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Old 15th May 2018, 10:23 am   #41
dave walsh
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Default Re: TV system differences?

Blimey Synchrodyne, I thought you were going to say "so I shall be brief" but you have indeed taken a different approach and I found your antipodean overview very interesting indeed, especially the comments about transfer quality [Granada TV was my Region at the time-they were very innovative]. It will be nice to hear what the OP has to say from his part of the world, what he was after in the first place and how the Redifussion system came into being in his location?

Re Brigham's comment [at p40*] I've mentioned elsewhere, the BBC [1966?] viewer trial, reported in Wireless World, when the Beeb compared 405/625 images for the government. They said that 625 lines came out better. I didn't read it then but even I can see it's inaccurate. Most audience members reported little difference but the experts said otherwise. There may well have been political forces at work though, in terms of a possible European 625 line market.
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Old 15th May 2018, 11:18 am   #42
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Default Re: TV system differences?

In fact both 525/60 and 625/50 live on into the digital era - SD services in the respective territories continue to use them

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Old 15th May 2018, 6:08 pm   #43
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Domestic TVs were not capable of displaying 625 line analogue transmissions at their full resolution. I remember reading an editorial in "Wireless World " in the early 1990's titled something like "Who needs HDTV?" pointed out that the crt's of consumer TVs were only capable of displaying about half of the horizontal line information of a 625 line broadcast, the exception being some JVC models that had a 50% finer colour stripe width. Mention was made of a BBC demonstration of HDTV to some of their executives where one had commented on the picture quality, and that that this was the way of the future, only to be told that the demo hadn't started and he was actually watching a properly set-up 625 line studio monitor. Apparently this was one reason why people were satisfied with VHS VCRs that only recorded half the horizontal information: on the typical TV you couldn' tell the difference between live and recording. The only time I could see any difference between live, VHS, and SVHS was when I borrowed a video projector from work and tried it out at home on my matt cine projector screen (3' x 4', giving a 60" diagonal), using the S- video outputs of the TV and SVHS recorders. With this size of picture, the differences could be seen.

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Old 16th May 2018, 1:36 pm   #44
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Default Re: TV system differences?

In the early 1990s there were a few analogue HDTV systems trials, IIRC one was 1250 lines that was backwards compatible with 625 lines SD.

This reminds me of when I bought a tubed Philips 21" TV in 2001 along with a Pace On Digital box. My Dad was impressed with the picture quality, thinking it was a digital signal when in fact it was just the analogue!
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Old 16th May 2018, 2:28 pm   #45
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Sadly that was usually the case. Problem was some areas had cabled systems with 625 at VHF (Stevenage was one), and blocks of flats were often like this as well. I had an argument with Philips over this when I wanted a set for such a situation. Didn't help though and I had to source a set from a continental manufacturer. Towards the end of the analogue era manufacturers, including Philips, started fitting all band tuners and still do to this day (except Panasonic).
Very interesting, and very strange given that Philips were marketing standard all-band and VHF/UHF equipped sets in Ireland from the 60s onwards - what era are we talking about?

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Old 16th May 2018, 4:04 pm   #46
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Originally Posted by Richard_FM View Post
In the early 1990s there were a few analogue HDTV systems trials, IIRC one was 1250 lines that was backwards compatible with 625 lines SD.

This reminds me of when I bought a tubed Philips 21" TV in 2001 along with a Pace On Digital box. My Dad was impressed with the picture quality, thinking it was a digital signal when in fact it was just the analogue!
Your recollection is spot on - the 1250 line analogue system is near enough identical resolution wise to current 1080i digital - the only downside being the bandwidth occupied

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Old 16th May 2018, 6:19 pm   #47
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Default Re: TV system differences?

Today's HD standards are excellent but for someone born in the age of 12" screens and who now have far from excellent eyesight there really isn't much difference between 405 lines and 240 lines except for the very significant issue of flicker which I think was never acceptable.

My normal television is a 32" LED thing and I can't really tell the difference between 625 and full 1080 HD unless I get up close.

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Old 16th May 2018, 6:34 pm   #48
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I did wonder if any dual standard 625 / 819 line sets were made for the French market.
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Old 16th May 2018, 6:44 pm   #49
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Only dual-standard sets were permitted to be imported into France for AGES.
It was often seen as an industry protection measure.
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Old 16th May 2018, 7:23 pm   #50
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Default Re: TV system differences?

Lots of great posts but the original OP has not come back and his last activity is 13th May when he posted the enquiry.

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Old 16th May 2018, 7:44 pm   #51
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Does that matter?

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Old 16th May 2018, 7:50 pm   #52
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Default Re: TV system differences?

I wasn't ever hopeful Mike-three initial posts and no follow up so far. It's not uncommon but we never get an explanation There is a strong cross reference with the current thread in Forum Announcements "Members Last Activity". I think it would help if we weren't quite so helpful, looked at the history and waited for a response initially [especially on some of the repair enquiries] but not everyone agrees. This is a more [very] general topic so [ironically perhaps] it has inadvertently promoted a very interesting thread anyway, as it doesn't rely on OP participation to progress.

Dave

Crossed posts!
You are right that it doesn't matter in this particular case Peter, for the reason I gave there but it can be very frustrating in other situations you know. Beyond that the simplest overall answer to your question would be that this is a Forum!

Going right back to David's comment about the UK Dual Standard System [post 20*] from this distance it looks like a bit of a dog's breakfast, although interesting in terms of the adaptations that took place at the time. Post War "make do and mend" perhaps! As the main benefit of receiving on 625 lines was to gain BBC2, a lot of detractors couldn't see the point of all the silly intellectualism [Jazz 625, Hendrix and Ringo Starr turning up in the middle of Late Night Line Up etc] and stuck to 405 for as long as they could. There was a similar attitude in 1982 when Ch4 debuted.

Last edited by dave walsh; 16th May 2018 at 8:09 pm.
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Old 16th May 2018, 8:21 pm   #53
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If it wasn't for BBC2 there would probably have been no "Tonight in Person" programmes like the hour-long one featuring Peter, Paul and Mary that has probably had more views of its YouTube incarnation than it had for its original airing.

I have a Schneider 625 line VHF/UHF colour TV inherited from a relative who lived in France, that works with SECAM, European PAL, and UK PAL. I assume the UK PAL capability was for the benefit of those in range of the Channel Islands transmitters.
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Old 16th May 2018, 9:12 pm   #54
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Quote:
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Only dual-standard sets were permitted to be imported into France for AGES.
It was often seen as an industry protection measure.
It crossed my mind that the French developed SECAM as a form of protectionism, rather than use PAL, though it was a little easier to convert for international live events.
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Old 16th May 2018, 9:39 pm   #55
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Default Re: TV system differences?

What an interesting thread!
The one issue that surprises me is how long the 405 network persisted after 625 had been established. Presumably single standard 405 TV's stopped being produced in the mid sixties, but did new dual standard TV's go on beyond 1969 when BBC1 and ITV migrated and went colour?
I seem to remember the 405 channels being treated as the 'core' network by the broadcasters right up to the end - Eg. childrens TV was displaced to BBC2 on budget day so that BBC1 could carry political coverage.

Maybe the robustness of VHF transmission in comparison with the new broadcasts?

The digital switchover was far harsher.
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Old 16th May 2018, 10:11 pm   #56
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Yes, apart from a little gap to fight the Nazis 405 ran from 1936 through to 1984. A real testament to the remarkable vision of its developers.

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Old 16th May 2018, 10:22 pm   #57
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Default Re: TV system differences?

Standards conversion and SECAM was a bit of a joke.

It turned out that SECAM was the very devil to mix and do the usual video tricks to because of the delays needed. So programmes were made in PAL and only at the last stage converted to SECAM for transmission.

Supreme Effort indeed!

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Old 16th May 2018, 11:34 pm   #58
dave walsh
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On reflection, I think that BBC trial I mentioned, may have been about colour on 405 lines [which I do agree was a very durable b+w standard]. You only have to look at the [properly set up] 405 line sets Mike Barker exhibits regularly at Golborne to see how really very good it can be. The erudite comments about loss of definition when a larger screen is used [ie beyond the regular CRT sizes] perhaps go a long way towards answering my frequent question-Why didn't we just go ahead into colour with 405? On the other hand, apart from the international compatibility issue, there would have been no real concept of what future screen sizes might be, at the time, despite Baird's work back in the thirties.

Dave W

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Old 17th May 2018, 12:32 am   #59
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Quote:
Originally Posted by Richard_FM View Post
I did wonder if any dual standard 625 / 819 line sets were made for the French market.
Yes. Apparently that was the normal form for French TV receivers when the 625-line UHF service was introduced in the early 1960s. I’d guess that it was maintained until the 819-line service was duplicated on 625.

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Before then, there were multistandard French TV receivers for the border areas. These generally followed the Belgian precedent, and could receive 625 Systems B and C and 819 Systems E and F, usually with limited channel coverage for System E. There were also one or two that could receive 405 System A in addition to the others listed. When UHF arrived, System L capability was added to the Belgian and French multistandard receivers.

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The French setmakers were thus accustomed to the 625 and 819 combination before it became the norm. The French System L 625-line key parameters of positive modulation and AM sound (without pre-emphasis) were chosen to align with those of System E in order to make easier the design (and cheaper the manufacture) of dual-standard receivers. That choice has sometimes been described as a protectionist measure – perhaps it was, although nowhere have I seen any hard supporting evidence for the assertion - but it also had a good engineering rationale. For the Outré Mer territories, where there was not the precedent of System E transmissions and so no need to consider dual-standard receivers, the French used System K’, which was of the negative/FM type. That fact I think somewhat weakens the protectionist argument, but strengthens the engineering case for the System L choices.

Also in respect of helping dual-standard receiver simplicity, the System L standard IF (32.7 MHz VIF, 39.2 MHz SIF) was chosen to align the sound carrier with that of the System E standard IF (28.05 MHz VIF, 39.2 MHz SIF).


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Old 17th May 2018, 12:34 am   #60
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Evidently French dual-standard receivers go back to the early years – according to this Wireless World item, there were some 441/819-line examples.

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And there were 405/819-line receivers for those viewers who were in range of the Channel Islands transmitters:

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The French were also early with bilingual sound transmission, in 1957 in Algeria:

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