Author Topic: Old Video Camera Tubes  (Read 5233 times)

Offline J.A.F.E.

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Old Video Camera Tubes
« on: May 19, 2021, 04:16:55 PM »
I was working in the shed and opened the crate these live in. I thought maybe some would be interested in seeing these while I was poking around.

As a little background TV was developed over a period of time and many things were tried including mechanical TV (youtube has some videos of mechanical systems and the images they produced. For the time it was miraculous but by the standards of even a few years later in the 1940's it was pretty bad). The early work started by about 1905 or so but it was the 20's before anything commercially viable was developed. The work of many was involved including Philo Farnsworth but for the commercial CRT (cathode ray tube) system most sources cite Vladimir Zworkin working for Westinghouse in Pittsburgh, PA as the system that became dominant. Zworkin worked from about 1920 to about 33 developing the system. It required a camera, a receiver and of course the broadcast and receiving radios. It was all developed at once although some work was already in place - radio was worked out, an oscilloscope was already in use and they worked in a similar although much much cruder way than a monochrome CRT. But all that had to be sorted out and adapted to the new technology. It really is a very clever system and color TV was really clever since the FCC mandated that existing B&W sets could receive and display a color signal so consumers would not have to buy new sets. B&W broadcasting uses FM for the image and AM for the sound (and color uses PM [phase modulation] for the color signal).

The camera tube was essentially the reverse of a CRT and I have two early versions of the camera tubes and one from about the 70's or early 80's.

The first one is a very early tube from the late 20's or early 30's called an Iconoscope. Here is an image from the wikipedia article on video camera tubes https://en.wikipedia.org/wiki/Video_camera_tube#Iconoscope of Zworkin holding an Iconoscope.



It doesn't look like much. The main part is a mica target coated to be light sensitive. The scanning electron gun in the neck shoots a beam of electrons at the target and depending if light is falling on that spot or not determines if the circuit is completed or not and so current flows or doesn't flow. One is reproduced on the CRT as light the other as dark - this is basic black and white TV. This one is probably from the early 30's and was hand made.









Development of TV was continuous and very competitive. One of the better replacements was the Image Orthicon tube. It works the same basic way but has much resolution and clarity. It was made from the mid 40's to the late 60's and was also hand made. I have most of the storage tube for it although it has seen better days.



Completing my collection is a Vidicon. The Vidicon is small enough that portable TV cameras were possible. The Iconoscope and Image Orthicon were mounted in huge, heavy, power hungry cameras usually mounted on wheeled dollies. Early color systems used three tubes one each for the three primaries red, blue and green.



Comparison of the three tubes to show size.



The Image Orthicon vs a cell phone camera. These tube cameras used in analog systems used a maximum scan rate of 525 lines. The image was dissected vertically into 525 lines and the electron gun scanned one line at a time to break down the image at the camera end and reconstruct the image at the receiver end. That was the maximum though. There were retrace scans and other overhead that reduced the actual to 425 scan lines. A cell phone camera at 4MP has a resolution of 2688 x 1520 - the vertical resolution - 1520 - is over three times that of the tubes! The horizontal scan was a 4MHz signal (maximum - usually sets had lower bandpass and small, cheap sets could be half that - 2MHz).



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Offline DeadNutz

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Re: Old Video Camera Tubes
« Reply #1 on: May 19, 2021, 06:06:41 PM »
Thanks for posting that but it is mostly alien gobblygook to me. :a102:

Offline J.A.F.E.

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Re: Old Video Camera Tubes
« Reply #2 on: May 19, 2021, 06:25:12 PM »
I was hoping to avoid that. Sorry about that.
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Offline DeadNutz

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Re: Old Video Camera Tubes
« Reply #3 on: May 19, 2021, 06:55:08 PM »
If it was up to me to invent TV cameras you would only have the radio for entertainment.

Offline goodfellow

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Re: Old Video Camera Tubes
« Reply #4 on: May 19, 2021, 08:29:42 PM »
Fantastic Steve -- that artifact is a great piece of TV history.

Offline john k

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Re: Old Video Camera Tubes
« Reply #5 on: May 19, 2021, 09:39:53 PM »
Nice to see someone collect these artifacts, most of us have a few things folks would consider useless junk.   With the back story it sounds pretty fascinating.  Never seen tubes like these, but remember some hand blown tubes for early radio trannsmitters that were over 2 ft tall.

Offline J.A.F.E.

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Re: Old Video Camera Tubes
« Reply #6 on: May 19, 2021, 09:55:23 PM »
Les - I couldn't invent it either. I have worked on TV receivers although it's pretty much a dead skill anymore. But it is pretty cool and while TVs were still made from discreet components they were about the most complex item people owned.

GF - They are not common anymore but at one time every TV camera had one (or three for early color cameras).

john k - They are interesting and I do like them but I think it's time to get them into the hands of a real collector. Those huge tubes are still used. Broadcast transmitters usually still use tube outputs and I believe the shake tables use tubes as well.
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Offline skfarmer

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Re: Old Video Camera Tubes
« Reply #7 on: May 20, 2021, 06:54:25 AM »
Interesting. I really know very little about that old technology. I know Al little bit or at least enough to be dangerous about a lot of things. Electronics, even primitive stuff is not in my wheelhouse.
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Offline J.A.F.E.

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Re: Old Video Camera Tubes
« Reply #8 on: May 21, 2021, 11:29:47 AM »
It's pretty cool how things were done when they had to be done with individual components. Because in electronics you can't see moving parts like with gears and levers sometimes it is hard to see how it works but learning how those things work and how they work in different configurations can be really interesting.

Unfortunately it's all pretty much obsolete and mostly that knowledge will all get lost.
People who confuse etymology and entomology bug me in ways I can’t put into words.

Offline muddy

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Re: Old Video Camera Tubes
« Reply #9 on: May 24, 2021, 10:23:13 PM »
Neat stuff. Great write up. I read it...but only understood some. These are out of the camera that would be recording the actor or news, and not the tv correct?

Sent from the twisted mind of the mudman


Offline J.A.F.E.

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Re: Old Video Camera Tubes
« Reply #10 on: May 25, 2021, 09:02:08 AM »
Thank you.

Yes, these are camera tubes and what was behind the lens.

People who confuse etymology and entomology bug me in ways I can’t put into words.

Offline john k

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Re: Old Video Camera Tubes
« Reply #11 on: May 25, 2021, 01:58:37 PM »
Is it true that in the 40s, power generating plants had to adjust their output to 60 cycles,  or the picture would roll?  Took the networks pulling strings to make this happen.  Remember the pic rolling in tube sets a lot anyhow.

Offline J.A.F.E.

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Re: Old Video Camera Tubes
« Reply #12 on: May 25, 2021, 06:31:57 PM »
Is it true that in the 40s, power generating plants had to adjust their output to 60 cycles,  or the picture would roll?  Took the networks pulling strings to make this happen.  Remember the pic rolling in tube sets a lot anyhow.

Yes, the vertical scan uses the power line as a sync signal. The camera and the receiver have to be synchronized and the power line was the traditional signal.
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Offline goodfellow

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Re: Old Video Camera Tubes
« Reply #13 on: May 25, 2021, 08:29:20 PM »
Is it true that in the 40s, power generating plants had to adjust their output to 60 cycles,  or the picture would roll?  Took the networks pulling strings to make this happen.  Remember the pic rolling in tube sets a lot anyhow.

Interesting and fascinating history behind TV. I recall a History Channel series on the subject and it made mention that TV was demonstrated as a scientific technical marvel as early as the 1933-34 Chicago World's Fair and by the 1939-40 World's Fair in Flushing Meadows NY, RCA and others were already demonstrating affordable consumer TV sets to the public and high end transmission equipment to commercial broadcasters. That's and amazing development cycle for that technology. If it hadn't been for WWII, we would have had commercial TV much sooner.

Offline J.A.F.E.

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Re: Old Video Camera Tubes
« Reply #14 on: May 26, 2021, 01:19:39 AM »
I missed that program I'll see if it's on Utube. It's an interesting technology and it took as much development to make it commercially viable as it did to develop the technology. Sets had to be affordable (although they were very expensive and pretty much at the top end of affordable) and the signal had to work at all elevations, in all kinds of weather and most important it had to be affordable to build the broadcast equipment - TV had to be affordable for the advertisers.

Some really smart people worked on it and did some really clever engineering.
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Offline john k

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Re: Old Video Camera Tubes
« Reply #15 on: May 26, 2021, 02:16:45 PM »
Just read the story about the oldest Kennedy brother.  He was involved in a secret bombing program in WWII, where remote controlled B-17s were crashed into the target.   The Army Air Corps equipped them with tv cameras, the flying was done remotely by a mother ship a mile or more behind them, by someone watching a CRT.  All this in 1944!

Offline J.A.F.E.

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Re: Old Video Camera Tubes
« Reply #16 on: May 26, 2021, 03:33:49 PM »
That is most interesting. I did not know that but it's pretty cool.
People who confuse etymology and entomology bug me in ways I can’t put into words.

Offline goodfellow

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Re: Old Video Camera Tubes
« Reply #17 on: May 26, 2021, 04:17:33 PM »
Just read the story about the oldest Kennedy brother.  He was involved in a secret bombing program in WWII, where remote controlled B-17s were crashed into the target.   The Army Air Corps equipped them with tv cameras, the flying was done remotely by a mother ship a mile or more behind them, by someone watching a CRT.  All this in 1944!

Joe Jr. was the real deal. Pretty amazing guy, and had he lived he would have definitely been a political star.




Offline john k

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Re: Old Video Camera Tubes
« Reply #18 on: May 26, 2021, 04:24:21 PM »
The volunteer pilots would take off in these planes literally stuffed with high explosves, then bail out before reaching the English channel.   Joe Kennedys plane malfunctioned,  fireball.

Offline DeadNutz

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Re: Old Video Camera Tubes
« Reply #19 on: May 26, 2021, 06:15:30 PM »
The volunteer pilots would take off in these planes literally stuffed with high explosves, then bail out before reaching the English channel.   Joe Kennedys plane malfunctioned,  fireball.


Yes, his B-24 exploded before he could bail out.