Scanning discs

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Scanning discs

Postby DrZarkov » Sun May 13, 2007 11:35 pm

The well know scanning disc made by this Excel spreadsheet do not have that good result, but I found the program "DiscDesigner" by Sergei Ludanov" (KD6CJI), made for MacOS X. I've made some disks, one in NBTVA-standard withoud synch-holes (ideal for printing on A4 paper to make a simple cardboard-disc), one with synch-holes, and the third in Baird-standard 30 Lines, aspect ratio 3:7, but with synch-holes.

The advantage of those disc is, you can scale them as big as your printer can print them (there are copyshops with A3 and even A1 printers). Ideal for making a cardboard-disc just for testing or for experiments with a PCB-disc. I don't know if a PDF is good enough for a laser cut disc, but I'm afraid not.
Attachments
nbtv-disk1.pdf
NBTV-disc without synch-holes
(4.75 KiB) Downloaded 512 times
nbtv-disc2.pdf
NBTV-disc with synch-holes
(7.09 KiB) Downloaded 481 times
baird-disc.pdf
Baird-disc
(4.58 KiB) Downloaded 495 times
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Postby Klaas Robers » Tue May 15, 2007 2:49 am

Oh oh, how could mechanical TV ever be realised without:

- Laser printers,
- pdf-files
- computer guided laser cutting,
- high brightness LED's
- digital integrated electronics
- CD and CD-R
- modern servo electronics

and isn't there more?
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Postby DrZarkov » Tue May 15, 2007 4:42 am

My very first Nipkow discs I've made with a normal ruler, a pair of compasses, and a geo triangle (is that really the english word?). Why not using modern methods? :)
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Postby Klaas Robers » Tue May 15, 2007 7:42 am

Volker, anyway I know what a "geodriehoek" or "Geodreieck" is. I think you Germans, so close to the Dutch Border use the same Things in die Schule as our Kids op School. But I am going to make a Nipkow disc from your pdf and a kartonnen vlaaienschijf, just to see how large the deviations are and to compare those with the Darvic club disc.

It was just that I wondered already for so long time that we use the most modern components and production methods to show Nipkow TV in a way that was absolutely impossible in the 1930's.
I have here the components of an original Baird Televisor, exept the 30 holes disc, which Denis made me a replica of. I can tell you that the original Neon plate lamp gives so little light that I had to be in absolute darkness to see at least something. At these low light levels the flicker is remarkably less annoying than with my string of high brightness LEDs behind my 32 line Nipkow disc monitor.
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Postby DrZarkov » Tue May 15, 2007 5:59 pm

Maybe the neon-lamp becomes darker over the years? But indeed, I they were much weaker than modern LEDs. My first experiments 25 years ago started with a single yellow LED, a common LED, not an ultra bright one. It is a kind of "peep-show" TV, and maybe you read the comments of Paul Nipkow when he saw his invention working in 1928 at the "Funkausstellung" in Berlin. He was not impressed.
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Postby Dave Moll » Wed May 16, 2007 4:16 am

DrZarkov wrote:a geo triangle (is that really the english word?).

If I am understanding you correctly, the English name for it is a "set square" - though a triangle would be a better name, as its shape is that of a right-angled triangle with the other two vertices at 30 and 60 degrees respectively.
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Postby DrZarkov » Wed May 16, 2007 4:38 am

" Set square", aha! :D
I didn't found the word in the dictionary, Google translated "Geodreieck" with "geo triangle" and I knew the dutch word is "geo driehoek", so it didn't seem such to be a stupid translation. :wink:
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