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old TV - *really* old

N

NutmegCT

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Connecticut
If anyone's interested, last year I decided to "build" a mechanical television, based on the work of John Logie Baird (Scotland) in the late 1920s.

Fully mechanical scanning (Nipkow disc) with photocell at the camera and LED (couldn't find a usable neon bulb) at the receiver. Synchronized Nipkow discs provided the line scanning.

Here's a link to my original post on another forum:

http://www.britishcarforum.com/bcforum/ubbthreads.php/ubb/showflat/Number/390735/

I've been "into" old tech since I first built a mechanical TV back in 1965 when I was in highschool. Found the instructions in a 1927 issue of Science Newsletter.

What's the picture look like?

w03.gif


Tom
 
Pretty cool, Tom! I'll bet an LED will handle a lot more bandwidth than a neon, anyway.

Before FAX machines, there were flying spot scanners, where the object to be sent was illuminated by a raster scanned on a regular CRT and the reflected or transmitted light (depending on the setup) was intercepted by a phototube or photomultiplier. It used to be a niche area in amateur radio when iconoscopes or image orthicons (later vidicons) were way outside the budget of a mere human.

When I was a kid in high school, I got to meet Vladimir Zworykin. A very nice gentleman.

If I look at the images from the tvdawn website, the scan direction seems to be top to bottom (or bottom to top) rather than from side to side. Do you know the reason for this?
 
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I know I'm not being very informative, :) but there is an old German fellow living next to me whom I believe is a grandson of the original Nipkov. This eccentric man is up all night working on stuff so it would appear that there is a certain gene carried forward.

Edit: I just talked with "Eberhardt" and confirmed that he is indeed the grandson. His father's name was Paul Nipkov Jr.
 
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Chuck(G) said:
If I look at the images from the tvdawn website, the scan direction seems to be top to bottom (or bottom to top) rather than from side to side. Do you know the reason for this?
Click to expand...

Chuck, the British scanning "standard" originally set by Baird and the BBC was a vertical scan. The viewing area was on the right side of the spinning disk, at the "3pm" point; thus the lines were vertical.

Many European and American systems used the same type Nipkow disc, but set the viewing area at the top (12 noon) point, so the spinning disc in effect created horizontal lines.

Note this 1932 Russian "televisor", which allowed vertical scanning (right side) and horizontal (top) scanning.

1932-Russian-TV.jpg
 
Now there's a cultural difference! You need fewer scanlines with vertical scan for portrait (Baird's blistered assistant) or horizontal scan for landscape (wide open spaces). fewer scanlines means fewer holes in the disc, and less of a problem with sync.
I suppose the vertical came first because of the problems of illuminating a large area sufficiently, unless you have a handy desert full of cowboys, indians and Elvis. :cool:
 
Ole Juul said:
I know I'm not being very informative, :) but there is an old German fellow living next to me whom I believe is a grandson of the original Nipkov. This eccentric man is up all night working on stuff so it would appear that there is a certain gene carried forward.

Edit: I just talked with "Eberhardt" and confirmed that he is indeed the grandson. His father's name was Paul Nipkov Jr.
Click to expand...

Definitely cool! What kind of things is your neighbor working on? Does he by any chance have any items that his grandfather worked on?

Germany's first public television channel, started in Berlin in 1935, was named "Fernsehsender [television broadcaster] Paul Nipkow".

Edit: here's a link to an early "very official" German broadcast, using the relatively new fully-electronic system:

http://www.youtube.com/watch?v=LeYDyf8krYM

Thanks for the update.
Tom
 
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I just picked up an inventory of old Radio & TV books, parts, etc from the 30's. Sam's, Rider, National Union, etc. I'm fascinated by it all. I can research just about any TV, Radio or Phonograph now. Best hundred bucks I ever spent. I did not know about mechanical TV's until now.
 
I used to have a small collection of just-prewar handbooks ("The Radio Handbook", ARRL RAH, etc.). I got a kick out of the prewar television ads, such as this one for a Meissner. The interesting thing is that, but for modern times, the cost of a consumer-level TV has run somewhere around $200 for as long as I can recall.

Looking at the Meissner chassis makes me long for a PC in a real black crackle-finish case. Does anyone even do crackle finishes anymore or is it a lost art?
 
Great job! My old books call it "crackle" but I see that the more prevalent usage today seems to be "wrinkle". Live long enough and everything you know will be wrong... :(

My old ARRL handbook has a DIY version by spraying with a coat of clear Duco lacquer (the old nitrocellulose kind, not the modern urethane), letting it dry and then spraying a paint color coat and "wrinkling/crackling" in an oven. I did this once and got a very nice deep-texture job, not at all like the old Krylon "wrinkle" paint, which has a much finer, shallower appearance. Fortunately, it's still possible to get nitrocellulose lacquer.

Now to get some old jeweled indicator lamps and bakelite knobs...
 
Chuck(G) said:
Great job! My old books call it "crackle" but I see that the more prevalent usage today seems to be "wrinkle". Live long enough and everything you know will be wrong... :(

...

Now to get some old jeweled indicator lamps and bakelite knobs...
Click to expand...

Boy do I hear you on that "everything you know will be wrong". But wait a while and it'll all be useful!

Now if I may veer off the vintage computer course a bit - here's my vintage carriage. A 1959 Triumph TR3, rolled off the line in Coventry England in April 1959, arrived in Portland Oregon in October, on the ship Star of Canada. Three years ago I became its "guardian". I've tried to bring it back to the condition of "one owner car, well driven, and well cared for." And definitely not a "trailer queen". There's even a few blemishes in the panel's black wrinkle finish.

Really love this car, driving our twisty two-lane blacktops here in New England.

Edit: for some reason I can't insert the image. Just shows as a blue question mark, so I'll have to attach it.
 

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Very nice ride! Old British cars hold a certain design fascination, don't they?

I have a friend who probably still has an MG TC sitting in his garage that he's been meaning to get 'round to for the last 30 years or so...
 
You're allowed to go O/T in theO/T section!
This message has been sitting here all day, so it may well have been answered already, but plasticote do crackle & wrinkle paint, and if you do a search on amazon or suchlike, there are other manufacturers.
 
nige the hippy said:
This message has been sitting here all day, so it may well have been answered already, but plasticote do crackle & wrinkle paint, and if you do a search on amazon or suchlike, there are other manufacturers.
Click to expand...

It's been my experience that there are limits to what you can do with rattle-can paint--and I know very little about Plastikote. For lacquer, I like to use Nikolas or VHT; for paint, Sherwin-Williams or DuPont are pretty good. Both applied with a spray gun. For a finish with depth, you can't beat real lacquer.
 
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