[HN Gopher] In 1926, TV Was Mechanical
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In 1926, TV Was Mechanical
Author : jnord
Score : 85 points
Date : 2024-09-17 07:28 UTC (15 hours ago)
(HTM) web link (spectrum.ieee.org)
(TXT) w3m dump (spectrum.ieee.org)
| Animats wrote:
| There's a long history there. See the Early Television Museum.[1]
|
| It's sad that no Scophony set survives. High resolution and 24
| inch screens in 1938.
|
| [1] http://earlytelevision.org/mechanical.html
| xattt wrote:
| > 2 mHz
|
| TV broadcasts sure were frequency efficient.
| avhon1 wrote:
| With pictures "made up of only 30 to 60 lines", they were
| transmitting _much_ less data!
| mrguyorama wrote:
| Full blown color NTSC managed with 6mhz channels! Digital
| broadcasts have a terrible user experience: Instead of
| providing the same channel they always did, but to vastly
| more receivers in much more marginal conditions using
| advances in digital signal processing and encoding power
| and methodology, broadcasters were allowed to cut up their
| frequency into 6 "subchannels", so they crunch the streams
| to the shittiest quality they can (as low as 3mb/s, DVD is
| 10!) legally get away with, provide almost zero redundancy
| in the broadcast, so now TVs that were well in the
| broadcast area of analog signals are straining to get every
| last bit out of the digital stream so it can hope to
| recover a picture.
|
| They did this because 6 channels that most people cannot
| actually receive over the air gives them more advertisement
| slots than the 1 previous channel. Good old
| enshittification.
| JadeNB wrote:
| > Full blown color NTSC managed with 6mhz channels!
|
| I think that the point was that 2 (or 6) mHz is a much
| lower frequency than 2 (or 6) MHz, and the latter is
| almost surely what was meant.
| xattt wrote:
| Yes, the comment was tongue-in-cheek regarding the units
| ;)
| kragen wrote:
| at two millihertz of bandwidth, you could transmit a
| 30-pixel line in only 7500 seconds, so you could transmit
| an entire 30x30 frame in 225 000 seconds, less than three
| days
|
| but plausibly the millihertz notation was an error and
| megahertz was meant
| alenrozac wrote:
| interestingly close publish date to Asianometry's video on Sony's
| Breakthrough Color TV:
| https://www.youtube.com/watch?v=TOh3jEJGynA
| elpocko wrote:
| Not so interesting. In the video description and in the video
| itself it's pointed out that it's done in a collaboration with
| IEEE Spectrum.
| burkaman wrote:
| Reminds me of this fully mechanical ancient Greek movie from
| 2000+ years ago: https://www.youtube.com/watch?v=IW3uaJimMlI
| taeric wrote:
| This reminds me of the equally interesting framing of modern
| computer failure rates in similar terms to mechanical parts.
|
| This is also a very fun exploration of how many things start
| mechanical and move to more solid state as they age. I'm curious
| what major mechanical items are left to move over to solid state?
| My guess is most things that have changed were instruments in
| larger things. Gyroscope devices are a fun example.
| aftbit wrote:
| So much was done with mechanical systems back in the day, because
| they were better understood and comparatively cheaper than
| corresponding electrics. I wonder if the engineers who designed
| teletypes or artillery range computers could learn to program,
| and if they did, would they have any unique insights?
| bee_rider wrote:
| Krylov (the guy the subspaces are named after) was a naval
| engineer. Cholesky was an artillery officer.
| tway_GdBRwW wrote:
| I love this unique insight:
|
| "Fire control computers ... solve ... fire control problems."
|
| https://www.youtube.com/watch?v=gwf5mAlI7Ug
|
| U.S. NAVY BASIC MECHANISMS OF FIRE CONTROL COMPUTERS
| MECHANICAL COMPUTER INSTRUCTIONAL FILM 27794
| bee_rider wrote:
| Those old educational videos are a lesson in how to give
| presentations I think. There's an art to the way they build
| up a fairly complicated concept step by step. The viewers
| are starting from zero after all.
|
| The starting step is one that is impossible to
| misunderstand. From there, go one concrete step to another.
| Animats wrote:
| Feynman did some mechanical artillery range computer design.
| Read "Surely you're joking, Mr. Feynman". He has a few things
| to say about it.
| 082349872349872 wrote:
| They'd probably take a dependency, slice out the quarter they
| actually use, and somehow turn it into a cleverly-encoded
| lookup table or two?
| andrehacker wrote:
| There is a great model kit made in England for the "Televisor".
| Got it years ago and it was minutes of fun. Apparently still for
| sale. The input is audio, got it to run from my iphone at the
| time (as opposed to using the supplied CD which in itself is
| Retro technology). I had some plans to build code a video-to-
| audio converter to run this (or screengrab to audio for that
| matter).
|
| https://www.youtube.com/watch?v=fTSeUjvScUA
| mrandish wrote:
| Several years ago I came across the first issue of "Television"
| magazine from 1928 and reading it blew my mind in a couple ways.
| First, the overall tone is remarkably similar to a 1970s homebrew
| computer club newsletter, including defining what "television"
| even is (and isn't). For example, We learn on page 10 that
| "television is _not_ tele-photography. "
|
| It's clear from this magazine that early television was the
| domain of home tinkerers and hackers. On page 26 is a detailed
| tutorial on how to construct your own selenium condenser cell
| from scratch, including which London chemist had appropriately
| high-quality selenium, where to buy copper sheets, mica insulator
| (.008 thick) and brass bars. Well worth a read:
| https://comicbookplus.com/?dlid=37097
|
| That analog television not only was prototyped nearly a hundred
| years ago but then began being deployed at vast consumer scale
| ~75 years ago is still just so amazing. It's worth understanding
| a bit about how it works just to appreciate what a wildly
| ambitious hack it was. From real-time image acquisition to
| transmission to display, many of the fundamental technologies
| didn't even exist and had to be invented then perfected for it to
| work.
| dTal wrote:
| Although it's about wire transmission of photography - which,
| as pointed out, television is _not_ - it 's still well worth
| watching this 1937 newsreel explaining how it works, mostly
| because 1) they devote a LOT of time towards explaining the
| concept of scanning/rastering, which was clearly not widely
| intuited at the time, and 2) they do it with a _brilliant_
| physical analogy, with the incredible pedagogical clarity
| typical of such 1930s educational videos.
|
| https://youtu.be/cLUD_NGE370?
| IIAOPSW wrote:
| First time I watched that I forgot I had the speed set to 1.5
| or something so the already fast-talking 1930s mid-atlantic
| radio announcer voice got exaggerated to a hilarious degree.
| Especially funny as the first few lines were about the
| importance of speed!
| UncleSlacky wrote:
| There were even recordings of it, though they couldn't be played
| back at the time:
|
| http://www.tvdawn.com/
| phkahler wrote:
| Also interesting is the electromechanical "tone wheel generator"
| used in the Hammond Organs:
|
| https://forums.musicplayer.com/topic/155607-a-look-inside-a-...
|
| 91 metal wheels with lobes spinning past something like electric
| guitar pickups to produce sine waves. Their goal was to produce
| pure sine waves and then combine them via "drawbars" to produce
| an adjustable sound. 12 different gear ratios and different
| number of lobes (powers of two) to produce all the frequencies.
|
| The rotating "Leslie" speaker was also cool, as is the
| electromechanical "vibrato scanner" on later models.
| bryanmgreen wrote:
| Very cool. Makes me think of this wonderful scene from Sports
| Night where William Macy talks about Philo Farnsworth and Cliff
| Gardner inventing TV.
|
| https://www.youtube.com/watch?v=H-va0tWJLTc
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