EHF , and various sources use different boundaries...
C band
C band
The C band is a name given to certain portions of the electromagnetic spectrum, including wavelengths of microwaves that are used for long-distance radio telecommunications. The IEEE C-band - and its slight variations - contains frequency ranges that are used for many satellite communications...
. BUDs are usually 6½ to 12 feet or two to 3.5 meters in diameter
Diameter
In geometry, a diameter of a circle is any straight line segment that passes through the center of the circle and whose endpoints are on the circle. The diameters are the longest chords of the circle...
, and have been a source of much consternation (even local zoning
Zoning
Zoning is a device of land use planning used by local governments in most developed countries. The word is derived from the practice of designating permitted uses of land based on mapped zones which separate one set of land uses from another...
disputes) due to their perception as an eyesore
Eyesore
An eyesore is an unpleasant view. Its technical usage is as an alternative perspective to the notion of landmark. Common examples include dilapidated buildings, graffiti, litter, polluted areas and excessive commercial signage such as billboards. Some eyesores may be a matter of opinion such as...
. Neighborhoods with restrictive covenant
Restrictive covenant
A restrictive covenant is a type of real covenant, a legal obligation imposed in a deed by the seller upon the buyer of real estate to do or not to do something. Such restrictions frequently "run with the land" and are enforceable on subsequent buyers of the property...
s usually prohibit this size of dish, except where such restrictions are illegal.
History
BUDs were originally marketed in the late 1970s, with the earliest dishes being made of solid fiberglassFiberglass
Glass fiber is a material consisting of numerous extremely fine fibers of glass.Glassmakers throughout history have experimented with glass fibers, but mass manufacture of glass fiber was only made possible with the invention of finer machine tooling...
and later models being made of wire
Wire
A wire is a single, usually cylindrical, flexible strand or rod of metal. Wires are used to bear mechanical loads and to carry electricity and telecommunications signals. Wire is commonly formed by drawing the metal through a hole in a die or draw plate. Standard sizes are determined by various...
mesh
Mesh
Mesh consists of semi-permeable barrier made of connected strands of metal, fiber, or other flexible/ductile material. Mesh is similar to web or net in that it has many attached or woven strands.-Types of mesh:...
and solid steel
Steel
Steel is an alloy that consists mostly of iron and has a carbon content between 0.2% and 2.1% by weight, depending on the grade. Carbon is the most common alloying material for iron, but various other alloying elements are used, such as manganese, chromium, vanadium, and tungsten...
or aluminum. Fiberglass dishes are most commonly found on low rise commercial buildings, while the wire mesh counterparts are typically found on residential buildings. BUD systems of the time came at a high cost, usually several thousand dollars.
They work by receiving a low-power C-Band (3.7-4.2 GHz) frequency-modulated
Frequency modulation
In telecommunications and signal processing, frequency modulation conveys information over a carrier wave by varying its instantaneous frequency. This contrasts with amplitude modulation, in which the amplitude of the carrier is varied while its frequency remains constant...
analog television
Analog television
Analog television is the analog transmission that involves the broadcasting of encoded analog audio and analog video signal: one in which the message conveyed by the broadcast signal is a function of deliberate variations in the amplitude and/or frequency of the signal...
signal directly from the original distribution satellite — the same signal received by cable-company headend
Cable television headend
A cable television headend is a master facility for receiving television signals for processing and distribution over a cable television system. The headend facility is normally unstaffed and surrounded by some type of security fencing and is typically a building or large shed housing electronic...
s. Because analog channels took up an entire transponder
Transponder
In telecommunication, the term transponder has the following meanings:...
on the satellite, and each satellite had a fixed number of transponders, dishes were usually equipped with a polar mount
Polar mount
A polar mount is a movable mount for satellite dishes that allows the dish to be pointed at many geostationary satellites by slewing around one axis...
and actuator
Actuator
An actuator is a type of motor for moving or controlling a mechanism or system. It is operated by a source of energy, usually in the form of an electric current, hydraulic fluid pressure or pneumatic pressure, and converts that energy into some kind of motion. An actuator is the mechanism by which...
to sweep the dish across the horizon to receive channels from multiple satellites. Switching between horizontal and vertical polarization was accomplished by a small electric servo
Servomechanism
thumb|right|200px|Industrial servomotorThe grey/green cylinder is the [[Brush |brush-type]] [[DC motor]]. The black section at the bottom contains the [[Epicyclic gearing|planetary]] [[Reduction drive|reduction gear]], and the black object on top of the motor is the optical [[rotary encoder]] for...
motor which moved a probe inside the feedhorn throat at the command of the receiver (commonly called a "polarotor" setup). Higher-end receivers did this transparently, switching polarization and moving the dish automatically as the user changed channels.
Originally, all channels could be received in the clear
In the Clear
In the Clear is an album released by the band Ivy on March 1, 2005 on Nettwerk.When starting sessions for In The Clear, the band tried to strike a balance between the immediacy of their early recordings and the careful sonic detailing of their more recent work...
(ITC) and free of charge. In 1986, HBO began using the now-obsolete VideoCipher
Videocipher
VideoCipher is a brand name of analog scrambling and de-scrambling equipment for cable and satellite television invented primarily to keep consumer Television receive-only satellite equipment from receiving TV programing except on a subscription basis. It was invented in 1983 by Linkabit...
system to encrypt their channels
Television encryption
Television encryption, often referred to as "scrambling", is encryption used to control access to pay television services, usually cable or satellite television services.-History:...
. This met with much protest from owners of big-dish systems, most of which had no other option at the time for receiving such channels. Eventually HBO allowed dish owners to subscribe directly to their service, although at a price much higher ($12.95/month) than what cable subscribers were paying. This led to the 1986 attack on HBO's transponder on Galaxy 1
Galaxy 1
Galaxy 1 was the first in a line of communications satellites launched by Hughes Communications in 1983. It was the first satellite exclusively devoted to cable television, and carried many such services as HBO, Cinemax, The Movie Channel, Showtime, The Disney Channel, TBS, CNN, among some.In...
by Captain Midnight. One by one, all commercial channels followed HBO's lead and began encrypting their channels. Analogue encryption using VideoCipher and VideoCipher II could be defeated, and there was a black market for illegal descramblers. In the mid-1990s, channels began moving their broadcasts to digital TV transmission using DigiCipher scrambling and conditional access
Conditional access
Conditional Access is the protection of content by requiring certain criteria to be met before granting access to this content...
.
In addition to encryption, DBS
Direct broadcast satellite
Direct broadcast satellite is a term used to refer to satellite television broadcasts intended for home reception.A designation broader than DBS would be direct-to-home signals, or DTH. This has initially distinguished the transmissions directly intended for home viewers from cable television...
services such as PrimeStar
PrimeStar
PrimeStar was a U.S. direct broadcast satellite broadcasting company formed in 1991 by a consortium of cable television system operators. PrimeStar was the first medium-powered DBS system in the United States but slowly declined in popularity with the arrival of DirecTV in 1994 and Dish Network in...
had been reducing the popularity for BUDs since the early 1990s. Signals from DBS satellites (operating in the more recent Ku band
Ku band
The Kμ band is a portion of the electromagnetic spectrum in the microwave range of frequencies. This symbol refers to —in other words, the band directly below the K-band...
) are higher in power (due to improvements in the solar panels and energy efficiency of modern satellites) and therefore require much smaller dishes than C band, and the digital
Digital
A digital system is a data technology that uses discrete values. By contrast, non-digital systems use a continuous range of values to represent information...
signals now used require far less signal strength
Signal strength
In telecommunications, particularly in radio, signal strength refers to the magnitude of the electric field at a reference point that is a significant distance from the transmitting antenna. It may also be referred to as received signal level or field strength. Typically, it is expressed in...
at the receiver, resulting in a lower cost of entry. Each satellite also can carry up to 32 transponders in the Ku band, but only 24 in the C band, and several digital subchannel
Digital subchannel
In broadcasting, digital subchannels are a means to transmit more than one independent program at the same time from the same digital radio or digital television station on the same radio frequency channel. This is done by using data compression techniques to reduce the size of each individual...
s can be multiplex
Multiplex (TV)
A multiplex or mux is a group of TV channels that are mixed together for broadcast over a digital TV channel and separated out again by the receiver...
ed (MCPC) or carried separately (SCPC) on a single transponder. General advancements in noise abatement have also had an effect. However, a consequence of the higher frequency used for DBS services is rain fade
Rain fade
Rain fade refers primarily to the absorption of a microwave radio frequency signal by atmospheric rain, snow or ice, and losses are especially prevalent at frequencies above 11 GHz. It also refers to the degradation of a signal caused by the electromagnetic interference of the leading edge of a...
where viewers lose signal during a heavy downpour. C-Band's immunity to rain fade
Rain fade
Rain fade refers primarily to the absorption of a microwave radio frequency signal by atmospheric rain, snow or ice, and losses are especially prevalent at frequencies above 11 GHz. It also refers to the degradation of a signal caused by the electromagnetic interference of the leading edge of a...
is one of the major reasons the BUD is still used as the preferred method for television broadcasters to distribute their signal.
Popularity
BUDs were most popular in ruralRural
Rural areas or the country or countryside are areas that are not urbanized, though when large areas are described, country towns and smaller cities will be included. They have a low population density, and typically much of the land is devoted to agriculture...
areas, beyond the broadcast range of most local TV stations. The mountain
Mountain
Image:Himalaya_annotated.jpg|thumb|right|The Himalayan mountain range with Mount Everestrect 58 14 160 49 Chomo Lonzorect 200 28 335 52 Makalurect 378 24 566 45 Mount Everestrect 188 581 920 656 Tibetan Plateaurect 250 406 340 427 Rong River...
ous terrain
Terrain
Terrain, or land relief, is the vertical and horizontal dimension of land surface. When relief is described underwater, the term bathymetry is used...
of West Virginia
West Virginia
West Virginia is a state in the Appalachian and Southeastern regions of the United States, bordered by Virginia to the southeast, Kentucky to the southwest, Ohio to the northwest, Pennsylvania to the northeast and Maryland to the east...
, for example, makes reception of over-the-air television broadcast
Broadcast
Broadcast or Broadcasting may refer to:* Broadcasting, the transmission of audio and video signals* Broadcast, an individual television program or radio program* Broadcast , an English electronic music band...
s (especially in the higher UHF frequencies) very difficult. From the 1970s to the early 1990s DBS systems weren't available, and cable TV systems of the time only carried a few channels, resulting in a boom in sales of BUDs in the area, which led to the systems being termed the "West Virginia state flower". The term was regional, known mostly to those living in West Virginia and surrounding areas. Support for BUDs dried up when strong encryption
Encryption
In cryptography, encryption is the process of transforming information using an algorithm to make it unreadable to anyone except those possessing special knowledge, usually referred to as a key. The result of the process is encrypted information...
was introduced around 1994. Many long-disconnected BUDs still occupy their original spot. Due to the number of systems in existence, their lack of usefulness, and because many people consider them an eyesore, used BUDs can be purchased for very little money.
Current uses
The free analogue channels that BUDs were built to receive are mostly a memory.As of 2009, there are 23 C-band satellites and 38 Ku/Ka band satellites.
There are over 150 channels for people who want to receive subscription channels on a C-band dish via Motorola's 4DTV
4DTV
4DTV is the name of a Television receive-only consumer satellite television tuner technology manufactured by Motorola for use with large-diameter parabolic satellite dish antennas on the C and Ku frequency bands on multiple satellites...
equipment via two vendors Satellite Receivers Ltd (SRL) and Skyvision.
The dishes themselves can be modified to receive free-to-air
Free-to-air
Free-to-air describes television and radio services broadcast in clear form, allowing any person with the appropriate receiving equipment to receive the signal and view or listen to the content without requiring a subscription or one-off fee...
and DBS signals. The stock
Stock
The capital stock of a business entity represents the original capital paid into or invested in the business by its founders. It serves as a security for the creditors of a business since it cannot be withdrawn to the detriment of the creditors...
LNBs fitted to typical BUDs will usually need to be replaced with one of a lower noise temperature to receive digital broadcasts. With a suitable replacement LNB (provided there is no warping of the reflector) a BUD can be used to receive free-to-air (FTA) and DBS
Direct broadcast satellite
Direct broadcast satellite is a term used to refer to satellite television broadcasts intended for home reception.A designation broader than DBS would be direct-to-home signals, or DTH. This has initially distinguished the transmissions directly intended for home viewers from cable television...
signals. Several companies market LNBs, LNBFs, and adaptor collars for big-dish systems. For receiving FTA signals the replacement should be capable of dual C/Ku reception with linear polarization
Linear polarization
In electrodynamics, linear polarization or plane polarization of electromagnetic radiation is a confinement of the electric field vector or magnetic field vector to a given plane along the direction of propagation...
, for DBS it will need a high band Ku LNBF using circular polarization
Circular polarization
In electrodynamics, circular polarization of an electromagnetic wave is a polarization in which the electric field of the passing wave does not change strength but only changes direction in a rotary type manner....
. Older mesh dishes with perforations larger than 5mm are inefficient at Ku frequencies, because the smaller wavelength
Wavelength
In physics, the wavelength of a sinusoidal wave is the spatial period of the wave—the distance over which the wave's shape repeats.It is usually determined by considering the distance between consecutive corresponding points of the same phase, such as crests, troughs, or zero crossings, and is a...
s will pass through them. Solid fiberglass dishes usually contain metal mesh with large-diameter perforations as a reflector and are usually unsuitable for anything other than C band.
Large dishes have higher antenna gain
Antenna gain
In electromagnetics, an antenna's power gain or simply gain is a key performance figure which combines the antenna's directivity and electrical efficiency. As a transmitting antenna, the figure describes how well the antenna converts input power into radio waves headed in a specified direction...
, which can be an advantage when used with DBS signals such as Dish Network
Dish Network
Dish Network Corporation is the second largest pay TV provider in the United States, providing direct broadcast satellite service—including satellite television, audio programming, and interactive television services—to 14.337 million commercial and residential customers in the United States. Dish...
and DirecTV
DirecTV
DirecTV is an American direct broadcast satellite service provider and broadcaster based in El Segundo, California. Its satellite service, launched on June 17, 1994, transmits digital satellite television and audio to households in the United States, Latin America, and the Anglophone Caribbean. ...
, virtually eliminating rain fade
Rain fade
Rain fade refers primarily to the absorption of a microwave radio frequency signal by atmospheric rain, snow or ice, and losses are especially prevalent at frequencies above 11 GHz. It also refers to the degradation of a signal caused by the electromagnetic interference of the leading edge of a...
. Restored dishes fitted with block upconverter
Block upconverter
A block upconverter is used in the transmission of satellite signals. It converts a band of frequencies from a lower frequency to a higher frequency. Modern BUCs convert from the L band to Ku band, C band and Ka band...
s can be used to transmit signals as well. BUDs can still be seen at antenna farm
Antenna farm
Antenna farm or satellite dish farm or just dish farm are terms used to describe an area dedicated to television or radio telecommunications transmitting or receiving antenna equipment, such as C, Ku or Ka band satellite dish antennas, UHF/VHF/AM/FM transmitter towers or mobile cell towers.In...
s for these reasons, so that video
Video
Video is the technology of electronically capturing, recording, processing, storing, transmitting, and reconstructing a sequence of still images representing scenes in motion.- History :...
and backhauls can be sent to and from the TV network with which a station is affiliate
Affiliate
An affiliate is a commercial entity with a relationship with a peer or a larger entity.- Corporate structure :A corporation may be referred to as an affiliate of another when it is related to it but not strictly controlled by it, as with a subsidiary relationship, or when it is desired to avoid...
d, without interruption due to inclement weather
Weather
Weather is the state of the atmosphere, to the degree that it is hot or cold, wet or dry, calm or stormy, clear or cloudy. Most weather phenomena occur in the troposphere, just below the stratosphere. Weather refers, generally, to day-to-day temperature and precipitation activity, whereas climate...
. BUDs are also still useful for picking-up weak signals at the edge of a satellite's broadcast "footprint" — the area at which a particular satellite is aimed. For this reason, BUDs are helpful in places like Alaska
Alaska
Alaska is the largest state in the United States by area. It is situated in the northwest extremity of the North American continent, with Canada to the east, the Arctic Ocean to the north, and the Pacific Ocean to the west and south, with Russia further west across the Bering Strait...
, or parts of the Caribbean
Caribbean
The Caribbean is a crescent-shaped group of islands more than 2,000 miles long separating the Gulf of Mexico and the Caribbean Sea, to the west and south, from the Atlantic Ocean, to the east and north...
.
Modern equivalents
Large parabolic antennaParabolic antenna
A parabolic antenna is an antenna that uses a parabolic reflector, a curved surface with the cross-sectional shape of a parabola, to direct the radio waves. The most common form is shaped like a dish and is popularly called a dish antenna or parabolic dish...
s similar to BUDs are still in production by companies such as Fortec Star
Fortec Star
Fortec Star is an International Satellite DVB receivers and Satellite equipment manufacturer headquartered in Mississauga, Canada.- Fortec Star Satellite Receivers :...
and Standard Antenna Manufacturing Inc.. New dishes differ in their construction and materials. New mesh dishes have much smaller perforations and solid dishes are now made with steel instead of fiberglass. New systems usually include a universal LNB which is switched electronically between horizontal and vertical polarization, obviating the need for a failure-prone polarotor. As a complete system they have a much lower noise temperature than old BUDs, and are generally better for digital Ku reception. The prices on these dishes have fallen dramatically since the first BUDs were produced from several thousand dollars to as little as $189 as of 2008. Typical uses for these systems include receiving free-to-air and subscription services.
TVRO on Ships
The term TVRO has been in use on ships since it was introduced in the 1980s. One early provider of equipment was SeaTel with its first generation of stabilized satellite antennas that was launched in 1985, the TV-at-Sea 8885 system. Until this time ships had not been able to receive TV signals from satellites due to their rocking motion rendering reception impossible. The SeaTel antenna however was stabilized using electrically driven gyroscopes and thus made it possible to point to the satellite accurately enough, that is to within 2 degrees, in order to receive a signal. The successful implementation of stabilised TVRO systems on ships immediately led to the development of maritime VSAT systems. The second generation of SeaTel TVRO systems came in 1994 and was the 2494 antenna, which got its gyro signal from the ship rather than its own gyros, improving accuracy and reducing maintenance.As of 2010 SeaTel continues to dominate the market for stabilized TVRO systems and has according to the Comsys group a market share of 75%. Other established providers of stabilised satellite antennas are Intellian, KNS, Orbit and KVH.
External links
- rec.video.satellite.tvro FAQ
- Broadcast Engineering (magazine) - Satellite TVRO
- Part 1, Part 2, Part 3, Part 4
- C/Ku Band Satellite Systems - Tuning, Tracking...
- How to set up and align a BUD
- US satellite TV subscription provider for BUDs
- Canadian satellite TV subscription provider for BUDs