Distribution Network: Difference between revisions
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== Original Network == | == Original Network == | ||
When the University was built during the late 60s and early 70s, a closed circuit system of | When the University was built during the late 60s and early 70s, a closed circuit system of Audio Visual (AV) distribution was installed. The system allowed up to 4 channels to be conveyed around campus on a multipair pair cable, with each channel dedicated to a separate pair. An equipment room LTC (adjacent to Central Hall) acted as the transmission hub. For transmission, the video was modulated up to {{unsure|4.5}} MHz and the audio (at baseband) amplified at to an amplitude of {{unsure|100V}}. The transmission equipment and televisions were supplied by {{unsure|Rediffusion Vision}}. This method of cable based AV distribution was used in a number of towns in the UK, however it had reached the end of it's technological lifetime by the end of the 1980's. The system installed at the University of York was originally black and white and was upgraded to colour in the 1980s. | ||
<gallery> | <gallery> | ||
Image:19951213_LTC_rediffusion-racks.jpg|Rediffusion racks in LTC | Image:19951213_LTC_rediffusion-racks.jpg|Rediffusion racks in LTC | ||
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Image:19951213_LTC_distrubution-modulators.jpg|Video modulators in LTC | Image:19951213_LTC_distrubution-modulators.jpg|Video modulators in LTC | ||
</gallery> | </gallery> | ||
Installed alongside the distribution network was an AV contribution network. Located somewhere within most colleges was an AV rack. This was fed from a collection of contribution points located in seminar or lecture rooms in the college using coax for video and twisted pair for audio. Within the rack, the video could be patched in to a video line driver transmitter which was linked via twisted pair to a corresponding receiver over in LTC. The audio was directly patched as this was already balanced line. Wentworth was the last of the original 6 colleges to be built and no system of AV contribution was installed, presumably as a cost saving measure. | |||
The contribution/distribution system was quite advanced in it's day since it would have been possible to do point to multi-point lectures and video conference across campus. However, it is not known if it every was ever utilised beyond retransmission of BBC1/BBC2/ITV and contribution/distribution of YSTV. | |||
The passing of the years had taken its toll on the system. By 1994, various colleges/buildings had been remodelled, leading to removal of the AV racks or cutting of contribution/distribution cables. At the time YSTV moved into [[G/046]], the contribution cable from Goodricke back to LTC had suffered a break. This lead to the contribution point in [[P/X/002]] being pressed back into service. From here it fed back to the AV rack in [[P/S/016]] before being sent to LTC. At the time, YSTV could be seen in Derwent, Langwith, Alcuin, Vanbrugh and Goodricke. Wentworth distribution had been lost sometime between 1993-94. The distribution system suffered from having to use televisions that could receive the Rediffusion signal. This made replacing the teles difficult, since Rediffusion had pretty much dissapeared and the transmission system was technologically obsolete. The proximity of the Goodricke snack bar to [[G/046]], allowed audio and video to be fed at baseband to a normal television via a SCART socket. The remaining televisions soldiered on, and when required were repaired by using parts from any spares that could canniballised from the spares from the garage in Wentworth. Despite best efforts, picture quality was suffering, colour would turn to black and white and then back or various interference patterns could be seen on the screen. | |||
== Vanbrugh Upgrade == | == Vanbrugh Upgrade == | ||
== Beyond Vanbrugh == | == Beyond Vanbrugh == | ||
Revision as of 18:03, 18 May 2007
Original Network
When the University was built during the late 60s and early 70s, a closed circuit system of Audio Visual (AV) distribution was installed. The system allowed up to 4 channels to be conveyed around campus on a multipair pair cable, with each channel dedicated to a separate pair. An equipment room LTC (adjacent to Central Hall) acted as the transmission hub. For transmission, the video was modulated up to 4.5Unverified or incomplete information MHz and the audio (at baseband) amplified at to an amplitude of 100VUnverified or incomplete information. The transmission equipment and televisions were supplied by Rediffusion VisionUnverified or incomplete information. This method of cable based AV distribution was used in a number of towns in the UK, however it had reached the end of it's technological lifetime by the end of the 1980's. The system installed at the University of York was originally black and white and was upgraded to colour in the 1980s.
Rediffusion racks in LTC
Cable entry and exit in LTC
Video modulators in LTC
Installed alongside the distribution network was an AV contribution network. Located somewhere within most colleges was an AV rack. This was fed from a collection of contribution points located in seminar or lecture rooms in the college using coax for video and twisted pair for audio. Within the rack, the video could be patched in to a video line driver transmitter which was linked via twisted pair to a corresponding receiver over in LTC. The audio was directly patched as this was already balanced line. Wentworth was the last of the original 6 colleges to be built and no system of AV contribution was installed, presumably as a cost saving measure.
The contribution/distribution system was quite advanced in it's day since it would have been possible to do point to multi-point lectures and video conference across campus. However, it is not known if it every was ever utilised beyond retransmission of BBC1/BBC2/ITV and contribution/distribution of YSTV.
The passing of the years had taken its toll on the system. By 1994, various colleges/buildings had been remodelled, leading to removal of the AV racks or cutting of contribution/distribution cables. At the time YSTV moved into G/046, the contribution cable from Goodricke back to LTC had suffered a break. This lead to the contribution point in P/X/002 being pressed back into service. From here it fed back to the AV rack in P/S/016 before being sent to LTC. At the time, YSTV could be seen in Derwent, Langwith, Alcuin, Vanbrugh and Goodricke. Wentworth distribution had been lost sometime between 1993-94. The distribution system suffered from having to use televisions that could receive the Rediffusion signal. This made replacing the teles difficult, since Rediffusion had pretty much dissapeared and the transmission system was technologically obsolete. The proximity of the Goodricke snack bar to G/046, allowed audio and video to be fed at baseband to a normal television via a SCART socket. The remaining televisions soldiered on, and when required were repaired by using parts from any spares that could canniballised from the spares from the garage in Wentworth. Despite best efforts, picture quality was suffering, colour would turn to black and white and then back or various interference patterns could be seen on the screen.