Mechanical Television primer

Mechanical Television primer Author Topic: Mechanical Television primer  (Read 540 times)

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Offline w.mayer

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Mechanical Television primer
Re: Mechanical Television primer
« Reply #13 on: Sun November 26, 2017, 10:11:20 AM »
I think the last picture show the 32 line TV right?
WOW what happen less than 100 years ago and think what we will have in 100 years from now!

Offline albert

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Mechanical Television primer
Re: Mechanical Television primer
« Reply #14 on: Sun November 26, 2017, 10:21:04 AM »
Hi Wolfgang!

The picture was photographed off the rotating disc and according to the caption it shows a business partner of J.L. Baird, Oliver Hutchinson.  So then this would be a 30 line image, the later NBTV "club" standard is 32 lines.
Apparently this picture accompanied the article in the "TIMES" about Baird's successful demonstration for the Royal Society in 1926. Source: The English Wikipedia article on JL Baird.
It is really staggering to think about the development of TV in the past 100 years. We should put one of the rotating disc machines next to your projector one day!
« Last Edit: Sun November 26, 2017, 10:24:13 AM by albert »

Offline w.mayer

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Re: Mechanical Television primer
« Reply #15 on: Sun November 26, 2017, 11:05:14 AM »
I love to do a separate room with some antic stuff inside like the a good CRT Projector an old early Tube TV and if possible some of the stuff you talk about.

I think about it since many years.
But the room I had plan for this is blocked by my daughter for the next years :)

Offline donaldk

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Re: Mechanical Television primer
« Reply #16 on: Sun November 26, 2017, 02:33:46 PM »
That trans Atlantic transmission was actually captured on a record, yup phonogram/-graph became a videograph. Low information content made that it could be captured onto a shellac disc. A number of years ago this disc was decoded using modern computer technology.

http://www.telegraph.co.uk/culture/tvandradio/11898165/John-Logie-Baird-recording-saved-by-anonymous-donor.html
http://www.tvdawn.com/earliest-tv/phonovision-experiments-1927-28/the-recovered-images/


Offline donaldk

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Re: Mechanical Television primer
« Reply #17 on: Sun November 26, 2017, 02:34:50 PM »
Wolfgang, so you already collected a Saba Schauinsland, and a Volksbox?

Offline w.mayer

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Re: Mechanical Television primer
« Reply #18 on: Sun November 26, 2017, 04:10:07 PM »
No I not have it but I may will buy some if I can get a good deal.

Offline albert

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Re: Mechanical Television primer
« Reply #19 on: Mon November 27, 2017, 06:13:50 AM »
Wolfgang- it would be great to have a little museum next to your projection room- but I guess your daughter would not like it!
Donaldk- I'm glad you mentioned the Baird "Phonovision" system, it was the first video recording process, long before AMPEX & co. in the 1950s. A British engineer managed to retrieve the images on these first discs - something Baird himself had never been able to do.
Today, the shellac disc of old has been replaced by the compact disc, and the low band video signals of the Baird process can be recorded on a CD-ROM as an uncompressed wave file. The sound for the video can be recorded on the other audio channel.

Mechanical television is by no means dead today. We will get to it!

The years from 1925 to 1939 were a time of feverish development. What had begun with a 30 line system and wooden discs ended here in Germany (just before the World War interrupted everything) with a fully electronic 441 line system including interlace.
The 2 MHz bandwidth of 441 line tv could not be transmitted on shortwave anymore, so TV helped bring in a new era of what we call FM ukw radio today.
But the Nipkow disc was used way into the fully electronic era, mainly for film scanning purposes. Here the inherent light loss of the Nipkow system could be compensated by using arc lights for the scanning process.
This led to one of the craziest inventions: "Zwischenfilmverfahren" in German.
If you wanted to "televise" an outdoor daylight scene, the Nipkow disc was not useable because of its light loss. So the rather incredible idea was

To film a scene on 35 mm movie film,
run this out of the camera into a super fast developing machine ...
then scan the still wet film with a Nipkow disc scanner.

This whole contraption was built into a big truck with a platform on top where the film camera stood on a hollow pedestal. The exposed film would run thru the pedestal into the truck to be developed and scanned ...and bingo! Here was your "Zwischenfilm " - in-between-film- process.
Below is a design for a 441 line Nipkow disk with several spirals and synchronization holes.
The second image shows the last Fernseh AG scanner built before the war - combined film scanner and a system like a videophone for transmitting images of the "talking head" type- 441 lines with a rotating disc in a vacuum housing. 10.000 rpms! If something goes wrong with such a monster, it's "duck and cover!"
« Last Edit: Mon November 27, 2017, 08:23:52 AM by albert »

Offline donaldk

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Re: Mechanical Television primer
« Reply #20 on: Mon November 27, 2017, 12:40:46 PM »
Indeed (again) Mark Schubin has presentation(s) that include descriptions of this system used at the 1936 Olympics.

Mechanical Television primer

Another little history in English on Fersehen AG http://people.ischool.berkeley.edu/~buckland/television.html

Quote
John Logie Baird began developing the process in 1932, borrowing the idea of Georg Oskar Schubert from his licensees in Germany, where it was demonstrated by Fernseh AG in 1932 and used for broadcasting in 1934.[2] The BBC used Baird's version of the process during the first three months of its then-"high-definition" television service from November 1936 through January 1937,[3] and German television used it during broadcasts of the 1936 Summer Olympics.[4] In both cases, intermediate film cameras alternated with newly introduced direct television cameras.

https://ipfs.io/ipfs/QmXoypizjW3WknFiJnKLwHCnL72vedxjQkDDP1mXWo6uco/wiki/Intermediate_film_system.html (oops originally from wikipedia)

Fernsehkanone for the intermediate film system:

Mechanical Television primer

And for the Telefunke Electronic system (cameraman is Walter Bruch inventor of the PAL-system):

Mechanical Television primer

BTW, this site shows that Fersehen AG has also released at least two CRT TVs.
http://www.tvhistory.tv/1935-1941.htm

A glimpse is available of both the (front) lens to the and an 30 centimeter CRT set by FernSehen AG.



I did not know there were mechnical Television broadcasts here in Holland as well in pre-war. I just knew about the electronic TV experiments, like radio the decade before backed by Philips. http://www.tvhistory.tv/1935-TV-Netherlands.htm
« Last Edit: Mon November 27, 2017, 02:18:56 PM by donaldk »

Offline donaldk

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Re: Mechanical Television primer
« Reply #21 on: Mon November 27, 2017, 02:57:02 PM »
Phonovision:



Offline albert

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Re: Mechanical Television primer
« Reply #22 on: Mon November 27, 2017, 11:42:11 PM »
donaldk, you're faster than a speeding bullet! Thanks for showing these pictures- I was kinda baffled as to how to translate the German "tapeworm" of a word "Zwischenfilmverfahren". Intermediate film...easy.


This documentary shows some of the retrieved footage done with the intermediate film process. Thanks to these images- from about 11 minutes into the film- we can imagine today what the "programs" must have looked like. The documentary can be found under several names - the link I posted had the best image quality but it is in German. If you want to find the English versions google for "Television Under the Swastika".
BTW- the images above show the "TV Cannon " iconoscope camera used during the '36 Olympic Games - the intermediate film camera was much smaller and mounted on a truck - it, too, can be seen in the documentary film.
Fernseh AG became one of the "motors" of television technology- one of it's founding fathers was none other than John Logie Baird. He was disappointed with the BBC and so turned elsewhere to find business partners.
In Pre war times, Fernseh AG was in touch with the American tv developers at RCA . The US lab had trouble finding suitable phosphors for their CRT tube development. The German side  gave them this stuff and in turn received an Iconoscope from Dr. Zworykin. This was quickly duplicated and found its way into the Fernseh-Cannon camera. The other system, Farnsworths Image Dissector tube was also duplicated in Germany. But I digress...we are still "mechanical" at the moment......
« Last Edit: Mon November 27, 2017, 11:43:30 PM by albert »

Offline donaldk

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Re: Mechanical Television primer
« Reply #23 on: Tue November 28, 2017, 04:50:58 AM »
Actually the biggest of the two TV Cannons was the intermediate film one, that one like the electronic iconoscope one it came in a long distance version. At least the sources for those images declare that the long one with the large white box at the end is for the intermediate film process. Those cannons use huge lenses. I showed the intermediate film processing version first, followed by the iconoscope one manned by the PAL inventor. You are refering to the one directly on top of the truck, more or less a regular 35mm (or split 35mm =17.5mm) film camera (Zeiss Ikon?), that was used for capturing from coser distances (wider shots with the long lens ones for close ups, I gather).

Speaking of RCA and CRT (kinescope): Promotional film for the introduction at the 1939 New York World Fair.
« Last Edit: Tue November 28, 2017, 05:03:47 AM by donaldk »

Offline albert

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Re: Mechanical Television primer
« Reply #24 on: Tue November 28, 2017, 06:58:22 AM »
Sorry, donaldk, both of the images you posted show the iconoscope camera. The intermediate camera was much smaller and it came on top of a truck, much like in your drawing. To my knowledge the stationary camera in the stadium did not use the intermediate process. They also had smaller tv cams with the Farnsworth dissector tube - referred to as "Sondenröhre" in the old FERNSEH  AG litterature.
The very large lens diameter of the Olympic Cannon clearly indicates  the iconoscope camera. The target of  the iconoscope was much larger than a 35 mm frame. This accounts for the lens diameter, which would not make sense for an outdoor daylight film camera. The extremely long focal length was needed in the stadium.
I have attached  an image of the "Zwischenfilm" truck.

I refer you to these pages:
http://www.fernsehmuseum.info/walter-bruch.html
Gert Redlich's virtual tv museum is a great source of information. It takes a long time to read thru all of this, though. And its in German...

I'd just love to know how to get images directly into the text .....so far I have not been able to find the trick.
« Last Edit: Tue November 28, 2017, 07:06:17 AM by albert »

Offline donaldk

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Re: Mechanical Television primer
« Reply #25 on: Tue November 28, 2017, 07:28:48 AM »
If they are hosted somewhere online (the dci-forum mediagaller no longer works for me, you might try that to upload images). Type
Code: [Select]
[img]url[/img] and it is shows there.

Iike:

Mechanical Television primer

Or linking a version hosted elsewhere, I found through google:

Mechanical Television primer

« Last Edit: Tue November 28, 2017, 07:40:12 AM by donaldk »