Narrow-Bandwidth Television Association

Have not been active with NBTV for a while, but finally got some free time at hand and build a monitor with 15" disk from club sales. Had to tweak quite a bit with motor control board components to achieve stable sync, but now everything is working and I am pleased with the quality of video monitor displays. Disk is superb! Using a single 5 watt white LED as light source and a piece of a tracing paper as a diffuser. Here is some pictures. I chose horizontal scanning this time and 15 fps scanning speed. To produce video for monitor, I wrote a program that runs on my MacBook Pro. Program can convert live video, movie files, still image files, slideshows to nbtv video in various formats (24, 30, 32, 45,48 lines - 12.5 and 15 fps, horizontal and vertical scan), can add scrolling text in small, medium or large size to the video, also produces some test signals. Just noticed that the picture of monitor is rotated in the post...
Thanks and best regards,
Sergei KD6CJI

Hello Sergeij, the quality of the picture is superb!
About your software for MacOS X: Is it public again? I'm still using your old disc-maker software on my old Mac Mini G4, because there is no better software available for any operating system.

Well, software is not quite finished yet, but of course it will be public. This time there is also an audio on a right channel when playing movie or using camera with microphone. The only caveat is that app runs only on 10.9 as it uses new AVFoundation framework. As for disk designer, I wanted to update software but the project is so old that Xcode would not open it. Guess will have to start almost from scratch when I get to it.

Finally after long delay the project is completed. Here are some pictures.

Very futuristic art-deco! Lovely work!

Thanks Andrew,
I can't take the full credit though as the painting of the case was done by my wife ...

She did a lovely job. I think the original knobs are better though. Look a bit more like bakelite.

What a splendid looking set. Certainly a touch of Western Visionette in the styling.

The white picture is stunning. It never occured to me that a white LED could be modulated at these frequencies. I'd imagined it to be a UV-fluorescent device, like the mercury lamp, with a time lag similar to selenium!

I must have a go at horizontal scanning. Something in the style of the Western 'Empire State' is long overdue.

Wow that thing looks sexy! Definitely wouldn't mind having that in my house

Last week I managed to overdrive and burn the 3 watt white LED and because it was the last one I had I could not replace it. But I had 3 watt RGB LED, so I decided to do some experimentation with color. As I am driving monitor from stereo audio, the simple solution was to modify the program to produce 2 color video. Also I did nor want to build 3 LED drivers and ended up connecting green and blue LED in series and feed them with a mixture of .33 blue + 0.67 green and drive red LED with just red, so I got basically cyan and red (instead of orange). Surprisingly this setup works fairly well, of course it is nor 3 color video, but color rendering is close enough. Also it is interesting to note that color image appears to have better resolution than monochrome (which is of course just a perception). I will post pictures when I'll manage to get good enough shots "to brag about". I think I will leave this NBTV monitor as color one, still have to fit the second board inside the case and reassemble the monitor.

OK here is some pictures from the screen:

And a video clip. By whatever reason camera adds some bluish tint...

..possibly it's trying its best at some form of 'white balance' if WB is set to 'auto'....looking for some green...

...plus some blue LED's do put out a small amount of UV - which again may affect WB...even if WB is set to 'manual'....

Most cameras (of any rupute) have an IR optical filter, few have a UV version too...

Forget 'phone cameras, as useful as a bicycle is to a fish.

Steve A.

Make sense. I suspected UV but have not thought about white balance. Both pictures and videos were shot with iPhone and as far as I know there is no manual setting for WB there, so will try to make some pictures and video with Nikon tonight.

Hello there, nice result with color experiment. But it seems you can get even better results if your monitor will be orange-blue type. I once made a two-color TV too. It was some years ago, but I still remember how much tinkering it took to balance all the tree leds representing a two-colored signal. In my machine, I used three separate amplifiers, one for each led. The green channel was connected to the mixer circuit, it received 50% left and 50% right channel. And I used the orange-blue color system, with the programm provided by Gary. The results can be seen on youtube, sorry for poor quality footage but the colours are pretty accurate.
http://youtu.be/4PbA5Vc0jwQ