Rediffusion Wired Vision System

Rediffusion commenced the distribution of audio signals shortly after the BBC began regular radio broadcasts in the UK. Read More
The programmes were received at a wireless receiving station and sent down wires straight to the customer's home where all that was needed was a volume control housed in the loudspeaker.
The system proved a cost effective alternative to owning an expensive wireless set and subscribers were connected in many UK towns and the system was also duplicated in a number of overseas territories including: Malta, Singapore, Hong Kong, Malaya, Barbados and Montreal.
In order to supply the service to so many homes on a particular cable route, large audio amplifiers had to be installed to boost the signal to give sufficient volume to each individual subscriber.
By 1945 the British Post Office had licensed over 200 providers of Radio Relay Services. Read More

In 1936 the BBC commenced high definition television broadcasting from Alexander Palace in London but with the outbreak of WWll this service was suspended. The distribution of BBC radio continued through this period and proved an invaluable service to many both and home and abroad.

To coincide with the resumption of TV broadcasts by the BBC after the war in 1946, Rediffusion carried out some experiments with vision signals along coaxial cables using the "off air" 45mhz carrier frequency but because of signal attenuation and severe "ghosting" the trial was abandoned.
Further development continued and the HF. system was adopted using a 9.72MHz carrier with upper sideband video modulation , this system was given the name TDUK1. See Rediffusion Research

With the arrival of a second television channel ( ITV ) in 1955, a new distribution service was designed known as TDUK2 in order to carry the two TV channels now available. This was a Tete-Beche signal. One program was transmitted at 4.95MHz upper sideband and the second was transmitted at 8.45MHz lower sideband.
By 1963 further development of the wired system took place to accommodate the proposal for 625 line UHF television transmissions which started in 1965 with the BBC2 channel. The TD.80 system for distributing a 625-line channel alongside TDUK.2 and TDUK.3 was introduced. Read More

Rediffusion developed a "world first" when in 1973 it demonstrated a TV signal sent over 1 mile by means of a Fibre Optic Cable running in parallel with the main vision trunk route at Hastings in Kent. The demonstration was a success and comparison could be made between a signal sent over copper or fibre optics.

Rediffusion Engineering developed a new concept called the Dial-a-Program system which was the world’s first and largest random access closed circuit installation in terms of programme capacity. 1979 saw the commission of the 72-channel programme switching centre, located in the Television Centre building in Johannesburg, South Africa, which handled 48 vision and 24 radio sound sources.

With the approach of the 1980's It was realised that many other programmes would shortly be available and a new multichannel transmission system was designed. This was known as System 8, it used 5 coaxial cables each carrying 6 TV channels at VHF. Trials were very successful but by the mid 80's the system was abandoned after the Rediffusion businesses were sold into new ownership.

The Rediffusion Wired Vision Network was a very sophisticated and complex system in its time. The planning, development and engineering required an enormous amount of technical expertise both nationally and internationally.
Though it is not possible to deal with all of the aspects of Wired Vision within this web page, much information on the subject is covered on the subsequent pages of this website: