Colour NBTV with the Aurora World Converter

[yagosaga]

Hello,

in the last days, I got the daughter-board and the LED array for the Aurora World Converter from Darryl Hock. I upgraded my NBTV monitor with the RGB LED array, and the results are stunning! The actual picture looks much better than on the photos due to some difficulties in getting proper focus with the camera.

Thank you very much, Darryl!

Kind regards,
Eckhard

[Panrock]

Originally Posted by yagosaga

I upgraded my NBTV monitor with the RGB LED array, and the results are stunning!

They certainly are! If seeing this doesn't transform colour NBTV into a 'mass market' hobby here, nothing will!

Well done.

Steve

[matthewhouse]

That is fantastic!! What a great image. If only I had endless spare time...

[murphyv310]

Hi.
Quite amazing, I have never been into these standards but things i am sure will change now.
Brilliant
Trevor

[dominicbeesley]

Looks great...still saving my pennies for one!

Dom

[peter_scott]

Hi Eckhard,

What fabulous results! Is this 30 line?

Peter

[ianm]

This is really interesting! More likely to be 32 line than 30, I'd say.

Here's the link to the Aurora web site:

http://tech-retro.com/Aurora_Design/Home.html

As far as I can tell, colour operations would necessitate use of the World Converter, which for many would be out of reach financially. However, a monochrome system would be much more affordable, as one of the Single Converters can be used. I've got the SCM-01 model here.

[yagosaga]

Hello,

it is a 32 line scanning disk monitor. The Nipkow disk was made by Peter Yanczer from St. Louis, the documentation of the monitor is online on

http://fernsehmuseum.net/mechanical/scanningdisc.htm

The video and sound signal for the monitor is taken from the World Converter like before. The former b/w LED array was unplugged and replaced by the RGB colour LED array, which is directly driven by the World Converter. Is sound so simple, and it is.

Last year, I have bought Darryl's World Converter, since I need it for feeding pre-war tv sets, antique German post-war sets, Sovjet tv sets, converting PAL into SECAM, and so on. When I got the converter, I discovered that it provides an RGB output for mechanical television. On the other hand, I had already the 32 line scanning disk monitor, so I decided to "upgrade" it with colour. The costs of this update were only half of the costs for the Aurora World Converter. And since I have my 50th birthday tomorrow, I thought this would be a nice birthday present for myself

Experimenting with NBTV colour is an extraordinary experience. Yesterday, I saw "Yellow Submarine" in 32 line colour, and the results are very fine. Currently, I am working on a method to video the NBTV colour performance as best as it is possible. It is very difficult. Here is a first example:

http://www.youtube.com/watch?v=L83DAJxuUsU

but note that the original footage contains false and negative colours.

Another project this year will be the assembling of a second NBTV monitor, I want one for b/w and one for colour.

In one of my emails to Darryl, I have suggested a new NBTV 32 line standard with 32 lines horizontally scanned (similar to the antique Mihaly / Telehor standard). I believe that this standard might better fit with today's broadcasting aspect ratios.

Darryl's hardware converter provides an absolutely clean colour RGB signal for mechanical television. I am not sure whether the low-cost converter is ready for an expansion for RGB output. If so, this might be a good source for further experimenting.

Kind regards,
Eckhard

[tubesrule]

What I find amazing with color mechanical is how much more information we perceive. With the color output, you can switch between Orange, White and full RGB on the fly, so it's easy to compare them, and even with these extremely low resolution formats, color makes it appear that there is more resolution than there really is. As you can see at 32 lines the picture conveys a lot of detail, and at about 60 lines, you get an extremely high quality perceived image.

This is also simultaneous color, not sequential color so the color frame rate is the full image frame rate. I believe when Baird experimented with color 30 line, it was sequential which would cause color flicker and fringing much like the CBS sequential mechanical color system.

Darryl

[yagosaga]

Thanks, Darryl, for this excellent explanation.

Here is another attempt to demonstrate the exceptional properties of LD* mechanical colour television:

http://www.youtube.com/watch?v=U511AC7olGc

* LD = Low Definition, i.e. the challenge for HD.

[TubeType]

Great work Eckhard. Good luck with your second NBTV monitor. I'm always impressed when someone demonstrates these primitive concepts of television, especially in colour.

Best wishes,

[yagosaga]

Some more remarks regarding mechanical colour tv: I have compared the colors of Darryl's RGB LED array picture on the Nipkow disk with the colors on a screen of a PAL color tv set, both feed with the same test patterns.

Green of the LEDs seems to be much "deeper" and saturated than the green on the CRT screen, and also red of the LEDs seems to be much "deeper" and saturated than the red on the CRT screen. The LEDs seems to provide a wider gamut than the colors of the CRT.

This obeservation was confirmed by the actual values for the wavelengths of the RGB LEDs of mechanical television:

632nm (red)
523nm (green)
465nm (blue)

This seems to be more similar to the wavelengths of the early NTSC color picture tubes than with PAL (except of blue)

636 to 658nm (red)
523 to 532nm (green)
442 to 452nm (blue)

For comparison PAL/SECAM dominant wavelength:

607nm (red)
552nm (green)
466nm (blue)

In the attachment are the wavelengths for the early wide gamut NTSC tubes 15GP22 and 21AXP22. Note that 1 Angstrom is 1 nm.

Eckhard

[AlanBeckett]

Eckhard,
Shouldn't that be 10 Angstrom is 1 nm?
Alan

[yagosaga]

Of course, correct. 1 Angstrom = 0.1 nm

[dominicbeesley]

Yes, I too have found that LED sources give nice deep colours, as opposed to the quite unreal or washed out colours of some CRTs and many plasma and LCDs that we're all more used to.

Dom

[yagosaga]

Here is an attempt to display the differences. But note that this does not show the real performance since the color space limitations of the camera and of the computer display will reduce some effects.

The picture of the upper half of the photos were taken from the Nipkow disk, the picture of the lower half of the photo from the screen of a PAL TV set.

[dominicbeesley]

I find that taking pictures doesn't always give the right impression where colour is concerned as there can be a big interaction with the wavelengths of the source LEDs and the responses of the CCD's.

Just had a quick look at Carnt & Townsend for the correct? NTSC colours and from the numbers above its probably the green that is most over-saturated. One day I intend to make a colour decoder that can be adjusted for the gamut to produce the most correct colours...one day!

Dom

PS: Thats a very nicely drilled Nipkow you have!

[yagosaga]

Originally Posted by dominicbeesley

PS: Thats a very nicely drilled Nipkow you have!

The Nipkow disk was made by Peter Yanczer. He produces fine and professional lasercut disks for best performance.