Distribution Network: Difference between revisions

From YSTV History Wiki
Jump to navigation Jump to search
(Text shuffle to remove duplication, needs a bit more editing.)
(Chopped duplication)
Line 2: Line 2:
The Distribution Network was for the first 37 years of YSTV's history the only way to watch our [[YSTV Productions|programmes]] before the availability of content via [[Watch Online|our website]]. It mirrors the [[Contribution Network]] used to get video from around campus back to YSTV's studios for broadcasting [[Events Coverage|major events]] around campus.
The Distribution Network was for the first 37 years of YSTV's history the only way to watch our [[YSTV Productions|programmes]] before the availability of content via [[Watch Online|our website]]. It mirrors the [[Contribution Network]] used to get video from around campus back to YSTV's studios for broadcasting [[Events Coverage|major events]] around campus.


The [[original broadcast network|Original Network]] was installed as the university was being built in the 60's.
The [[Original Broadcast Network|original network]] was installed as the university was being built in the 60's.


== Early 90's system ageing ==
== Early 90's system ageing ==
The passing of time 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 the Language Teaching Centre (aka LTC) had suffered a break due to the same building work that had lead to the society's eviction from [[P/X/002]]. This lead to the contribution point in [[P/X/002]] being pressed back into service. Cables were trailed over the roof of Goodricke college from the new studio to the physics building. From here it fed back to the AV rack in [[P/S/016]] before being sent on to LTC.  
The passing of time 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 the Language Teaching Centre (aka LTC) had suffered a break due to the same building work that had lead to the society's eviction from [[P/X/002]]. This lead to the contribution point in [[P/X/002]] being pressed back into service. Cables were trailed over the roof of Goodricke college from the new studio to the physics building. From here it fed back to the AV rack in [[P/S/016]] before being sent on to LTC.  


At this time YSTV could be seen in Derwent, Langwith, Alcuin, Vanbrugh and Goodricke (due to the proximity of the Goodricke snack bar and JCR to [[G/046]] these were fed at baseband into a standard SCART television). Wentworth distribution had been lost sometime between 1993-94.  
At this time YSTV could be seen in Derwent, Langwith, Alcuin, Central hall, Vanbrugh and Goodricke (due to the proximity of the Goodricke snack bar and JCR to [[G/046]] these were fed at baseband into a standard SCART television). Wentworth distribution had been lost sometime between 1993-94.  


The remaining televisions soldiered on, and when required were repaired by using parts from any spares that could cannibalised 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.
Failed televisions were repaired by using parts from any spares that could cannibalised from the spares from the garage in Wentworth, as the were no longer in production. 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.


An attempt was made to convince the University to invest in installing a new system of coaxial cable (for unbalanced base-band video) and balanced audio around the campus, but the carrot of allowing them to use it during the conference season was unappealing, and nothing happened.
An attempt was made to convince the University to invest in installing a new system of coaxial cable (for unbalanced base-band video) and balanced audio around the campus, but the carrot of allowing them to use it during the conference season was unappealing, and nothing happened.


== End of Rediffusion system ==
During the summer holidays of 1995, [[Owain Davies]] visited the station and stumbled across a flyer for video balanced line driver and receiver chips which looked ideally suited as it could send pictures over low cost twisted pair cable, bringing the possibility of a YSTV funded replacement network into reach. [[Vanbrugh Upgrade|Vanbrugh college]] was used to test out the devices.
During the summer holidays of 1995, [[Owain Davies]] visited the station and stumbled across a flyer from Maxim highlighting their MAX435/MAX436 video balanced line drivers and receivers. The example circuit diagram seemed a remarkable simple solution, just one IC for transmitter and one for the receiver. Owain had found in LTC the composite output from the contribution feed from Physics. The picture was in good condition, meaning the interference problems were occurring on the distribution side of the network only.


This lead to a plan to replace all the modulation equipment from the Rediffusion system with base-band video senders and receivers using the Maxim ICs, driving over the old contribution network cables to distribute video to the vent rooms, and then over the unbalanced video cables to the TVs themselves.
== Two kilometres of twisted pair ==
A budget surplus in 1997 left enough money in the society bank account at the end of year to buy a new set of identical ex-rental stereo televisions and two kilometres of cable - enough to rewire all colleges on campus.


This was implemented as a test in [[Vanbrugh Upgrade|Vanbrugh]] by Owain Davies, feeding the three TVs there, and worked very well. The problem of getting cables run from the vent rooms to the TVs was significant however, as it required cables to be run above ceilings and so on.
During the summer holidays of 1998 newly appointed Network Engineer [[Rob Sprowson]] convinced YSTV that it was time to replace the Rediffusion network, to install an entirely [[New Broadcast Network|new network]].
 
== Two kilometres of twisted pair ==
Given that this would be needed for almost all the colleges, [[Rob Sprowson]] opted to do the whole job, and run new cable from LTC to the TV locations. The receivers could then be installed near the TVs, and the contribution cables (which anyway did not run to Langwith or Derwent) left alone. This was implemented using 3-pair screened cable, providing for stereo audio and balanced video to all the available or proposed TV positions.


Despite the availability of content online it remains a valuable means of raising the society's profile on campus and generating interest in our output, the [[current broadcast network|Current Status]] is basically the 1998 layout minus sections lost to new building works, with some new links installed and a few of the TVs relocated.
Despite the availability of content online it remains a valuable means of raising the society's profile on campus and generating interest in our output, the [[Current Broadcast Network|status now]] is basically the 1998 layout minus sections lost to new building works, with some new links installed and a few of the TVs relocated.

Revision as of 11:09, 18 November 2007

Background

The Distribution Network was for the first 37 years of YSTV's history the only way to watch our programmes before the availability of content via our website. It mirrors the Contribution Network used to get video from around campus back to YSTV's studios for broadcasting major events around campus.

The original network was installed as the university was being built in the 60's.

Early 90's system ageing

The passing of time 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 the Language Teaching Centre (aka LTC) had suffered a break due to the same building work that had lead to the society's eviction from P/X/002. This lead to the contribution point in P/X/002 being pressed back into service. Cables were trailed over the roof of Goodricke college from the new studio to the physics building. From here it fed back to the AV rack in P/S/016 before being sent on to LTC.

At this time YSTV could be seen in Derwent, Langwith, Alcuin, Central hall, Vanbrugh and Goodricke (due to the proximity of the Goodricke snack bar and JCR to G/046 these were fed at baseband into a standard SCART television). Wentworth distribution had been lost sometime between 1993-94.

Failed televisions were repaired by using parts from any spares that could cannibalised from the spares from the garage in Wentworth, as the were no longer in production. 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.

An attempt was made to convince the University to invest in installing a new system of coaxial cable (for unbalanced base-band video) and balanced audio around the campus, but the carrot of allowing them to use it during the conference season was unappealing, and nothing happened.

During the summer holidays of 1995, Owain Davies visited the station and stumbled across a flyer for video balanced line driver and receiver chips which looked ideally suited as it could send pictures over low cost twisted pair cable, bringing the possibility of a YSTV funded replacement network into reach. Vanbrugh college was used to test out the devices.

Two kilometres of twisted pair

A budget surplus in 1997 left enough money in the society bank account at the end of year to buy a new set of identical ex-rental stereo televisions and two kilometres of cable - enough to rewire all colleges on campus.

During the summer holidays of 1998 newly appointed Network Engineer Rob Sprowson convinced YSTV that it was time to replace the Rediffusion network, to install an entirely new network.

Despite the availability of content online it remains a valuable means of raising the society's profile on campus and generating interest in our output, the status now is basically the 1998 layout minus sections lost to new building works, with some new links installed and a few of the TVs relocated.