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Old 20th Feb 2004, 2:06 am   #1
Steve
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Default 405 line standard outside the UK

Was the 405 line UK system used anywhere else in the world, apart from Ireland?

And, if so, when did these systems shutdown?
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Old 20th Feb 2004, 3:31 am   #2
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Default Re: 405 line standard outside the UK

The following countries had operational services for public viewing:

Gibraltar
Republic of Ireland
Hong Kong (a cable-only 405-line service opened there in May 1957).
In addition, the following countries chose the 405-line system for demonstration projects before the second world war:

Czechoslovakia
Netherlands (Philips Ltd test transmitter)
Switzerland.
 
Old 20th Feb 2004, 3:40 am   #3
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Default Re: 405 line standard outside the UK

Bit of useless information for you France where the odd balls with an 819 line system.....i have a french portable sony tv that has 625 secam/819 lines.

 
Old 20th Feb 2004, 9:35 am   #4
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Default Re: 405 line standard outside the UK

I have read that you could resolve an 819 line picture on a 405 set. You would get 2 half width pictures across the screen. Seems reasonable as the line length on 819 was almost exactly half that on 405. Can't imagine the resolution would have been too great with the limited bandwidth of a 405 set.
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Old 20th Feb 2004, 3:55 pm   #5
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Default Re: 405 line standard outside the UK

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Bit of useless information for you France where the odd balls with an 819 line system.....i have a french portable sony tv that has 625 secam/819 lines.
Any idea why the French never pursued colour on the 819 line system?

Last edited by Paul Stenning; 29th Dec 2004 at 1:54 pm.
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Old 20th Feb 2004, 4:04 pm   #6
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Default Re: 405 line standard outside the UK

They could have done. Any of the colour systems could have been adapted to 819, just as NTSC was tried successfully on 405. The French decided, as we did, that being out on a limb with a unique standard was not a good idea. Also the 819 channel was 11MHz wide which made multichannel broadcasting a big problem. When 405 started in 1936 the technology of the day could not fully utilise the resolution of the system. Likewise with 819, except that 819 was scrapped before the technology caught up. If 819 had stayed it could perhaps have been the basis of HDTV (in the modern sense).
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Old 20th Feb 2004, 4:13 pm   #7
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Default Re: 405 line standard outside the UK


The French 819 line system was HDTV before its time, but it was bandwidth hungry; and the compromise bandwidth restriction of system F completely defeated the object. As far as i have been able to find out, no 819 line colour experiments were ever conducted.

I personally wish we still had 405 there was more space by now we could have had 13 channels and the colour support from the tests done was very exceptable.
 
Old 20th Feb 2004, 4:17 pm   #8
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Default Re: 405 line standard outside the UK

In about 1987 I published an April Fool spoof in Television magazine. It was called something like " 405 MAC, a new system for HDTV " . The numbers added up quite well, you could have just about implemented my ideas, and people seemed to have enjoyed it at the time. The best laugh was at a Royal Television Society meeting where I overheard 2 guys discussing the article as if it was genuine. I crept away quietly with a smile on my face
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Old 20th Feb 2004, 4:45 pm   #9
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Default Re: 405 line standard outside the UK

sounds like you had them fooled

i was 16 when they turned off 405 i can remember our old tv set ... we got a bush colour to replace it when they shut off 405.
 
Old 20th Feb 2004, 5:01 pm   #10
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Default Re: 405 line standard outside the UK

I have heared that the french had 441 before 819.
The old german system is compatible with the english
405 system. I think the technicans worked together.
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Old 20th Feb 2004, 5:07 pm   #11
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Default Re: 405 line standard outside the UK

I don't think the British and German engineers worked together. The need was for an odd number (for interlace) that could be factorised into small integers. Early frequency dividers were usually made from synchronised oscillators. This is difficult to do for large divisors.

243 = 3*3*3*3*3 (original EMI standard)
343 = 7*7*7
405 = 3*3*3*3*5 (final EMI standard, legend says that Blumlein said " let's change a /3 to a /5 " )
441 = 3*3*7*7
525 = 3*5*5*7
625 = 5*5*5*5
819 = 3*3*3*7*13
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Old 20th Feb 2004, 5:19 pm   #12
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Default Re: 405 line standard outside the UK

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They could have done. Any of the colour systems could have been adapted to 819, just as NTSC was tried successfully on 405. The French decided, as we did, that being out on a limb with a unique standard was not a good idea. Also the 819 channel was 11MHz wide which made multichannel broadcasting a big problem. When 405 started in 1936 the technology of the day could not fully utilise the resolution of the system. Likewise with 819, except that 819 was scrapped before the technology caught up. If 819 had stayed it could perhaps have been the basis of HDTV (in the modern sense).
Are they not out on a limb anyway with the SECAM system? I can understand everyone standardising on 625 line to keep the same channel spacing throughout Europe, but given they went for a completely different colour system (although I believe you can resolve SECAM in B&W on a PAL set?) why not go the extra mile and stick with 819 lines - I mean, it's not like the French to conform. Or was it some European directive regarding channel spacing?

That said - Anything is better than the scrappy quality I seem to get from the digital satellite. The technical abilities system itself seems OK but as with any system (same with DAB) where you can adjust the channels v. quality - the former always wins. Something which was never a problem with analogue.

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Old 20th Feb 2004, 5:30 pm   #13
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Default Re: 405 line standard outside the UK

This seems very different, but it is not. You don't have
to change anything in the TV set to receive both 405
and 441 line systems.
Now we have the american system. You only have to
turn V-hold and hight if you want to use an US-TV
in EU. I am not talking about color!
The manufracturers of TV sets want a big market
this was so and will be so.
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Old 20th Feb 2004, 5:36 pm   #14
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Default Re: 405 line standard outside the UK

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Something which was never a problem with analogue
Ask anyone who watched TV in the USA, especially colour.

In the early 1950s NTSC was the only game in town. It suffered badly from distortions in the transmission and recording processes. The PAL system derives from work done in the late 1940s at Hazeltine labs in the US. Bruch at Telefunken turned these ideas into the PAL system. A French team was solving the same problems at the same time. They arrived at SECAM. PAL was more complex than SECAM. SECAM was more rugged than PAL and could be recorded on a standard monochrome Quadruplex recorder. SECAM was also a rotten system for vision mixing, special effects etc.

Each country then made its own choice. Britain went first and chose PAL. Germany and others followed. Francophone countries went SECAM, as did the Soviet bloc. The Soviets went SECAM partly because it made sense with their very long tranmission chains, partly because the French " encouraged " them, partly because the Soviet copies of Quadruplex recorders did not have the " Colortec " or similar correctors that would have enabled them to record PAL.

Transcoding PAL/SECAM was not too difficult (not like 50Hz/60Hz conversion) and the French often ran PAL in the studio for ease of vision mixing. It also pushed them to be in the vanguard of component analogue studio systems. The Soviet bloc, especially the Bulgarians, doggedly used SECAM in the studio which, I can assure you from direct personal knowledge, is a masochistic way to do it.
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Old 20th Feb 2004, 5:40 pm   #15
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Default Re: 405 line standard outside the UK

405/441 does not matter at the receiver. Just look at the flexbility of modern multisync monitors which handle a vast range of line and field rates.

It matters a lot in the studio where all the pulse generation etc has to be on the correct standard.

Engineers from a TV background curse the computer folks who proliferate standards.

We love standards. Everyone should have their own
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Old 20th Feb 2004, 6:12 pm   #16
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Default Re: 405 line standard outside the UK

oh,tnx for the info about color I did not know this.
In east Germany they had secam. But they made PAL
after the reunifikation (hope this is the right word).
People from east germany told me they had dual
standard TV's and so it was no problem for them.
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Old 20th Feb 2004, 6:15 pm   #17
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Default Re: 405 line standard outside the UK

Yes and I have 416 2/3
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Old 20th Feb 2004, 6:23 pm   #18
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Default Re: 405 line standard outside the UK

NTSC = Never Twice the Same Colour
SECAM = System Essentially Contrary to the American Method
PAL = Peace At Last

SECAM was seriously considered in the UK, with support from a number of engineers, notably Michael Cox who left ABC Television in 1967 when they lost their franchise and started his own company. Michael Cox Electronics made a lot of SECAM studio equipment, as well as PAL and NTSC. I worked for them in the early 1980s. My first project was improving some SECAM test gear. I may understand SECAM but I still don't like it!

PAL, in the version that we finally used, was actually a latecomer. I'm glad it arrived in time to save us from SECAM. The BBC strongly supported a 625 version of NTSC for quite a while. With modern technology this would be no trouble and give really excellent results. In the mid 1960s it would have meant rather variable quality colour.
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Old 20th Feb 2004, 7:53 pm   #19
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Default Re: 405 line standard outside the UK

Thanks everyone - Lots of interesting info.

I've seen NTSC in the states. It looks OK-ish but it's difficult to judge. A lot of TV sets I see in the UK are pretty dire. Next time I go over I'm keen to check out the hi-def sets they now have.

You mentioned distribution systems. Are they typically all digital these days? In days of yore, how was the BBC distribution done - was it composite rather than component? I would have thought they'd at least keep it component up until the final haul?
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Old 20th Feb 2004, 8:14 pm   #20
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Default Re: 405 line standard outside the UK

Distribution isn't really my scene but here goes.

Between 1969 (duplication of BBC1 and ITV on 625) and 1985 (405 shutdown) distribution was all 625. Converters, first analogue, then digital, were used at each main transmitter site.

From 1967 (start of colour) analogue distribution was always in PAL composite. Then sound-in-syncs was added to save a separate sound channel. This puts digitally coded sound in the sync pulses. Stripped off before it goes to the transmitter.

Composite digital distribution was used, and probably still is used. AFAIK the signals going to the analogue terrestrial transmitters were and are always composite PAL, whether digitised or not. It is possible that has changed since digital terrestrial transmissions. These are inherently component and should never have seen a PAL coding process ever. It would make sense to send component signals to each main TX, then PAL code for analogue and COFDM code etc for digital.

Is anyone more up to date than I am?

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