Backhaul
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- This article refers to present TV usage, mainly in the USA. In the UK backhaul often means the optical fibre connection from the DSL equipment (DSLAM etc) in a telephone exchange back to the core network). Backhaul is also a term used in the freight industry to refer to freight carried by a trucker to return to his home with a loaded truck, rather than an empty one (as opposed to headhaul, the outgoing freight.)
In the context of broadcast television, backhaul refers to program content that is transmitted to a television station or receiving entity where it will be integrated into a finished show. The term is independent of the medium being used to send the backhaul, but satellite transmission is very common.
Reporters' live shots, sporting events and network programming are all examples of television content that is backhauled to a station before being made available to the public through that station. Cable TV channels (ESPN, HBO, etc.) are also backhauled to cable head ends before making their way to the consumer.
There exists a dedicated group of enthusiasts who use TVRO (TV Receive Only) gear such as (as they call them) big ugly dishes or BUDs to peek in on backhaul signals that are available on any of the dozens of communications satellites that are visible from almost any point on Earth. In its early days, their hobby was strengthened by the fact that most backhaul was analog and "in the clear" (unencrypted) which made for a vast smorgasbord of free television available for the technically inclined amateur. In recent years, full-time content and cable channels have added encryption and occasional signals are steadily becoming digital, which has had a deleterious effect on the hobby.
Some digital signals remain freely accessible (sometimes using Ku band dishes as small as one metre) under the international DVB standard or the US Motorola-proprietary Digicypher system. The small dishes may either be fixed (much like DBS antennas), positioned using a rotor (usually DiSEqC-standard) or may be toroidal in design (twin toroidal reflectors focus the incoming signal as a line, not a point, so that multiple LNBs may receive signal from multiple satellites). A blind-search receiver is often used to try every possible combination of frequency and bitrate to search for backhaul signals on individual communication satellites.
The 1992 documentary Feed (see links, below) was compiled almost entirely using unedited backhaul from campaign coverage by local and network television. A similar documentary about the 1992 U.S. presidential election named Spin was made in the same way in 1995.
External links
- Google Groups: rec.video.satellite.tvro newsgroup (http://groups.google.com/groups?hl=en&lr=&ie=UTF-8&group=rec.video.satellite.tvro)
- LyngSat (http://www.lyngsat.com/)
- http://www.multilnbdish.com/
- http://www.pansat.com/
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