Re: CRTs on Ebay


Don Black <donald_black@...>
 

Hello Michael,
                    I agree with all you say, I'm aware that NTSC is the standards committee rather than the colour standard but NTSC is what the colour standard has become known as (at least outside the US).
I take your point about the US colour standard being capable of good results if all is well, however if you haven't experienced the two systems in operation you don't know just how much "hardier" and more stable the PAL system is. It takes truly awful reception to notice hue changes with PAL.
As I said, I have great respect for the development of the NTSC colour system , the fact it remained in use for so long speaks volumes.

Don Black.

On 13-Jan-14 10:49 AM, Michael A. Terrell wrote:
 

Don Black wrote:
>
> Thanks Craig, interesting comments. Actually I'm in Australia but
> worked on some C1958 Marconi prototype colour equipment. Very useful
> experience. The PAL is rock solid by comparison.
> Our colour service started in March 1975 using PAL. For a few years
> before that a few of us were watching some colour programs from tapes
> from the UK and England. The local signal processors stripped off all
> the colour burst used to lock the chroma circuits but with PAL you can
> recover lock signals from the chroma which wasn't filtered out.
> Philips hawked some prototype sets around the trade in the late
> sixties (trying to push colour introduction I think) and included a
> little chroma lock board to allow users to watch the program. It
> recovered the lock signal and just injected it into the chroma
> oscillator as a trigger but apart from just managing lock on a stable
> signal generator I never saw it successfully lock to an off-air
> program (It might have worked on a properly stabilised program?). I
> thought it would be better with an AFC phase locked loop and built up
> a few boards using it. They worked far better than I hoped and would
> always lock solidly to the weakest chroma. The quality off the tapes
> varied from excellent to colour snow but it always locked right up. So
> for a few years we watched just about anything that moved in colour.
> I've still got a board kicking around somewhere.
> I believe when they were developing what became he NTSC colour system
> in the US it was suggested it would be advantageous to switch one
> colour signal phase on alternative lines (same as PAL) but it wasn't
> considered worth it and didn't happen. The one line delay line really
> makes the PAL system and I guess there wouldn't have been a cheap 64µs
> delay line available. It was the development of the acoustic glass
> delay line that really made it viable. The same delay was later used
> in VCRs for dropout compensation. There is still some advantage of the
> PAL system without a delay line, the eye averages the colour errors
> but gives the Venetian blind effect.
>
> Don Black.
>
> On 13-Jan-14 12:36 AM, Craig Sawyers wrote:
>>
>> =====================
>> Have you ever worked with old NTSC gear Craig. Capable of good
>> results but
>> Never Twice Same Colour oh so true, especially compared to the
>> stability of
>> PAL.
>> Still a great development for its time which served well for over half a
>> Century.
>> Don Black.
>> =====================
>>
>> No Don - but worked quite a bit in the States at one point, and suffered
>> NTSC with arbitrary colours in hotel rooms many a time.
>>
>> That was the big advantage in the UK of being second instead of first in
>> analogue colour television, and PAL was devised to work around the phase
>> distortion colour artefacts of NTSC.
>>
>> There used to be similar acronyms for PAL and SECAM too.
>>
>> Oh yes here we are (google is your friend)
>>
>> SECAM - System Essentially Contrary to the American Method
>> PAL - Perfect At Last
>>
>> I don't know what digital TV is like in the US, but in the UK the only
>> complaint is that the audio level varies over very wide limits from
>> channel
>> to channel. Set it correctly for on channel and you can be near deafened
>> when swapping to another channel. That was never the case with
>> analogue TV,
>> which like FM radio had a dynamic range the led to fairly standard audio
>> levels, with the only exception being adverts which were (and still are)
>> compressed so that the perceived audio level is louder than the
>> programme.
>>
>> Craig
>>

NTSC had nothing to do with color. The 'National Television
Standards Committee' was created to select the monochrome standard, then
years later they worked to add color without abandoning the existing
monochrome televisions and transmitters. There was nothing wrong with
the clor standard. The problem was with network feeds, or stations that
didn't maintain their equipment properly. The networks were fed with
leased bandwidth over the AT&T microwave network, where any Bellcore
tech could screw with the chroma level or phase at any microwave tower.
VIR & VITS were added which eliminated that problem. The US is much
bigger than the UK, with stations scattered all over the nation, unlike
the UK with centralized transmitters.

If you saw a crappy image in a hotel, it was because they bought the
cheapest TVs they could find, and wouldn't have them repaired if they
got any picture at all. I was a TV broadcast engineer, and once
installed the video & RF wiring in a new motel while in the industrial
electronics business.

People would do the same. New color TV on sale for $149 would sell
out in hours, even if the chroma wasn't aligned properly at the Asian
factory. They wuld complain thatthe color wasn't right, after a new CRT
was installed, because they were so used to crap from a dying CRT. One
customer had the chroma wide open, making everything look like a cheap
comic book. He took a swig of cheap beer and said, "If I'm a payin' fer
color, Is gett'n my money's worth". You can't fix stupid.





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