25 September 2020 tbs.pm/71063

The main entrance to Television Centre

DEVELOPMENT OF THE BBC’s TELEVISION SERVICE

From the BBC Handbook for 1961

The BBC’s Television Service is at present within reach of approximately 98.8 per cent of the population of the United Kingdom. There are still some sparsely populated parts of the country which are not at present served by television, and it is one of the objects of the BBC to extend television coverage as far as possible into these areas. Plans are in ha.nd for this purpose and also to improve reception in areas where it is not at present wholly satisfactory.

When the BBC set out after the war to plan a national television service with coverage over the whole country, only the five channels in Band I were available. The BBC had hoped that some channels in Band III would also be allocated. As this hope was not fulfilled, all the twenty-three stations now operating have had to be accommodated in Band I. Mutual interference between BBC stations sharing the same channel is a real problem. To this is added the fact that television broadcasting in Band I is liable to interference caused by ionospheric and tropospheric propagation from other stations. This reduces the coverage at certain times below the figure quoted above. The BBC has adopted several technical artifices in an endeavour to exploit to the full the limited number of channels available in Band I.

The national network was built up rapidly. The five high-power stations were built and in operation by 1952, and gave a service to 81 per cent of the population. These stations were supplemented by medium-power and low-power transmitters to the present total number of twenty-three transmitting stations. Intolerable interference with the reception of existing stations would have been created if further high-power stations had been added to the five already in operation. Plans were therefore prepared for the building of a large number of low-power ‘satellite’ stations in order to complete the coverage as nearly as possible. Because of their short range a number of these stations can be operated in Band I without causing mutual interference. The Postmaster General’s approval was sought and obtained for the building of twenty-five satellite stations. They will bring the service to an additional 300,000 people and improve reception for approximately 1,500,000 who already have a service but not without interference. A special type of low-power equipment has been designed by the BBC for use at unattended satellite stations. This equipment, known as a ‘translator’, receives the television signals from an existing main station and re-transmits them on a different channel for local viewers.

The BBC’s television programmes do not all come from London. Many are originated in the BBC’s studios in Scotland, Wales, Northern Ireland, and in the English regions. Many of these programmes are broadcast over the whole network; others are intended only for viewers within the particular region. These are considerations which are taken into account in the siting of the main and satellite transmitting stations and in planning the routes by which the programmes are conveyed to them.

An aerial view of Television Centre

television studios Until 1950, BBC television operated under the handicap of having only the two small studios at Alexandra Palace with which the service was started in 1936. Even then a search was being made for a site on which larger studios could be built. This search was resumed after the war, and in 1949 a suitable site was found in Wood Lane, Shepherds Bush, in West London. Construction work on the new Television Centre which has been built on this site began in 1951. Meanwhile it was essential to find further studio accommodation for the rapidly expanding service, and at the beginning of 1950 the BBC bought a group of buildings at Shepherds Bush, known as the Lime Grove Studios, which had been used for film production. These studios were converted as rapidly as possible for television purposes and were brought into service progressively from 1950. In 1953 the old Shepherds Bush Empire was acquired mainly for the production of light entertainment shows requiring a studio audience. The extension of the hours of transmission made it essential to obtain still further studio space for immediate use, and this was met by the acquisition of the Riverside Film Studios at Hammersmith in 1956. The numbers and types of programmes contributed by the regions to the national network, in addition to programmes transmitted for reception only in the region itself, made it necessary to provide main regional studios as well as smaller interview studios which could be used for programmes such as news, talks, and interviews. As suitable premises were found and acquired in the main centres, temporary arrangements were made to use them on a ‘drive-in’ basis in conjunction with the region’s mobile outside broadcast unit until it was possible to install permanent equipment. Main and interview studios have now been permanently equipped in Birmingham, Manchester, Bristol, Cardiff, Glasgow, and Belfast; interview studios have also been set up in Newcastle, Norwich, and Southampton.

In London one of the two original studios at Alexandra Palace is now used for the news service, and interview studios have been equipped at All Souls Hall adjacent to Broadcasting House, at St. Stephen’s Hall (near the House of Commons), and at London Airport. St. Stephen’s Hall is an unattended studio in which the equipment is switched on as required from Alexandra Palace. All Souls Hall is equipped with a remotely-controlled camera of BBC design where the various camera operations (pan, tilt, focus, iris, and zoom) can be controlled from the News Centre at Alexandra Palace some six miles away.

The Television Centre is now the headquarters of the BBC Television Service; it is the controlling centre of the television network and contains the necessary offices for the direction, administrative, and engineering staff. The first of the buildings, the scenery block, was completed in 1953 and was immediately brought into use for the construction and storage of scenery and properties required at the Lime Grove and Riverside Studios and the Television Theatre. The restaurant block was built next and was used from 1955 to provide much needed rehearsal space and for offices. By June 1960 it had been converted to its normal use and can provide meals for 750 people at each of three successive sittings. The main block will include seven studios, of which four are being equipped in the first instance. These are the first studios to be designed and built expressly for the production of television programmes; all other BBC studios in London and the regions have been adaptations of existing buildings. The first of the new studios, Studio 3, was brought into service on 29 June 1960. Others will follow at intervals of a few months until the first group of four studios and two presentation studios are completed.

Television Centre Presentation Control Room – this desk is the focal point of production control during the transmission of the programmes

the recording of television programmes For various reasons it is necessary to record certain television programmes for subsequent reproduction; BBC engineers were working on this problem in the very early days of television. All the early attempts at recording were based on the principle of using a film camera to photograph the picture on a television monitor screen using either 16-mm or 35-mm film. A major difficulty encountered was that, with the normal type of film camera, the time required to pull down the film from one frame to the next is considerably longer than the interval between the presentation of successive television pictures on the monitor screen. In 1949, BBC engineers converted a continuous-motion film-projector mechanism (the Mechau) for use in conjunction with a film camera. This system was succeeded in 1953 by one (the suppressed-field system) which recorded only half the information in the television picture, but allowed ample time for the pull down of the film between pictures. This was followed in 1957 by yet another development, known as ‘the stored field system’, in which the equipment was modified so that it could record all the picture information. This equipment is still in use and can produce recordings of very high quality.

More recently still, in 1959, the BBC developed in conjunction with the manufacturers new equipment for recording television pictures on 35-mm film. In this equipment the time taken to pull down the film between successive frames has been greatly reduced, and an ingenious development, for which BBC engineers were also responsible, enables the whole of the picture information to be recorded. As a result of this development together with the use of improved film stock and new processing techniques, the quality of the pictures recorded by this system is remarkably good, and has elicited much favourable comment from abroad when the resulting film recordings have been transmitted there. Film telerecordings have the great advantage that they can be freely interchanged between countries and transmitted without difficulty by television systems having different technical standards.

Meanwhile, in this country and elsewhere, notably in the United States, the possibility of recording television signals on magnetic tape, in a manner analogous to the recording of sound programmes, was being investigated. In 1958 the BBC produced equipment capable of recording television signals on magnetic tape, known as V.E.R.A. (Vision Electronic Recording Apparatus), which was publicly demonstrated in an advanced experimental stage. By this time magnetic tape recording equipment operating on a different principle had been brought into service in the United States, and this videotape equipment, as it is called, is now used by the BBC. In addition to giving excellent picture quality, it has the advantage that similar equipment is used in many other countries, and this facilitates the exchange of recorded programmes. Videotape recordings have the advantage over film in that they can be replayed immediately, without any processing. Unfortunately, programmes recorded on videotape using the standards, i.e. the number of lines and the number of pictures reproduced each second, of the system in use in the originating country, cannot be reproduced on similar equipment in countries which use different standards. The BBC has, therefore, designed ‘Standards Converters’, which enable its programmes to be recorded on videotape at the North American 525-line standard or at the 625-line standard used on the Continent.

BBC cameras bring another ‘first’ to the television screens of Britain with the televising of the Grand National on 26 March 1960

A BBC sound radio mobile transmitter and Roving Eye Camera cover the Lincolnshire Handicap – from ‘This is the BBC’ which won the British Academy award for the Best Specialist Film of 1959

television cameras The BBC has worked in close cooperation with the manufacturers over the development of television cameras. Different types have been used as the service developed in order to gain experience of their merits and disadvantages. Emitron cameras were in use in studios up to 1950. An improved equipment, known as C.P.S. Emitron, was then brought into use, and later another type, the Photicon, was installed at Lime Grove. In 1953 Image Orthicon cameras were brought into use for the first time in studios at Lime Grove. These cameras, because of their high sensitivity, had been used to a large extent in outside broadcasts, where widely different conditions of lighting are encountered. For studio use the 3-inch pick-up tubes used in these cameras resulted in certain defects in picture quality, and in 1955 the BBC pioneered the use of the 4½-inch English Electric Image Orthicon tube. The 4½-inch camera and its associated control equipment have been brought to a very high degree of development by the manufacturers in co-operation with BBC engineers, and is to be standardized for studio use at the new Television Centre. It is also now used in the majority of the BBC’s outside broadcasting units.

In 1953 the BBC first used experimentally a photo-conductive Vidicon camera tube for an outside broadcast. These cameras are at present more widely used in telecine equipment and for industrial television, and they have certain limitations in picture quality for broadcasting purposes. There are, however, times when their small size and stability in operation can be used to advantage, for example, in the unattended studios in London at St. Stephen’s Hall and All Souls Hall.

The lenses used with television cameras have a marked effect on the picture quality obtained. The BBC has done much research on this subject and has produced apparatus for measuring the performance of lenses. A BBC specification for camera lenses issued to the manufacturers is now widely used by other television organizations at home and abroad. Close co-operation has also been maintained with British manufacturers in the development of advanced types of zoom lenses. Recently, one has been produced in which the range of variation in focal length can be changed from 4-20 inches to 8-40 inches at the throw of a switch, even while the camera is in use for transmission; formerly it was necessary partially to dismantle the lens and to adjust its position in relation to the camera to change from one range to another. The latest development is to build this lens into the body of the camera itself; in conjunction with a wide-angle adaptor this covers all the normal range of camera viewing angles and apertures.

One of the thirty-six single dressing rooms in the new Television Centre. Other dressing rooms can accommodate 600 artists

telecine Equipment for the televising of film is an essential part of any television service. In the BBC it is used not only for full-length feature films but also for documentaries and for film inserts into studio programmes. BBC engineers have co-operated closely with the manufacturers of telecine equipment over the years, and there has been a steady improvement in this equipment and in the picture quality obtainable.

A problem which arises when a film is televised is that if a normal intermittent-motion projector is used, the resulting picture has a pronounced flicker because the film pulldown time does not coincide with the interval between successive television pictures. This was overcome in the early days by using a continuous-motion film projector, which projected the film directly into a television camera, but mechanical and optical imperfections in the projector mechanism limited the picture quality obtainable.

From the ‘Grandstand’ Studio at Lime Grove the Duke of Edinburgh, on BBC Television, inaugurated, on behalf of the National Playing Fields Association, playing fields in five different places, at Dundee, Rhayader, Liverpool, Hayes and Harlington, and Leicester

In 1949 a great step forward was taken with the introduction of what is known as the ‘flying spot’ telecine machine. In this equipment the film also moves continuously, but the television signal is produced electronically without using a television camera and without the need for the complicated mechanical devices incorporated in the earlier equipment.

Recently a number of telecine channels working on a different system have been introduced. These use a Vidicon photo-conductive camera tube in conjunction with a standard intermittent film-projector mechanism, which lowers the capital cost considerably, while the long life of the photo-conductive tube makes for low maintenance cost.

The BBC has designed much of the auxiliary equipment used with telecine machines, including, at the Television Centre, remote-control equipment, which provides for the remote starting, stopping, and restarting of the telecine machines in a central telecine area from the producer’s desks in the individual studio production control rooms.

film studios Early in 1956 the BBC acquired the Ealing Film Studios and has used them for making documentary films, film inserts into studio programmes, and other items in addition to the footage shot by the Television News Department. The special requirements of television have made it necessary for substantial modifications and extensions to the facilities at Ealing to be designed and planned by BBC engineers, in particular the arrangements for film dubbing (the process of transferring the sound accompaniment of a film from one of the many recording media to another or for adding a commentary to silent parts of a film). Recording or reproducing machines for all forms of sound recording involved in the dubbing process have been installed at Ealing; there are at present some fourteen variations, embracing both 35-mm and 16-mm film. It is also necessary to provide the sound accompaniment for films for export in a variety of forms. A comprehensive sound transfer suite has, therefore, been designed and installed at Ealing. It was brought into use in 1958 and contains equipment for recording and reproducing any of the forms of optical or magnetic sound tracks likely to be encountered, together with disk reproducers and means for running any combinations of the machines in synchronism with one another. The film-dubbing theatre contains facilities for seeing projected pictures and recording a spoken commentary or other sound accompaniment.

The BBC is now the biggest single user of film in the world, and at the Ealing Film Studios alone produces the equivalent of 140 full-length feature films a year. The total quantity of BBC film shot in a year exceeds seven million feet.

The little man – Arthur Askey – in Studio 3 (100′ x 80′ x 44′ high) [30m x 24m x 13.5m]

outside broadcasts (television) An outside broadcast unit consists of several vehicles. The Mobile Control Room contains all the equipment necessary for the generation of television pictures and for the operation of a number of cameras — usually three — which are connected to the control-room vehicle by special cables up to a thousand feet in length. In certain areas, notably in London, there are permanent Post Office television cable circuits which can carry the television signals to the Television Centre for injection into the network. Alternatively, BBC mobile radio links are used. The transmitting and receiving equipment for radio links is installed in separate vehicles, and it is possible to use a number of links in tandem to cover considerable distances. The range over which a single link can operate depends on the nature of the terrain, since normally a line-of-sight path must exist between the transmitting and receiving ends of the link. For this reason the links are often operated in remote locations, such as the tops of hills where no public power supply is available. Additional vehicles are then necessary containing power-generating equipment for operating the transmitters and receivers.

An extension of the idea of mobile units is the ‘Roving Eye’ designed by BBC engineers. The first of these, introduced in 1954, contained in the one vehicle a television camera and all the necessary associated equipment together with radio link transmitters to convey the vision and sound signals to some convenient fixed point. The vehicle contains its own power supply equipment, and pictures and sound can be transmitted while it is on the move. In 1956 a second Roving Eye vehicle equipped with two cameras was produced which greatly extended the usefulness of the unit. Its comparatively small size and the fact that all the equipment is in a single vehicle makes it possible to take it to places where the larger units cannot go.

In 1958 the purchase of a radio camera of French design opened up the possibility of transmitting ‘live’ pictures from locations where this would otherwise have been impossible. The camera with its associated equipment, including a radio link transmitter of BBC design, and its power supplies is carried and operated by one man who can move quite freely, since there are no trailing cables. Modifications to the original equipment designed by BBC engineers have improved its performance and enable the camera to be operated at a greater distance from the point at which its signals are received.

The finals of the Eurovision Song Contest, arranged by the BBC, at the Royal Festival Hall, London, which was seen over the Eurovision Network in fourteen countries. Jacqueline Boyer sings the winning French song ‘Tom Phillibi’

international exchanges of television programmes The transmission of programmes from Calais in 1950 was the first occasion on which ‘live’ television was brought to the British public from outside the United Kingdom; the first time that a television link was set up across an international boundary. The chief engineering problem involved was that of conveying the vision signals from Calais to London, using the transportable radio link equipment which was available at that time. The results obtained were encouraging. Shortly afterwards the French broadcasting authority (R.T.F.) and the BBC began to discuss the possibility of an experimental exchange of programmes between the two countries. Before this could take place, there was need to overcome the technical obstacle presented by the difference in television standards used in the two countries. In France a television standard based on 819 lines is used, while in the United Kingdom the standard is 405 lines; the two systems cannot be directly connected together. Possible means of converting television pictures from one standard to the other were studied both in Britain and in France. By February 1952 the conversion equipment which had been produced gave sufficiently promising results to justify a series of joint R.T.F./BBC programmes. These programmes took place in July of that year; the pictures which originated in Paris using the 819-line system were passed through a BBC standards converter and then fed by a series of portable radio links to London for transmission by the BBC network.

The next step forward came in 1953, when on Coronation Day the BBC television broadcast was relayed by a total of twelve transmitters in France, the Netherlands, and Western Germany. The great interest aroused by this broadcast both in the countries concerned and elsewhere led to discussions on the possibility of more ambitious programme exchanges. Further impetus was given to international relays by the starting of television services in several other European countries. In June 1954 an ambitious series of daily programme interchanges, including eight national television organizations, took place.

From this has evolved the Eurovision network which now links together eighteen television services in fourteen countries. Both the technical and administrative co-ordination of these exchanges is undertaken by the European Broadcasting Union.

Broadcasts from the XVII Olympic Games attracted large audiences, with over fourteen and a quarter million people viewing some of the programmes. In sound programmes and television, using the Eurovision Link, the BBC gave complete coverage of the Games. Peter Dimmock, Head of Television Outside Broadcasts, in one of the Rome Olympic Studios of the Italian Radio and Television Services (RAI)

An improved design of the BBC standards conversion equipment is now installed in the Post Office terminal station at Tolsford Hill, near Folkestone, from where a cross-Channel radio link jointly operated by the British Post Office and the French P.T.T. was brought into operation in 1959, replacing temporary links operated by the BBC and R.T.F.

It may well be that a link capable of carrying ‘live’ television across the Atlantic will be established at some time in the future. Meanwhile, the exchange of programmes between this country and the North American continent has been enormously helped forward by two recent BBC engineering developments. A system was devised for the transmission of 16-mm film pictures for television purposes over the transatlantic telephone cable. This, of course, is not ‘live’ television, but it does enable short news films of events which have taken place on the other side of the Atlantic to be seen in viewers’ homes in this country only an hour or two after the event has happened. The system, known as cablefilm, was used during the Royal Tour of Canada and the United States in June 1959.

The other development, which has been already mentioned, enables videotape recordings to be exchanged between Europe and North America. For this purpose the picture signals are converted from the television standards of the originating country and recorded at the standards of the transatlantic country in which the recordings are to be reproduced. The standards conversion involves not only the number of lines as in European exchanges but also the number of pictures per second. The North American television system uses thirty pictures per second, whereas throughout Europe there are twenty-five per second. A device engineered by the BBC has overcome the flicker in the converted picture which would otherwise result from this difference in the number of pictures per second. As a result, there has been a number of occasions on which European television programmes have been recorded on videotape for transmission in North America and vice versa.

The main BBC Television Control Centre for the televising of Princess Margaret’s wedding. The BBC programme was seen all over the world

colour television After some years of experimental work in its laboratories, the BBC has since 1955 carried out experimental transmissions in colour television. A control room and studio were equipped for colour at Alexandra Palace in London, and colour signals were transmitted first from there and later from the Crystal Palace transmitter at regular intervals for three years from 1955 to 1958. For this purpose the BBC adapted the system used in the United States (the National Television System Committee system) to British television standards. The results of the experiments showed that it is possible using this system to transmit pictures in colour on the channels at present used for television broadcasting in this country. The system is also compatible; that is to say, the pictures can be seen in colour on receiving sets equipped for colour and also in black and white on television sets which cannot receive colour. The BBC is at the present time maintaining a limited schedule of colour transmissions in order to help the radio industry in studying problems in the design of colour receivers.

The results of the BBC’s tests in colour transmission were submitted to the Television Advisory Committee, the committee set up to advise the Postmaster General on the development of sound and television broadcasting on frequencies above 30 Mc/s.

Looking to the Future

Sir Arthur fforde, M.A. (right) Chairman of the Board of Governors and Mr. Hugh Carelton Greene, O.B.E. (left) Director-General of the BBC

H. Carleton Greene, Director-General of the BBC

‘…We in the BBC are ready and very eager to proceed with a small compatible colour service within the framework of our existing programme in Band I on 405-lines, without waiting for a decision on whether there is to be a future move to 625-lines in Bands IV and V.’

Speaking in London, October 1960

‘…In the BBC we consider that the Band III channels not used by ITV should be used to improve the coverage of our existing services and in particular to provide a better service for Wales … if a decision is made to move from our present 405-lines standard to the normal European 625-lines standard this could only be done by using the UHF Bands IV and V … if they were made fully available for broadcasting in this country there would be room in them for four programmes with national coverage. What the BBC suggests is that we, the BBC, should have two of these programmes. One of these would duplicate our existing Band I programme and the other would be a new programme.’

‘…We think that the time has come for the extension of our existing regional and area services into local broadcasting … we believe that the public service system would ensure for the local audience a more genuinely local independent programme than could be offered by any commercial arrangement.’

Speaking in Manchester, November 1960