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Other than Great Britain, which other countries used 405 lines?
The following countries had operational services for public viewing:
In addition, the following countries chose the 405-line system for demonstration projects before the second world war:
Does any country still use 405 lines?
Not for broadcasting but a fair amount of British archive programming is still held only on 405-line videotape (VT). This means that certain broadcasters, facilities houses and the National Film & Television Archive (NFTVA) have to maintain 405-line VT machines and monitors. In addition, a number of museums and collectors operate 405-line studio equipment, receivers and so on.
What standards did other countries use before 1945?
There were several:
441 lines, 50 fields
441 lines, 60 fields
441, 450 and 455 lines, 50 fields
Why 405 lines - and not 404 or 403 or even 400?
Stephen Hawking's book A Brief History of Time is a weighty tome; heaven knows how large a complete history of time would be. Producing a brief history of television line standards is also a near impossibility, simply because the subject is far more complex than might appear.
So where do we start? The best place is with the product, the television picture. Setting aside new-fangled wide-screen experiments, most TV pictures have had a 4:3 aspect ratio (width to height), the same as most motion pictures. Psychologically this represents a convenient prospect to view without too much head swivelling and ensures that all visual action is contained within a reasonable field of view.
The next task is to choose a horizontal scanning rate which will produce the degree of picture detail required and at the time 405-line television was developed, the maximum bandwidth that vision amplifiers could handle was around 2.5 to 3MHz. This in turn determined the number of lines in the picture, somewhere in the region of 400 to 450.
The timebase circuits in television receivers had to be locked to synchronising pulses sent with the picture signal and generated at the studio; these are a kind of master 'clock' that sets the timing of the whole system. For sound technical reasons, there had to be a straightforward mathematical relationship between the line and field frequencies, the latter being derived by dividing down from the former. Technology constraints of the time meant that this division process could only be made using odd numbers - they had to be integers and ideally 3, 5 or 7 to achieve maximum stability.
Let's take an example. The world's first regular all-electronic television service was British and used a vertical frequency of 50Hz (naturally) and a horizontal one of 10,125Hz (actually cycles per second in those days). How does 10, 125 relate to 50? Easy! 50 x 3 x 3 x 3 x 3 x 5 = 20,250 which divided by 2 gives 10.125. To keep things simple you'll have to take my word that the integers need to be odd ones.
What if we want higher definition? Then we increase one of the multipliers: we know that 3 x 3 x 3 x3 x 5 gives us 405 and by changing the multipliers we find 3 x 3 x 7 x 7 gives 441 (a line standard used in several countries), 3 x 3 x 3 x 3 x 7 produces 567 (used for a while after the war in the Netherlands) and 5 x 5 x 5 x 5 gives us 625. You can ring the changes yourself and see what you get! If this all sounds completely over the top of your head, it doesn't really matter - rest assured your television will still work!
Our original 405-line standard was capable of producing extremely good pictures: in terms of black and white definition it produced more detailed pictures than are seen on most 625 line sets today, simply because the latter are manufactured with such coarse picture element grids that they throw away much of the detail in the PAL picture and disguise this loss of detail with colour. The 405-line standard was used in the UK, the republic of Ireland, Hong Kong and experimentally in several other countries. Most other countries before the second world war used 441 lines (Germany, the USSR and the USA) although France was out on a limb with 455 lines (most of the time). In 1940 the USA established its 525-line standard.
How did the vertical frequency come about?
The picture repetition frequency is also an important factor in the equation. It is generally termed the field rate or frame rate according to your own leanings or the refresh rate if you are a computer person. Since the mid-1930s this frequency has been the same as the mains frequency, either 50 or 60Hz according to the frequency used in each country. This is for two very good reasons. Studio lighting generally uses alternating current lamps and if these were not synchronised with the field frequency, an unwelcome strobe effect could appear on TV pictures. Secondly, in days gone by, the smoothing of power supply circuits in TV receivers was not as good as it is today and ripple superimposed on the DC could cause visual interference. If the picture was locked to the mains frequency, this interference would at least be static on the screen and thus less obtrusive.
When were higher numbers of lines chosen?
During the second world war both the French and the Germans made successful experiments with systems using more than 1,000 lines and there was a general feeling after the war in most European countries that it was time for a fresh start with higher definition (Great Britain and the USA decided to stick with what they had, however).
France opted for an 819-line system which was a bold move to capitalise on war-time research, to re-establish French pride and to protect French manufacturers from foreign competition (the pre-war Paris transmitter, now adjusted to 441 lines, struggled on until 1956 for those with older sets).
The rest of Europe opted for 625 lines, a system devised in 1946 by two German engineers, Möller and Urtel (it appears that the Russians came up independently with a very similar system and if you had set anyone else the problem - to Europeanise the American 525-line standard - they would have come up with something pretty similar). In Geneva a Mr W. Gerber proposed this as a European system and it has remained in use until the present day.
Only the American 525-line system has had a longer continuous 'innings', beating the original British 405-line system, which finally faded from our screens in 1985 (except with the hardy enthusiasts who still keep 405 alive!). The French 819-line system, also used in Belgium, Luxembourg, Monte Carlo, Morocco and other parts of Africa, finally died out during the 1980s, and the only other notable major change to note was the coming of NTSC colour (or is it color?) which necessitated that system to change the vertical frequency in America from 60Hz to 59.94Hz and the horizontal frequency from 15,750Hz to 15,734Hz
Why did some European countries opt for 441 or 455 lines?
Freedom of thought probably. Although the 405-line system was well established in Britain, there was no serious thought of international programme exchange before the war, so the need for total conformity was not a major factor. We have not yet achieved standardisation of computer operating systems or of driving on one side of the road, and there are always arguments in favour of whichever standard you favour. In theory 441 and 455 lines would give marginally better picture definition than 405 lines - marginally.
Why did France choose 819 lines after the war?
International standardisation of television systems was a low priority after the war. Britain was determined to stick to 405 lines, so as not to betray viewers who had already invested in a receiver, and France - as already mentioned - was determined to show the world that the French system was superior to everything else. Perhaps it was but that decision (taken by M. Mitterand, incidentally) was to cost France dear in the end - as did the British decision to stick with 405.
Did television broadcasting and research continue during World War II?
Yes, in some countries. In Britain and France broadcast television ceased just before war broke out, whilst in Italy, which did not enter the war until 1940, television was still being broadcast in October 1939 (no later reports have been discovered).
Quite remarkably television broadcasting in Germany continued as if nothing else was happening. This was intentional of course; just as Germany continued making epic movies in colour as a morale booster, the television service continued as normal. Allied attacks belatedly put an end to this. Hamburgs cable TV service was the first to go, in 1943, and in the capital city the television transmitter was finally bombed and destroyed on 26th November 1943. Even this did not put paid to television in Berlin, since the studio continued to feed the cable TV system and it was only when the studio was requisitioned for film production in autumn 1944 that television broadcasting finally came to an end in Germany.
The hostilities also proved a powerful incentive for research into television in the service of war. At the German secret rocket base at Peenemünde closed-circuit television was used to observe the lift-off of rockets at a safe distance. Again in Germany, Fernseh technical experts developed and demonstrated in 1940 a complete 1029-line television system, the purpose of which was said to be transmitting maps for military purposes. Employing a slide-scanner as pickup device the apparatus gave exceptional results, exceeding 16mm film in resolution. Despite this apparent success, the authorities were apparently unconvinced of the system's strategic value and given its need for 15MHz transmission bandwidth, it is difficult to see how these pictures could have been transmitted with security over long distances.
In France thoughts turned to high-definition broadcast television. Henri de France demonstrated a 567-line system at Lyon in 1941, whilst in Paris work took place in systems employing just over 1,000 lines. As far as public transmissions over the Paris transmitter were concerned, these had ceased in 1939 at the outbreak of war and the revival of the television service was soon far from anyones mind. In June 1941, however, the Germans set out elaborate plans for a European Television service, starting in Germany, Italy and France. The first international collaboration began in March the following year when German and French programming staff agreed to re-open the television service in Paris along the lines of the continuing service enjoyed mainly by troops in Berlin. German and French technicians began to renovate the partly destroyed Eiffel Tower transmitter in June 1942 and a brand-new studio was created. Test transmissions started in 1943, mainly in French, and 200 TV receivers were provided by French manufacturers for hospitals and army messes plus up to 1,000 for private dwellings. The service continued right through the period of the Allied invasion and didnt come to an end until 18th August 1944. Regular television transmissions resumed under French management on 1st October 1944.
In the USA, television broadcasting continued, on a small scale, throughout the war. The Americans also devised airborne television systems for strategic use.
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