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Old 23rd Feb 2011, 2:48 pm   #1
murphyv310
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Default 240, 405 & 625

Hello.
I have been watching another thread about the Baird Phosphors, the thread had I felt got quite heated with some 405 knocking and reference to 240 lines as well.

I was always under the impression that the forum was for like minded people that enjoy what we do as a "hobby". Now I really think that we have to respect peoples views but also realise that there are persons on this forum with an outstanding knowledge of old Television systems.

My feeling just because something is old it certainly is not inferior, and just because the 405 line system is old it is certainly not inferior, now that comes with some provisos. When the system was tested on air it as we know was in direct competition with the Baird 240/25p system, the 405 line system won and rightly so, the reason! Simply because of entertainment value the field rate (refresh rate for computer addicts) was too low, the flicker was far to objectionable. Think of it this way, you are a computer programmer and sitting in front of a CRT monitor and the refresh rate is 60hz it would not be too long till you got a headache. This would have been the case if the Baird system had won.
OK I think if the Baird system won it would not have been carried on after the war like 405 did.
The 405 line system was technically advanced, a terrific feat of skills when electronics was in its infancy, the picture quality was excellent with no objectionable flicker and excellent picture resolution.

There was no reason to have a 625 line system after the war, it would have been very unpatriotic for a start and costly, we had a reasonable number of perfectly good pre war sets to recommission and I think the government did the right thing.

Tube sizes were still 9 to 12 inches and even on 14 and 17 inch sets the picture quality was excellent, remember the horizontal definition on 405 is the same as 625.

We then got lambasted by the 625 line brigade headed by Irishman C O Stanley of Pye, for some reason he hated 405 and very publicly made it well known.

I think we all know the rest, my argument will always be for 405, it was "our" system, it produced beautiful pictures often admired by the French, it kept our industry alive, it required less transmitter power so was "greener" than 625/UHF, and NTSC 405 line colour is excellent.

To sum up 405 was and still is a great system 240 was no good, it's as simple as that, 625 is a good system too, like 405 it has drawbacks, 405's biggest drawback is the line structure on large screen sets 25 inch and over, I personally don't like the huge TV sets on offer now and wouldn't have one in my house.
Lastly, perhaps if we stuck with 405 a bit longer perhaps we would still have a TV industry & Trade.
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Old 23rd Feb 2011, 3:01 pm   #2
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Default Re: 240, 405 & 625

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Originally Posted by murphyv310 View Post
...When the system was tested on air it as we know was in direct competition with the Baird 240/25p system, the 405 line system won and rightly so, the reason! Simply because of entertainment value the field rate (refresh rate for computer addicts) was too low, the flicker was far to objectionable.....
Now that's a contentious statement. Yes the large area flicker was a problem but the main reasons M-EMI won were not really to do with having 405i50 rather than 240p25. M-EMI had a well developed system capable of multicamera studio work and OBs. Baird had a good telecine, with nothing at the time that could do decent live pictures in a practical production environment. Given time and effort they might have been able to develop the image dissector camera or possibly even make an attempt at other electronic cameras. The fact is that at the end of 1936 they didn't have any of this working.

As Paul Marshall has said, there is no fundamental reason why TV should have developed along the "live" model as it did. It could have been a largely film based service, where Baird's telecine would have been an advantage. The fact is that it did develop as a live system so Baird, and hence his system, had to lose.
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Old 23rd Feb 2011, 3:10 pm   #3
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Default Re: 240, 405 & 625

Quite possibly Jeffrey and I will bow to your superior Knowledge, I suppose that a system though would need live capability.
Surely though subjective tests were carried out and I do know they were, the feedback from these tests were certainly not very good for Mr Baird and his team!
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Old 23rd Feb 2011, 3:21 pm   #4
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Default Re: 240, 405 & 625

I suspectthat even if the Baird pictures had been excellent and the M-EMI ones mediocre, M-EMI would have won simply on production issues. Cueing the spotlight and IF studios was a nightmare, there was no possibility of multicamera work and reliability was even worse than M-EMI.

I'm pretty sure that the emitron cameras were cursed regularly by engineers and producers alike (I have seen early postwar documents in the BBC Archive where the acrimony is tangible) but that must have paled into insignificance compared to the trials and tribulations of spotlight and IF.
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Old 23rd Feb 2011, 3:26 pm   #5
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Default Re: 240, 405 & 625

Hi.
I have been doing a fair old bit of reading today about some of the problems encountered back then and the pains that people from both systems went to, to ensure all went well. It would seem that there was a lack of detail when watching a film on the 240 line system, I just wonder if that could be the flicker? Then 405 was not that brilliant with film either but 405 pictures from live camera work was very good.
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Old 23rd Feb 2011, 6:12 pm   #6
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Default Re: 240, 405 & 625

The whole point of the electronic Marconi EMI system was that it was capable of outstanding results, mobile and instant! In the early days the Emitron cameras were rolled out onto the terrace at Alexandra Palace and live 'outside' broadcasts transmitted. This was followed in early 1937 with a completely independent outside broadcast unit mounted on an AEC lorry chassis. Absolutely incredible and years ahead of it's time. The results, given a good signal path to Highgate were excellent. All this was impossible to achieve with the ludicrous Baird I.F. system. He must have stood in the background during the electronic transmission weeks and realized there was no competition and the outcome would be obvious. The whole idea of television was that it was to be 'film less' and the processing and scanning although clever was nothing more than a contraption.
The 405 system was indeed incredible remaining little changed from it's 1936 concept and to continue it after the war was without doubt the right decision. It also gave our manufacturers a head start to post war production of receivers. If we had changed to a 625 CCIR system our industry would have gone under due to imports fifty years before it eventually did. It is also forgotten that we exported very large numbers of 625 line receivers during the 50's and 60's continuing into the 70's. I don't think a 625 line picture would have been any better if as good as 405. The picture tubes of the time would have had a problem focusing such a small spot size and any increased bandwidth would have been lost to the final viewer. 405 line pictures produced on 21" and 24" tubes are truly excellent given a reasonable viewing distance as can be seen by pictures produced on the Philips 21TG100U series and many others. 405 held it's head well above the rest for years beyond it's sell by date and is still making a pretty good show even today via the AURORA. It was also and most importantly loved by it's users. I was there and experienced it first hand. Regards, John.
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Old 23rd Feb 2011, 6:35 pm   #7
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Default Re: 240, 405 & 625

Hi John.
Many thanks for your post, just what I was trying to say in a nutshell.
I find that some younger people are greatly mis-informed about the 405 line system and the great pleasure it brought to many families.
The press and the media in a lot of cases seem to knock 405, and for that matter analog systems in general.
I always believe that you don't get something for nothing in this world and that is the case with Digital platforms.
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Old 23rd Feb 2011, 6:39 pm   #8
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Default Re: 240, 405 & 625

As I've effectively said in the previous thread, please bear with me!
I am not at liberty to divulge the bulk of my findings at this stage, but the summary of this part of my work is:

1. Television did not have to develop the way that it did - film interests could have dominated.
2. There were good reasons for the UK being 'first', despite the fact the USA had developed the bulk of the technoolgy and was 'ready to roll' before us.

The technology was always going to be secondary to the politics - the fact that 405/50 'won', is a fact that has been presented as inevitable. It wasn't, just as it wasn't inevitable that the BBC should run any TV service - especially in the mid 1930s when the BBC was being pilloried in the press and by sections of the public. If the 'rules' of the competition had been about 'film to home', then BTL COULD have won. If a proper patent pool had been organised (as envisaged by the Television Committee), BTL could have had interlace. If EMI hadn't linked up with Marconi (gaining RCA patent rights on 'transmission'), they would have had no rights to build the Emitron. I could go on. Some will say that this is all speculation and/or counterfactual - but it's all about people, politics and power.

I could go on for hours (and do - in my thesis!), and I don't pretend to have all the answers. What I have learned from this six years of study is that the more you know, the more you realise that there's a lot more to know. We have had numerous books on TV history, of varying quality, all contributing *something*, and I hope that my work, in the modern tradition of the History of Science and Technology, will reflect more deeply upon contemporary issues beyond the *obvious* techie bits. As an engineer, it's taken me a long time to appreciate this, but that's because I care about engineering and its 'importance'. The cold hard facts are that the techie side is but just one aspect.

625/50 turned out to be the best compromise for the 1950s and beyond - of that there is no doubt - and no matter how warm the memories (and the valves!), we must put this into a global context. Yes, we did quite well, but so did the USSR, France, Germany, the USA and even places such as Australia which didn't follow our 'lead' into 405, launching on 625. Also, it must be appreciated that countries such as the USA and the former USSR are/were HUGE, with tx problems that we could only gawp at. Our compact little islland produced other issues with channel allocation - that's true - but we never faced the issues of the larger countries and their diverse structures.

I'll get off of my soapbox!

Best regards,

Paul M

PS The Emitron was variable - when it was good it was good, when it was bad, it was rotten. As a telecine, it just couldn't hack 'cuts' because the 'tilt and bend' operators couldn't work that fast! It had other issues too, but with regards to the BTL telecine - it was noted that the pictures began to deteriorate as the end of the trial approached - poor maintenance was the culprit, I believe. Fundamentally, despite its mechanics, it was sound.

PPS All this talk of 'Baird' has also to be clarified. JLB was effectively out on a limb from his own company by 1934, and the Ostrer brothers (owning Gaumont British) were in firm control, establishing the 'other' television centre at the Crystal Palace - an amazing set-up of studios, transmitters and production facilities which burned down in the CP fire. There's things that were going on there that need to be brought out, as books such as Burns' epic don't address them. Only an academic thesis has so far looked at this in detail, with pictures that would astound you, but not so far 'on general release', except via the BL.
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Old 23rd Feb 2011, 6:52 pm   #9
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Default Re: 240, 405 & 625

Hi Paul.
An interesting answer! A bit ambigious though. The course of history can change with a flick of a coin, there may be many reasons why a different outcome could have happened, just like you may not be here if your mum had met a different person! We have to forget outside influences and realise what the course of history has revealed.

OK you are doing a thesis, but it does seem rather biassed toward a system that after the war was largely untested and was not in keeping with our national pride of the time.
We now have little or no national pride and if the same situation was to happen now we could well have 625 as our TV system.

Being older, I have no doubt we did the correct thing and used a good known system up to '85.
I would also suggest that anyone saying 405 lines was rubbish go to "specksavers"!
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Old 23rd Feb 2011, 7:06 pm   #10
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Default Re: 240, 405 & 625

With all due respect, how do you know that you're older?

I'm 54 (today, actually!). I've been doing this part time whilst in full-time employment in the flight simulation industry.

Over the years, I've also designed and built an image iconoscope camera (about ten years ago), shown at IBC, rebuilt to working condition two full 12 ton OB trucks with all their gear restored to working condition, and now working on a 1953 405 line one.

I DO understand about the 405 nostalgia and have the gear to prove it!

What seems to be hard to get across is that we in the UK didn't have some 'right' or 'ability' for television - there's plenty of other countries and people out there who were just as good in different ways. We went our way, for good or bad, but there are things beyond the 'techie' which if we are thoughtful, we must address. As I said, it's taken me a long time to learn that - and I'm still learning. Knee jerk doesn't work in the end; you need, in the modern idiom, to think outside the box . . .

Cheers,

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Old 23rd Feb 2011, 7:24 pm   #11
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Default Re: 240, 405 & 625

If we extend this thread to include 819 there must be a similarly interesting history to be researched about the French system. As I mentioned in another thread this never really attained its potential. The contrast between this and 405, which rapidly attained its full potential, might well be instructive.

There were also 1000 line HD experiments in the 1950s. Pye(?) made equipment for making films using TV cameras. Again this looks like a system too far ahead of its time.

With the benefit of hindsight, we can see that 625 (and 525) served the world very well for a long time. It has taken a long time from the first demonstrations of 1080 line systems (1125 total lines) to general deployment as a public service. Apart from various techincal problems, it could be argued that 625 and 525 were entirely good enough, certainly good enough for there not to be a public clamour for HD. Of course the 405 system could have provided the basis of a modern high definition system. I wrote about this in April 1987
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Old 23rd Feb 2011, 7:27 pm   #12
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Default Re: 240, 405 & 625

Hi Paul.
Yes indeed I "am" older, not a lot though. I am fully aware that we certainly we don't have the "right" with TV, there were many experiments and good work done elsewhere and contrary to what a lot of people mistakenly think, Eastern Europe and some of the Russian states come to mind let alone other places dotted around the world.
I understand you have done a lot of work too and well done for it.
I am not old fashioned, if I was I wouldn't be here on a PC or listen to a dab radio or watch freeview.
In a way you have to see it from the other end, the consumer, the engineer out in the field etc. The designers come up with something they think is better whether its a remote control, I-pod, BBC2 etc.
In the years I was a TV engineer in the early days especially customers loved their 405 line sets and yes the system had drawbacks, interference, aircraft flutter, the line whistle etc. The majority of people loved 405 and even those on dual standard sets after duplication still used 405, so no matter what we think the feedback was telling us what the general public was happy with.
This situation still exists with complex menu's to work around even to record a TV program.
I am all for progress but why all the complication?
I often would have loved the "designers" to spend a week or two with me perhaps things would be different.

I would like to see some of your work by the way, it certainly sounds interesting.



Jeffrey the 405mac does sound interesting along with all the advantages of the 405 line system, it certainly would have been better for our industry and I still might be fixing TV's now for a living!

Last edited by murphyv310; 23rd Feb 2011 at 7:29 pm. Reason: Added line
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Old 23rd Feb 2011, 7:45 pm   #13
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Default Re: 240, 405 & 625

Back in 1962-63 British Relay did experiments under Henry Chmiel's wing of interpolating 405 basically doubling up the picture, each line was sampled and fed into a store and then compared with the next transmitted line, the difference was then used as a supplementary line, back in those days the equipment was massive to say the least and very temperamental, but it worked very well and the result was excellent especially on 23 and 25 inch tubes.

Henry had some cine film of the results which he showed me in the early 70's
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Old 23rd Feb 2011, 7:48 pm   #14
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Default Re: 240, 405 & 625

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Back in 1962-63 British Relay did experiments under Henry Chmiel's wing of interpolating 405 basically doubling up the picture, each line was sampled and fed into a store and then compared with the next transmitted line....
Can you give a reference for that. The only line store technolgy that I know of from that era was the set of capacitors and switches that the BBC used in the CO6/501 625>405 converter. I suppose it might have been possible with glass or mercury delay lines.

What you are describing is a very simple line doubler. This approach, while impressive on static pictures, can give unpleasant results on moving ones due to interlace.
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Old 23rd Feb 2011, 7:56 pm   #15
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Re: << The majority of people loved 405 . . .>>

I would suggest that what they loved were the programmes and actually having a TV in their home. It's true that people tended to continue with 405 after buying/renting a dual standard set, but we all know that those sets were pretty goose (in general) on 625/UHF, with all their compromises for dual standard working. Not a patch on a single standard continental set of the time, so I'm informed by people who witnessed both. That's well outside my time period of study (I stop at 1939), but it could be the subject of a paper some day! I will be needing reliable and provable references though . . .

Cheers,

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Old 23rd Feb 2011, 7:56 pm   #16
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Default Re: 240, 405 & 625

The chance of being able to get info is probably not too easy, as far as I know Henry died some years ago, I think he would be well over 100 if he was still alive, the other person that would have helped would have been Eric Cooke, the last time I spoke to him would be 1976.
Whether Mike Mearman would be aware of these experiments I have no idea.
British Relay had quite an amazing R&D dept and most of their equipment was designed in house, their delay line colour lock units were designed by engineers in house as was their MR756 receivers with synchronous detectors although Murphy Radio actually built them.
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Old 23rd Feb 2011, 8:01 pm   #17
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Re: << The majority of people loved 405 . . .>>

Not a patch on a single standard continental set of the time, so I'm informed by people who witnessed both. That's well outside my time period of study (I stop at 1939), but it could be the subject of a paper some day! I will be needing reliable and provable references though . . .

Cheers,

Paul M
We actually exported many 625 line TV sets from the late 40's to the early 70's and they gained an excellent reputation abroad.

If our Dual standard sets were so bad at the time why are they now once restored now giving excellent results without the horrible grey pictures they did in the mid 60's. I think it was only after duplication that 625 was any good here.
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Old 23rd Feb 2011, 8:16 pm   #18
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Default Re: 240, 405 & 625

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We actually exported many 625 line TV sets from the late 40's to the early 70's and they gained an excellent reputation abroad.

If our Dual standard sets were so bad at the time why are they now once restored now giving excellent results without the horrible grey pictures they did in the mid 60's. I think it was only after duplication that 625 was any good here.
First and foremost I think the problem was UHF, not 625. The PC86 and PC88 may have worked at UHF but only well enough for local reception. In most cases we can now feed our sets with decent signals, strong enough to overcome this problem.

Single standard sets were always going to be easier than dual. Hence a UK built 625 export TV22 etc would be as good as a 405 version. Remember we were exporting VHF 625 sets, not UHF.

Mean level AGC will always give fade to grey instead of fade to black. Not many dual standard sets had DC restoration.

I look to Brian Cuff or others who worked at the BBC during the start of 625 to say how the pictures compared at the sending end.
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Old 23rd Feb 2011, 8:25 pm   #19
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Default Re: 240, 405 & 625

Quote:
We actually exported many 625 line TV sets from the late 40's to the early 70's and they gained an excellent reputation abroad.

If our Dual standard sets were so bad at the time why are they now once restored now giving excellent results without the horrible grey pictures they did in the mid 60's. I think it was only after duplication that 625 was any good here.
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I'm not sure that I'd say that restored ones are 'excellent' on 625 (having done a couple myself and seen many more). The 'grey' pictures of the time were probably largely down to low-gain valve UHF tuners having short lives. With restricted use, this situation probably doesn't arise now. Then there's the problem of poor UHF signal strength in a lot areas, exacerbated by inadequate aerials. I've yet to see a mid-sixties one that is really good on 625 - but I have an open mind on that.

If you have a reference for your << excellent reputation abroad >> it would be useful to post it; my impression has always been the opposite!Does the Setmakers have anything to say on this?

Now, I really MUST get back to my writing!!!!!!

Cheers,

Paul M
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Old 23rd Feb 2011, 8:26 pm   #20
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Default Re: 240, 405 & 625

Fair enough Jeffrey but and its a BIG but even those on really strong signals were still having the "grey" effect on BBC2 then the same set is much better after Duplication.

I understand about DC restoration & mean level AGC, remember I have been at this for over 40 years, and yes I do feel the dual standard sets we made were UGH! Look at the results some are getting on Pye 11U's now on UHF 625! and not everyone stayed in a fringe area
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