The History of Television
Events highlighting Rediffusions involvment in the development of Cable Television and the manufacture of TV Receivers in the UK.
Demonstrations of the Baird 240-line mechanical scanning and the Marconi-EMI 405-line electronic systems were given to the Technical Sub-committee of the Television Advisory Committee (TAC).
November 2. Start of regular ‘high-definition’ transmissions, in the London area only, from the Alexandra Palace station, using the above Baird and Marconi-EM I systems alternately, on v.h.f. This was the first regular public high-definition service in the world..
February. The decision to adopt the 405-line system was reached and a daily service by this means began on February 6, from Alexandra Palace. In the pre-war years. the company Radio Furniture and Fittings Ltd, which was subsequently acquired by Rediffusion London Ltd. relayed the television signal by cable, at the transmitted frequency, in blocks of flats on a CATV basis.
September 1. Television Transmissions were suspended for the duration of the war. About 23,000 receivers were in use at that time.
June 6. Transmissions resumed, still from London only, by the 405-line system on a Band 1 vhf. channel. The typical domestic receiver, including the ‘Rediffuser’ (RT.100) made at the Wandsworth factory, had a 9” diameter round-faced c.r.t., 70* deflection, giving a monochrome picture (a commonly-used phos-phor produced a distinctly blue display). The e.h.t. was 5 - 10kV, derived from a mains transformer, and mag-
netic focussing and deflection had replaced the electro-static control of some pre-war tubes. Most receivers were t.r.f.. in keeping with earlier practice. 12” diameter round-faced tubes soon followed. Many home constructors adapted ex - Government surplus radar equipment into television receivers which produced a 5” x 4” green display on a VCR97-type
electrostatic tube. The supply position was such, in the aftermath of war, that one rental company hired out these converted radar receivers.
On 1 June. a new form of receiving licence, permitting reception of television transmissions in addition to sound broadcasting, and costing £2 per annum, was instituted. The hours of television transmissions were from 8.30pm. to 10pm. daily, with a half-time interval.
The number of CATV systems operated by Rediffusion London Ltd in blocks of flats increased, and Rediffusion sold and rented receivers in the London area and, by 1948, in Maidstone also.
Extension of the 405-line v.h.f. service to cover most of the U.K. by four high-power transmitters began. The first provincial area to be served was the Midlands, with the opening of the Sutton Coldfield transmitter on December 17. Holme Moss, for the North, came into service in October 1951, Kirk O’Shotts (Scotland) in March 1952 and Wenvoe (Wales) in August 1952. All four operated on different channels of Band 1, and receivers were pretuned to one station only or had an interchangeable sub-chassis in the r.f. section. Initially at least, some receiver manu-
facturers offered ‘London’ and ‘Midland’ models with different valve compliments and circuits. Later, receivers capable of being tuned to any of the five channels were developed, and the superheterodyne principle was universally adopted. The apparently long delay in making television available to the provinces arose from the need for the Post Office to establish nationwide links capable of handling the signal and from the many competing interests for finance, man-power and resources.
April. The aspect ratio of the picture was changed from 5 4 to 4 3.
The development of a cable television system, operating on a carrier frequency of 11.8MHz was started in the South-East Region, at Margate, during the summer.
In the autumn, Rediffusion began an investigation into large-screen projection television WRS101 using the Philips-Mullard equipment, and a demonstration was given at Carlton House on November 29.
The American National Television Systems Committee (NTSC) began investigation into colour systems, and RCA demonstrated the three-gun shadow-mask colour tube.
Development work on cable television was begun by the Design Department of Central Rediffusion Services Ltd
April 12. The Margate system was officially declared open; the operating frequency was subsequently changed to 972MHz and the system incorporated into TDUK.1.
In the East Midlands Region a pilot cable television scheme was installed, between the Regional Head-quarters and the central showroom, during early 1951; the planning of a complete feeder, for 14M Hz operation, was started during August.
A cable television experiment was also undertaken in the North-West Region, at Eccles, by distributing signals at the frequency transmitted by the BBC on a pair of a squad cable; the first subscribers were connected in October.
Rediffusion provided a cable distribution system for television at the Festival of Britain Exhibition on the South Bank.
Autumn. Wired Radio Service Ltd (the forerunner of Rediffusion Consumer Electronics Ltd) acquired a factory at Surbiton for the manufacture, in the first instance, of 17" projection receivers
developed at the Wandsworth factory.
Wiring of a cable television feeder of the Nottingham system, on the Bells Lane Estate, began early in the year and the first demonstration subscribers were connected in April; the local development of inserts proceeded.
A TDUK.1 system was started in Eccles, on lead-sheathed coaxial cable initially, followed by a subsequent change to aluminium-sheathed coaxial cable.
An experimental TDUK.1 system was also started in a limited area of Hull and in the West Midlands, the wiring for a TDU K.1 operation in Stafford got under way.
April. The first prototype projection receivers were distributed by W.R.S., and the first production models in June.
15” (round) cathode-ray tubes were now available and line flyback e.h.t. had been developed. The number of receivers in use nationally was 1.5 million.
The sale and hire of receivers by Red iffusion spread to the Regions as the signal became available to them; the receivers were mainly those of other manufacturers (Plessey, Marconi, Invicta etc.).
The spread of television throughout the U.K. continued with theconstruction of five medium-power Band 1 transmitters over the period 1953 - 56. Television officially reached the North-East when a temporary low-power station opened at Pontop Pike on May 1 1953. A TDUK.1 system for Middlesbrough was begun, and in February the hundredth subscriber was connected to the Margate system.
14” and 17” rectangular tubes with 900 deflection became available, and at the September Radio Show, models including these sizes predominated, but 21” and 27” direct-viewing receivers were also shown.
July. The NTSC colour signal specifications were completed.
August The number of television licence holders in the U.K. exceeded 2.5 million.
Late in the year a government white paper announced that there should be an alternative television programme.
A rear view of the Plessey 9” receiver
The Television Act provided for the formation of the Independent Television Authority.
October. First experimental colour transmissions were begun by the BBC, using the NTSC system adapted to 405 lines. The WRS 14/17 receiver was in production.
November.The formation of Associated Rediffusion Ltd was announced as a joint venture by Broadcast Relay Service Ltd and Associated Newspapers Ltd, to be the ITA programme contractor for the London area from Monday to Friday each week.
September 22. The first ITA transmitter was opened at Croydon to serve the London area, transmitting on 405 lines in Band 3 vhf. Receivers now had to have a tuner; this was either a switched turret capable of selecting any number of channels up to thirteen, according to locality, or a switched incremental inductance tuner with similar capability. Many of the single-channel receivers were modified by the fitting of a tuner.
October 10. Regular NTSC colour test transmissions from Alexandra Palace were started.
Provincial ITA transmitters opened - for the Midlands (Lichfield) on February 17; for the North (Winter Hill) in May. and for Yorkshire (Emley Moor) on November 3, all Band 3 v.h.f.
In general, the existing TDUK.1 systems (Birkenhead, Middlesbrough etc.) were converted to TDUK.3 (a stackedsystem, having one carrier at 6.3MHz with lower sideband and the other at 9.72MHz with upper sideband, both on one pair of a squad cable), and new cable television networks (Lancaster, Barrow, Darling-
ton, Newcastle, Hull, Nottingham etc.) were engineered for TDUK.2 (two carriers operated tête-bêche, one at 4.95MHz with upper sideband, the other at 8.45MHz with lower sideband. on separeate pairs of squad cables
March. Alexandra Palace transmitter closed down and London service transferred to Crystal Palace.
November. Experimental high-power u.h.f. Band 5 405-line transmissions began, from Crystal Palace.
May. Experimental 625-line u.h.f. transmissions began from Crystal Palace.
Printed-circuit boards appeared in receivers, and 21” tubes (110° deflection, e.h.t. 15 - 20kV) came into general use.
October 13. Thanet celebrated its 10,000th vision subscriber.
December. Video tape-recorders were brought into professional use.
The total of 250,000 Rediffusion vision subscribers was reached early in the year; the national total of television relay subscribers at the end of the year was 450,000, and television licence holders exceeded 10m.
June. The TAC reported their recommendations for the future technical development of television, including colour
September. The Pilkington Committee on Broadcasting was set up to consider the future of the broadcasting services in the U.K.
W. Bruch, of Telefunken, in Germany, introduced the PAL variation to the NTSC colour system.
October. Choiceview Pay-TV, developed by Rank and Rediffusion Research Ltd, was demonstrated to the Pilkington Committee.
July. The Government White Paper resulting from the Pilkington Report recommended that future television services should be to the 625-line standard, in the u.h.f. Bands 4 and 5, and that an ultimate pattern of six television programmes should be aimed at. It also revised the policy regarding Independent Television and extended relay licences for twelve years.
July. A field trial of 625-line cable television was conducted in North London and six-pair cable was accepted as the preferred network of the future
July 11. First Transatlantic television by means of Telstar.
Spring. The Mark 8 receiver, for 625-line uhf. reception, became available. The TD.20 system, for distributing a 625-line channel alongside TDUK.2 or TDUK.3, was developed.
The Government authorized experimental cable Pay-TV.
April. BBC-2 u.h.f. 625-line monochrome transmissions from the Crystal Palace transmitter began. Dual-standard (405-625) receivers were developed with mechanical rotary or push-button operation of
tuning capacitor rotors for u.h.f., combined with a v.h.f. turret tuner and standards switch.
The u.h.f. services (capable of transmitting BBC-2, BBC-1 and ITA) were extended to other areas of the U.K. by eight high-power transmitters (Sutton Coldfield on full power from October 4; Winter Hill in service
from October 31). It was estimated that BBC-2 would be available to half the population of the U.K. by Spring 1966.
Single-standard receivers for 625, u.h.f. only, with mechanically operated push-button tuners appeared. 19” and 23” receivers were in common use, and 27” schools’ receivers were available.
May 24. PAL colour test transmissions began.
The Government announced the decision to adopt thePAL Colour System.
March 3. P.M.G. authorized introduction of colour on BBC-2.
A further nine u.h.f. transmitters were erected. The London Post Office Tower was officially opened, providing for both-way 625 colour city-to-city links.
A solid-state v.h.f./u.h.f. tuner and prototype colour receivers were exhibited in the autumn.
‘Qwist’ (formerly ‘Pod’) twelve-pair cable was de- veloped.
The total of television licence holders reached 13.5 million.
The ITA programme contractors were reshuffled.
Associated-Rediffusion Ltd gave way to Rediffusion Television Ltd with a 50 per cent holding in Thames Television.
July 1. The first PAL colour BBC-2 uhf. programmes were broadcast; the earliest regular coloursystem in Europe.
October. 19” and 25” colour receivers and the Philips six-button integrated tuner were exhibited. Colour receivers included the shadow-mask tube, with 25kV e.h.t. derived by means of a voltage doubler
or tripler circuit from the line transformer.
December 2. Full BBC-2 colour service began.
Electronic or varicap uh.f. tuners, and the Mark 11 dual-standard cable receiver were introduced.
April. The ‘Trinitron’ colour tube was first released. The FC.100 u.h.f. frequency-converter, together with systems for distributing PAL colour 625-line signals in addition to 405-line signals were developed: TD.70,
synchronized carriers of about 5-9MHz on Qwist cables, and TD.80, a tête-bêche system on carriers of about 5.9MHz and 8.9MHz. The disposals of colour receivers to the trade during the year totalled 121,000, and the total of colour licences at the end of June was 34,000.
January 1. The licence fee for monochrome was increased from £5 to £6, and for colour from £10 to £11.
July. ITA transmissions radiated on 625 u.h.f. (as well as on v.h.f.)
Introduction of the Mark 12 single-standard (625) monochrome cable receiver.
November 10-15. At the main transmitters, the BBC-1 and 11V 405-line programmes were duplicated by 625-line u.h.f. transmissions, and the Rediffusion operating companies began the over-night conversion of 405-line channels to 625-line channels and the adjustment of pre-modified cable receivers or replacement of subscribers’ cable receivers to correspond to the new standard.
Disposals of colour receivers to the trade totalled 154.000 for the year.
u.h.f. 625-line colour coverage was extended to most of the remainder of the U.K. during 1970 and 1971.
The Rediffusion Dial-a-Program system was described to The Royal Television Society, and pilot installations were made at the Thames Television Studios and at Cape Cod, Massachusetts.
August 3. The network of forty-seven ITA 405-line v.h.f. stations was completed.
The Philips VCR was available, for sale to ‘organizations’ only.
Production of colour receivers in the U.K. during the first six months totalled 191,000.
British colour receiver production during six months increased to 362,000; the total for the year was 824,000.
Domestic VCRs were becoming generally available (with the exception of the Philips machine, still restricted).
Production of British colour receivers during six months amounted to 673,000.
May 17. Bristol Channel, the Rediffusion local community cable television experiment, was inaugurated.
Relay licences were extended to 1981.
The TD.200 h.f. system was demonstrated, providing for the distribution of 625 colour television signals together with the sound of television and radio by f.m., on hf. carriers; an arrangement permitting the use of
inductively-coupled inserts for all signals, and simpler operation of inverters.
Sales of British colour receivers to the trade during the first six months reached a total of 1,015,000.
Rediffusion 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. The demonstration was a success and comparison could be made between a signal sent over copper or fibre optics. This was thought to be a first for Rediffusion.
The RCE Mark 1 colour receiver in aerial and cable versions was introduced (this was all solid-state except for the line output and boost diode).
June. The IBA installed, at Luton, the first all-transistor 1Ow u.h.f. transposer relay station, of which 200 are to be brought into operation over five years.
September 23, Live teletext broadcasts (digitally-coded signals in the field-blanking interval of 625-line systems) began on BBC1 for a two-year experimental period. The common signals standards for Ceefax (BBC) and Oracle (IBA) were published in October.
RCE produced the Mark 2 colour receiver, with 110° delta-gun tube, primarily for export.
Production of British colour receivers for the first six months of the year totalled 869,000; total colour receivers delivered to the trade during the whole year was 2,209,000.
The findings of the Crawford Committee on Broadcasting Coverage included the TAC recommendation that the duplication of v.h.f. 405-line services by u.h.f. 625-line transmissions should be completed as soon
after 1980 as possible, to release the more effective v.h.f. bands for re-allocation.
The Annan Committee on the Future of Broadcasting received submissions from interested parties.
March 14. The Bristol Channel experiment was terminated.
In-line stripe colour tubes, 90° and 110° in sizes up to 26” diagonal, were first successfully mass-produced.
November. Optical fibres were demonstrated by Rediffusion, as an alternative to electrical conduction for vision signals over trunk routes.
March 29. Rediffusion officially opened at Hastings the first optical-fibre trunk route, in which subscribers to a Rediffusion h.f. system received two of their picturesignals via a glass-fibre trunk cable.
The Hunt Committee recommended rapid expansion of Cable Television Systems, which could be used both for entertainment and, more importantly, for interactive services such as Banking, Business Communications and Shopping creating a "Wired Society"
It was realised that many other programmes would shortly be available
and a new transmission system was designed.
This was known as System 8, it used 5 coaxial cables each carrying 6 TV channels at VHF, this was converted back to UHF at the subscriber connection.
April 27. The Government's publication of a White Paper, which sets out
it's plans fot the expansion of Cable television, is expected to become law in 1984.
The Government supported the Hunt Committee's view that restrictions should be few restrictions on cable operators. They will set up a Cable Authority by law to award franchises. Before that, the Home Office will award 12 licenses to operators who wish to "cable" towns of less than 100,000 people. Rediffusion hope to cable Guildford among others.
For up to five years, existing cable operators like Rediffusion are no longer bound by the "Must Carry" rule. In effect, this means that if they supply the subscriber with an aerialto pick up BBC and ITV, they can use the cable channels to supply other material.
Since 1980, Rediffusion Research had been developing an innovative 30 Channel interactive switched-star cable system (System 8)
with plans to launch the the new system in Guildford for a field trial which was the only franchise that Rediffusion had been given from the 12 franchises awarded. Maxwell Group had by now bought the company. Using a team of advisers from the American company (Viacom) he decided that System 8 was not a viable product. All of the staff based at Coombe were made redundant. System8 ceased to operate and the network was sold in turn to NTL who ran their own broadband signal in its place. Most of the remaining branches now renamed Metro TV, were eventually closed or sold off to other cable companies.
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