The Marconi-EMI studio at Alexandra Palace, 1936
By 1934, the battle to develop a workable high-definition television system
for the UK was on, with John Logie Baird and mechanical scanning on one side,
and Shoenberg's EMI group with all-electronic television on the other. Baird had
taken an early lead with the flying-spot scanner for telecine and moved towards
CRT-based receivers, but EMI was catching up.
By this time, major organisational changes had taken place at Baird
Television Ltd (BTL). After funding shortages, a takeover had been engineered in
1932, with control passing to Isidore Ostrer and the Gaumont-British Film
Corporation. A year later, a boardroom coup ousted Baird from his duties, though
he retained the title of managing director - it was felt that while Baird was
certainly the father of television, he was focusing too much on mechanical
techniques, whereas the future, it was believed, lay in electronic approaches.
Captain A.D.G. West, formerly an engineer at the BBC and EMI, was now
technical director, and it was he who began to crank up the resolution of the
mechanical scanning system, employing faster rotating discs in a vacuum to
improve performance. BTL had moved, in July 1933, to a new facility at The
Crystal Palace in Sydenham, South London which was rapidly being equipped as a
world-class television station and receiver manufacturing plant, while Baird was
effectively banished to the laboratory attached to his new house nearby, free to
develop new technologies but effectively locked out of the day-to-day running of
the company and brought out primarily to meet the press.
EMI showed a 120-line all-electronic system to the BBC and to the GPO, who
regarded it as superior to BTL's latest effort, which was now also offering
120-line images, telecine and a CRT-based electronic receiver using cathode ray
tubes built under licence from GEC. Initial EMI electronic transmission
demonstrations to management in early 1934 were, however, disappointing. Their
mechanical transmission system was now up to 180 lines and the electronic
images, initially, were vastly inferior. BTL's, meanwhile, increased the number
of lines to 180 and began to use VHF for additional bandwidth, as EMI was
already doing.
But by April, EMI had dramatically improved the performance of the Emitron
camera tube and was achieving significantly better results. Shoenberg's team
built a vision mixer with six channels - two telecine and four cameras - and was
able to run a camera outside the Hayes factory by the local canal, as well as
studio-based cameras and film sources to show the system off when the BBC
visited on 18 April 1934.
The BBC's Engineer In Charge of Television, Douglas Birkinshaw, quoted in
Bruce Norman's Here's Looking At You, noted: "No whizzing discs, no mirror
drums: silence, lightness, portability. It showed the way things were going. It
was quite easy to see, even then, that the Baird system couldn't eventually lead
anywhere." He felt that it was inevitable that TV would have to provide outside
broadcasts, and with the Baird system's heavy, fixed equipment, this didn't seem
possible.
Baird's flying spot system had proved particularly successful for scanning
film, thanks at least partially to the absence of focus and depth of field
issues - so much so that flying spot scanning remained the standard telecine
technique for decades. Following this success, Baird had borrowed an idea from
his licensees in Germany, where they used a film camera to shoot studio images,
the film going instantly into baths of developer, fixer and then water, being
scanned while underwater by a flying spot scanner.
The British implementation of the system - called the 'Intermediate Film
Technique' - worked, some of the time, but it had problems: underwater
air-bubbles interfered with the sound, and it needed lethal cyanide developer to
get the processing time down to 'almost instantaneous' - in fact it took just
under a minute. The lurid orange developer was notorious for leaking out of the
system and on to the studio floor. The in-line processing and scanning equipment
made the assembly so heavy and bulky that it had to be mounted in a special
bay-windowed room in the studio where it could not be moved, in stark contrast
to EMI's comparatively small, light Emitrons.
BTL, obliged to begin to consider electronic transmission technologies,
somewhat half-heartedly struck up a relationship with American Philo T.
Farnsworth, another claimant to the title of 'Inventor of Television'.
Farnsworth's system, despite major flaws that Baird might have been able to sort
out, did produce electronic pictures, but it needed extremely high light levels
and BTL was seldom able to get it to work properly, necessitating personal
visits from Farnsworth to tweak the temperamental machinery. Part of the deal
with Farnsworth, however, gave BTL access to useful electromagnetic deflection
technology for CRT-based receivers
High-Definition Considered
In mid-1934, the government set up the Selsdon Committee, under the
chairmanship of Postmaster General Sir William Mitchell-Thompson, now Lord
Selsdon, and including BBC, government and GPO representatives. Its job was to
evaluate the possibility of replacing the existing 30-line low-definition
service with a high-definition successor, and which system to use to do so. BTL
and EMI were not the only players, with alternative offerings from companies
such as Cossor and Scophony and a couple of others, but it was evident that the
first two were the primary contenders.
BTL was by now offering an array of technologies, including 30-line flying
spot, Intermediate Film at 180 lines and telecine at 240 lines, 25 frames per
second, all using mechanical scanning. There was also the Farnsworth
all-electronic option - if they could iron out its problems. Its Crystal Palace
facility, though at this time out of the limelight, was enormous, and
represented the most fully-equipped television studios in the world. Now making
regular test transmissions at 180-line resolution, BTL, in April 1934, murmured
about applying for a licence as an independent broadcaster, transmitting from
the top of the South Tower at the Crystal Palace, over 600 feet above sea level
and in view of seven counties, at a power that would cover the entire Greater
London area.
EMI, having now set up a joint operation with Marconi to provide it with
transmission capability, was officially offering 240-line mechanically scanned
telecine and little else - its electronic system was still effectively in its
infancy. In an almost incredible leap of faith, Shoenberg decided to take the
plunge and committed the Marconi-EMI team to delivering 405 lines, 50 interlaced
fields per second - and, giving up drum scanning, to all-electronic signal
generation. It was a major milestone. It was also beyond the team's capabilities
at the time of the announcement, and it was likely that the first receivers
would not do the system justice. Marconi-EMI had specified a system that allowed room
to grow - but one that would be difficult to achieve so early in the game.
The difference provided by the interlaced field system was that while the
Baird approach delivered 25 complete 'pictures' per second, one after the other,
the EMI system sent two 'fields' - one containing alternate lines in the picture
and the other filling in the gaps - in the same length of time. So although both
sent 25 complete pictures per second, the EMI system, with its 50 interlaced
fields per second, was much less subject to flicker. Moreover, having almost
twice as many lines made the line structure much less apparent. In fact, the
structure of the EMI television signal was so carefully thought out that it
became the basis for television standards all over the world for many years to
come.
The Selsdon Report was published on 31 January 1935, and Lord Selsdon
announced that there would be a high-definition (defined as a minimum of 240
lines, 25 frames: the limit of the Baird system) BBC Television Service - but as
the Committee couldn't (or wouldn't) decide between Baird and EMI, it chose
both. The two systems would run side by side, alternating weekly, under
evaluation for six months, after which a permanent system would be chosen.
After the event, it became evident that there had been political motives
behind this complex, wasteful, expensive and perhaps typically British
compromise. Baird was a high-profile figure, who had even impressed the Prime
Minister with a demonstration. Leaving him out of the world's first
high-definition television service would have resulted in serious public
criticism of government and Post Office alike. In addition, the bankruptcy of
BTL was seen as a real possibility, and once again the government did not want
to shoulder the blame for such an eventuality. Finally, including BTL in the BBC
Television Service would perhaps help dissuade the company from going it
alone.
The day after the Report was published, however, journalists were shown
around the previously little-known, but extremely impressive, Crystal Palace
facility. Geoffrey Edwards, the News Chronicle radio correspondent, wrote on
Saturday, February 2, "Any search by the BBC for a site for the promised London
Television station would, it seems, be a waste of time when the Crystal Palace
station is there ready for use." But it was not to be. (As a further blow, on 11
September 1935, the BBC closed down its low-definition service, orphaning the
several thousand medium wave 30-line mechanical Televisors already in the
marketplace. They would never receive programmes again.)
High-definition TV was coming to London, and the BBC had just eighteen months
to do it. Gerald Cock, formerly the BBC's outside broadcast director, was
appointed Director of the new BBC Television Service.
|