NBTV Test - 1920s-Style TV

Testing a setup for displaying mechanical 60-line TV signals on an oscilloscope screen. A new 12.5Hz (yes, it's that slow!!!) multivibrator needs to be constructed, as well as a circuit for inverting the sync-positive output "audio" signal from the computer. The oscilloscope will provide the 750Hz line sweep via its external sync input. Vertical retrace blanking cannot be easily achieved with this setup.
I hope to record the the low-band video signal along with program audio onto a stereo cassette or 1/4" reel-to-reel tape. With this video converter, I can record 32 or 60 line video directly to my hard drive. I can also record directly to an external audio recording device like a digital recorder or tape machine.
Link for the website in the video:
http://users.tpg.com.au/users/gmillard/nbtv/nbtv.htm

Category:

Science & Technology

Tags:

• mechanical
• television
• baird
• televisor
• 1930s
• 32
• 60
• lines
• raster
• scanning
• nbtv
• vintage
• electronics
• video
• scan
• conversion
• audio
• signal
• narrow-band

[jrcstudios]

Now you have to build a true mechanical TV as a reference.. I've always wanted to do that..

[CameramanLink]

@jrcstudios I would build a camera as well, but I have no idea how to build the Nipkow disc. How do you make sure all the holes are exactly in the right place, the right width apart, and will scan the entire field of view without going above or below? How do you keep the motors in sync with the vertical retrace pulses, or the holes flying by in time with the horizontal pulses? This sounds like some tough stuff to build for someone inexperienced with building mechanical stuff!

[AllAmericanFiveRadio]

Nice experimenting! You are going to be surprised what knowledge you will use in the future. The rules are always the same but why you need them keep changing.

[CameramanLink]

@AllAmericanFiveRadio I haven't done any experimenting in a while, and all of a sudden I got the urge. I never get tired of this stuff, and I feel that I've learned a lot in my 10+ years of tinkering and doing stuff like this.

[wattmeter]

very cool.

[CameramanLink]

@wattmeter Thanks!

[computersolutions164]

@CameramanLink There are templates for Nipkow disks all over the web, which you can use as a pattern

[EmperorOfMars]

@CameramanLink I can help you with that. Try using the same nipkow disk for recording and playing the video. You have to delay the signal on the way to the viewing screen but I'm sure you can figure that out. As for everything else. Just google it

[ufoengines]

Neat! Have you Narrow Band TV folks seen the youtubes that the builders of RGB Clocks, or Propeller Clocks have posted? Seem to be right up you guys alley.

Making a fan into a tv screen seems like a really cool gimic!

[albionrulesok]

@CameramanLink Circuits are available for synchronising the motor which are definitely no more complex than what you are building here (congrats on that by the way) - in fact the circuit I usually use is little more than a bistable and a power transistor (or tube). Again these circuits are readily available the the NBTVA. Alternatively you can use a synchronous motor like a bicycle dynamo or even a stepper motor.

You have a very interesting channel - keep up the great work!

[albionrulesok]

@CameramanLink It is not too difficult to build your own Nipkow disk, the accuracy will depend on your construction skills, what equipment you have, if you build jigs etc, but a passable disk can be built by printing out an image of one on a laser printer and gluing that image on cardboard or thin plastic or metal, and then drilling or punching the holes according to the image. Accurate laser cut disks can be obtained from the Narrow Band Television Association (NBTVA), at reasonable prices.

[CassetteMaster]

I downloaded this, and hooked the output of the sound card to the video input on a late 70s Sony monitor, but I get a bunch of moving white and black horizontal bars. How might I make it work?

[CassetteMaster]

So it I downloaded the program, could I put the soundcard output directly to a video input of a regular video monitor? Or does it have to be put through the special setup you built? I'd like to try that program and make some videos on audio cassettes and other tape formats. --Imagine-- A video 8-track tape cartridge!

[AllAmericanFiveRadio]

@CameramanLink

Oh I understand, every old radio I work on is different. The more you look, the more you see something new. I have told many friends that if I get bored, it's my fault.