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Old 26th Mar 2010, 3:40 pm   #1
practical
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Default "SECAM has 819 lines"

In the early 1980's my friend told me that a teacher at his engineering college had taught him that there were three television systems. Outside of PAL, which we used, they were NTSC, the American system, and SECAM, the French system. Among other differences, PAL had 625 lines, NTSC 525, and SECAM 819.

I thought this was a gross oversimplification because it didn't account for the use of SECAM with a 625 line system in Eastern Europe and the Middle East, or PAL with a 525 line system in Brazil.

Of course, for at least 30 years, SECAM has also been used in a 625-line environment in France itself. I am even beginning to wonder to which extent SECAM was ever used with 819 line systems in France (or Belgium, Luxembourg, or Monaco for that matter) before the 819 line system was retired. I once saw a French 819 line TV set, but it was b/w, and I suspect that even if 819-line SECAM transmissions ever took place, it might have been before color receivers became widespread.

Also, of importance to program exchange with other countries, I would suspect that at some point (1960s-70s?) television production in France would have taken place in a 625 line environment, with 819 line transmissions being a result of up-conversion. Thus French programming would only need transcoding, not line conversion, when passed on to other 625-line countries.

Can anybody enlighten me?
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Old 26th Mar 2010, 4:00 pm   #2
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Default Re: "SECAM has 819 lines"

SECAM on 819 is news to me! I am pretty sure (99%) that SECAM was never used on 819 lines in France or elsewhere.

By the way, don't forget Middle East SECAM as a colour standard - used on Systems B/G there.
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Old 26th Mar 2010, 4:07 pm   #3
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Default Re: "SECAM has 819 lines"

AFAIK, SECAM was only ever used in 625 as a real service. ABC (predecessor of Thames TV) may well have done 405 SECAM experiments in the early 1960s.

PAL is mainly 625 but Brazil used a properly engineered 525 line PAL. Other south american countries have used oddball PAL systems with 625 lines and a lower frequency subcarrier. This was only for transmission. The studios always used ordinary PAL with 4.43MHz SC. Again ABC may have done 405 PAL experiments.

NTSC has only ever seen service on 525. It was tried experimentally by the BBC and others in the UK on both 405 and 625.

AFAIK no colour work was ever done on 819. I could be wrong.

As SteveCG points out, there are several variants within each basic standard but these apply mainly to the transmitted signal rather than the video baseband. The main exception is SECAM-H, as used in the middle east, which doesn't have the "bottles" in the VBI to sync the Db/Dr sequence.
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Old 26th Mar 2010, 9:47 pm   #4
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Default Re: "SECAM has 819 lines"

Certainly, when France had 819-line mono, its SÉCAM colour service was 625-lines. This is borne out by the dual-standard set which I have, designed for those two standards.
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Old 26th Mar 2010, 10:40 pm   #5
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Default Re: "SECAM has 819 lines"

819 Lines / SECAM was tried in the lab, but it wasn't all that good. So it never made it out of the labs. Unlike 405 Line NTSC, which was but other forces intervened.

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Old 28th Mar 2010, 1:35 am   #6
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Default Re: "SECAM has 819 lines"

I think that there has been an element of over-simplification in general, non-technical public usage, in that colour systems have at times been used to refer to whole television systems, and not just the colour part. Hence there is a strong association between NTSC and 525 lines, and between PAL and 625 lines. Possibly the knowledge that SECAM was of French origin, and that the 819-line system was also French led to the false conclusion that SECAM was associated with 819 lines.

As perhaps an extreme example of this over-simplification process, Radio Shack in the USA referred to (and probably still refers to) Belling & Lee 75 ohm coaxial antenna connectors, much used in the UK, Australia, New Zealand and South Africa and probably elsewhere, as “PAL connectors”. Given that F connectors were/are standard in the USA, presumably the Belling & Lee type were associated with UK/European imported products, and were so thought to be a facet of the PAL television systems used there.

Re SECAM development, I think this started around 1955. So I would imagine that soon thereafter would have been the first murmurings of the inexorable move to 625 lines. It seems that during the second half of the 1950s, the various European broadcasting authorities were individually and collectively looking at UHF TV broadcasting and colour systems, and were stepping towards a common UHF 8 MHz channelling system, albeit ultimately to accommodate a whole plethora of 625-line transmission standards. So I would guess that SECAM development quickly moved to 625 lines, which work in any event would have been necessary to allow its export to other countries. Quite probably there were debates within the French industry and institutions about whether both UHF transmissions and colour transmissions should be 819 or 625 lines, much as there was a similar debate – with late rearguard elements - in the UK about 405 and 625 lines. One difference in France, though, seems to have been that with the large bandwidth appetite of the 819-line system, moving to UHF was essential for the second national program, whereas in the UK two were accommodated in the VHF channels, with the possibility that a third might have been shoe-horned in.

Interestingly, Carnt & Townsend, which across the two volumes I think provides about the most comprehensive general coverage of European colour TV developments through to the late 1960s, seems not to mention 819 lines in connection with the SECAM system.

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Old 28th Mar 2010, 9:14 pm   #7
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Default Re: "SECAM has 819 lines"

Quote:
Originally Posted by Synchrodyne View Post
Radio Shack in the USA referred to (and probably still refers to) Belling & Lee 75 ohm coaxial antenna connectors (...) as “PAL connectors”.
What some refer to as the Belling & Lee 75 ohm coaxial antenna connectors, in Denmark we called "IEC connectors". I was not aware that they have any other name. I wonder it it is only in the British Commonwealth that they are known under the name Belling & Lee.

Last I bought IEC to F-type converters from RadioShack about 4 years ago, they were still called "PAL connectors". Their part numbers are 278-265B and 278-261 depending on whether the IEC end is male or female. I do not remember which is male and which is female. The RadioShack web site did not provide any guidance as to which was which or what applications they are appropriate for (TV and radio use opposite gender allocations).
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Old 28th Mar 2010, 9:25 pm   #8
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Default Re: "SECAM has 819 lines"

Paging Kat Manton - owner, I believe of an 819 line set!
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Old 28th Mar 2010, 9:51 pm   #9
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Default Re: "SECAM has 819 lines"

Hi.
I have had a few 819 line sets through my hands. I believe that the "teacher" in post 1
possibly may have read into SECAM wrongly. I would think he has used the term loosly and tied it to 819 line sets. 819 and 405 have more in common than 625 & PAL, both 819 & 405 have positive video modulation and AM sound and its possible that the "teacher" had confused the positive video & AM sound with SECAM which is possible if he didn't fully understand the systems.
819 was really doomed from the start, to attain the full bandwidth at least one extra vision IF amp was required in the receiver and if the full 11mhz bandwidth was used there really wouldn't have been many channels on VHF, of course UHF would have been ideal for full bandwidth 819 but this didn't happen.
Proper full bandwidth 819 & SECAM would have been execptional but equipment limitations put paid to that, one reason why 405 line NTSC was so good, it was right for the time.

I have searched and find no reference to colour experiments on 819, my sentence above is conjecture, if done correctly it "would have been good".
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Old 29th Mar 2010, 2:34 pm   #10
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Default Re: "SECAM has 819 lines"

I would think that our lecturer chap has confused SECAM (the French colour system) with SCART (the French standards authority). Similar confusion occurs, but in reverse, with NTSC, which is the US standards authority, not the colour system.
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Old 29th Mar 2010, 5:48 pm   #11
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Default Re: "SECAM has 819 lines"

I agree that NTSC is the name of the standards body, but what then is the correct name for the system?
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Old 29th Mar 2010, 6:03 pm   #12
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Default Re: "SECAM has 819 lines"

Quote:
Originally Posted by Station X View Post
I agree that NTSC is the name of the standards body, but what then is the correct name for the system?
broadcast system M? ( or it was in analogue days)
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Old 29th Mar 2010, 11:42 pm   #13
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Default Re: "SECAM has 819 lines"

I think this was a case where the standards committee name (NTSC) was also adopted for the system name. Interestingly Fink (1957) does refer to the NTSC system at times, but more often to the “American Color System” and sometimes to the “American Compatible Color System”. It would seem that NTSC’s broader role as a standards development and setting body has been overshadowed by its rather monumental effort in developing the American color system, such that there is now an indelible association. I am not sure, but I think that it may also have been the NTSC that established the American monochrome TV standards (525/60) in 1941.

The System M designation comes from the CCIR, not the NTSC. See the concurrent thread: https://www.vintage-radio.net/forum/...ad.php?t=52088.

Also, the letter designations refer only to the underlying monochrome transmission standard. As far as I know designations such as M-NTSC were also later added to the CCIR terminology.

Cheers,
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Old 30th Mar 2010, 1:24 pm   #14
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Default Re: "SECAM has 819 lines"

I have grave doubts whether a suitable shadowmask tube would have been available to display secam at it's theoretical best on the 819 line system, at least not for public use at an affordable price back in the 1960s. Equal vertical and horizontal resolution being the name of the game would make 625 lines an obvious choice. I conjecture that the 819 line system was the result of misguided national pride.Whilst visiting France (quite often) in the 60s I dont think I ever saw a domestic set with the full 10.5 MHz. video bandwidth.

"Pal a variant of the N.T.S.C. Colour Television System", by Dr. Walter Bruch gives an excellent insight into all the three colour systems used and a system originally developed by the B.B.C. in the 50s using 405 lines and then taken up by the Russians in the 60s on 625 lines. NIR was the name of the system, Q.A.M. was transmitted on alternate lines and a fixed phase reference transmitted on the other lines . Simultaneous colour difference signals were then re formed by the use of a delay line to enable reference and chroma to be available on all lines, albeit with reduced vertical chroma resolution as with P.A.L. and secam. It's advantage was that it did not need a local reference osc It had quite a few problems and never saw service outside the lab except for a series of test transmissions. It's main problem was that any noise on the received reference signal was added to the noise received on the chroma signal. Diff phase and gain errors however tended to track the chroma signal. Compatability with monochrome was also rather iffy.
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Last edited by ENGLISH VICTOR; 30th Mar 2010 at 1:35 pm.
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Old 30th Mar 2010, 5:06 pm   #15
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Default Re: "SECAM has 819 lines"

Quote:
Originally Posted by Brigham View Post
I would think that our lecturer chap has confused SECAM (the French colour system) with SCART (the French standards authority). Similar confusion occurs, but in reverse, with NTSC, which is the US standards authority, not the colour system.
Was SCART actually involved in promulgating the French TV broadcast and color standards? I tried to research the history of SCART on the Internet but there is almost nothing about them except as the originator of the Peritel interface. It appears SCART (Syndicat des Constructeurs d'Appareils Radiorécepteurs et Téléviseurs) has been superseded by SIMAVELEC (Syndicat des industries de matériels audiovisuels électroniques) sometime in the 1980's, possibly as a reflection of the cessation of French domestic electronics production.

It is my understanding NTSC is the name used for two different ad-hoc committees, one in the early 1940s that defined the 525-line monochrome system, and another in the early 1950's that modified that system slightly (frame rate down from 30 to 29.97) while adding a monochrome compatible color system. Since NTSC to my knowledge has not defined any standards other than these two systems, the second of which superseded the first, I can't think of any better name than "NTSC" for the United States, FCC-sanctioned color system. Or maybe "NTSC-color" as opposed to "NTSC-monochrome".

Referring to the US system as "System M" or "NTSC-M" is a bit of an anachronism, as the letter M was not assigned to the 525-line transmission system until many years after its development, and by an international body, not its originators.
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Old 30th Mar 2010, 11:23 pm   #16
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Default Re: "SECAM has 819 lines"

The SCART plug was developed because of something to do with SECAM causing streaky lines on captions IIRC -but maybe wrong.

Meanwhile when Britain was deciding what color system to adopt, here is a
look of what might have been - NTSC on brit 405 lines .
The British TV impressario Lew Grade was very keen to adopt NTSC asap

http://www.youtube.com/watch?v=JVmCKxDyDJs


looks pretty good
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Old 31st Mar 2010, 3:35 am   #17
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Default Re: "SECAM has 819 lines"

Quote:
Originally Posted by practical743

It is my understanding NTSC is the name used for two different ad-hoc committees, one in the early 1940s that defined the 525-line monochrome system, and another in the early 1950's that modified that system slightly (frame rate down from 30 to 29.97) while adding a monochrome compatible color system.
It hadn’t occurred to me that the NTSC was an ad hoc committee – in fact two ad hoc committees. But now that you mention it, it seems logical and consistent with US practice, other such examples (and their outputs) being NSRC (GE-Zenith FM Stereo radio ystem), NAMSRC (no decision on AM stereo), BTSC (MTS TV sound). The NRSC (AM pre-emphasis and band-limiting curve inter alia) seems still to be active.

Cheers,

Last edited by Station X; 31st Mar 2010 at 8:38 am. Reason: quote fixed.
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Old 31st Mar 2010, 7:58 pm   #18
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Default Re: "SECAM has 819 lines"

Check out these abstracts about "the two NTSC's". If interested in the articles, PM me.

http://ieeexplore.ieee.org/xpl/freea...rnumber=784248

http://ieeexplore.ieee.org/xpl/freea...rnumber=784250
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Old 1st Apr 2010, 3:08 pm   #19
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Default Re: "SECAM has 819 lines"

Sorry that the link I posted did not connect with the abstract, although it is publicly available (the other paper is an editorial comment that does not have an abstract). Here is the abstract of Fink DG: "Perspectives on television: The role played by the two NTSC's in preparing television service for the American public"

This paper recounts the adventures of the two National Television System Committees (NTSC's) in preparing monochrome and color television service for the American public. The first NTSC had the active encouragement of the Federal Communications Commission (FCC). Building on the important prior work of the Television Standards and Allocations Committees of the trade association of the time, the Radio Manufacturers Association, it was able to complete its task of setting up the system standards for black-and-white television in less than nine months, from July 1940 to March 1941. These standards, with narrower tolerances but otherwise unchanged, now serve as the basis for the compatible color service now universally broadcast to the American people. The second NTSC had a rougher road to follow. The FCC, having approved an incompatible color system over strong-and strongly resented-objections of the industry's engineers, did not welcome the formation of the second NTSC. The second NTSC had, in addition to these political and institutional pressures, a very difficult technical task, one thought by many at the time to be flatly impossible: to impose high-quality color on the black and white system without injuring reception on black-and-white receivers. Combining and refining the work of many contributors, the second NTSC cogitated and tested from early 1950 to mid-1953 until it had the system we now enjoy-one that has been adopted in its essentials throughout the World. One aim of the paper is to reveal the constructive forces that led to these successes, and the near misses with defeat that were encountered on the way.
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Old 1st Apr 2010, 3:23 pm   #20
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Default Re: "SECAM has 819 lines"

Sometimes, e.g. on video equipment spec sheets, one sees the US standard referred to as EIA/NTSC, for TV system and color standard, respectively. The European equivalent is given as CCIR/PAL.

What has been the role of EIA in setting TV standards? Haven't the standards been promulgated by the FCC based on input from the two NTSC's, and later BTSC (with regard to MTS stereophonic sound)?

Although "NTSC" might have been a possible moniker for the monochrome 525-line standard in the period 1941-1953, was this a common usage at the time? Or was it referred to as "the American system", EIA, or something else?
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