Ain't Technology Wonderful - 1930s Version

[Gord_in_Toronto]

1930s How Photographs Were Transmitted by Wire



Quite an involved process compared with today.

Nice explanation however.

 

[Skeptic Ginger]

Loved it but I did have to skip past a fair bit in the middle explaining the details.

 

[Jack by the hedge]

An episode of "The Secret Life of Machines" explaining fax machines includes a part of that film. Then they bodged together their own fax machines using their (nearly) synchronised lathes to send a picture between Tim and Rex's workshops.

https://www.youtube.com/watch?v=IaCfs5Xb-EI

film clip about 9:20 and "fax" about 12:30

 

[rjh01]

The problem with this method is that if the drums are not rotating at exactly the same speed the photo will come out distorted.

 

[Gord_in_Toronto]

The problem with this method is that if the drums are not rotating at exactly the same speed the photo will come out distorted.

Are you old enough to remember the horizontal and vertical hold knobs on TVs? You had to adjust the synchronization by hand.

 

[Jack by the hedge]

The lathe example shows how much trouble Rex had getting the "horizontal hold" of his lathe just right.

Thankfully with old TVs the horizontal and vertical hold did adjust itself automatically, otherwise the picture would always be very slowly rolling or sliding, but you sometimes needed to adjust the settings to get them close enough to a position where the circuit could detect the synch signals it needed in order to lock on.

 

[Beerina]

The problem with this method is that if the drums are not rotating at exactly the same speed the photo will come out distorted.

I suspect the string example at the beginning was having an additive misalignment, not because the cylinders were different, but because the string stretches slightly, and doesn't wind onto the bottom cylinder with the same tightness as the top, and hence they had to fix it by hand so it looked nice. It was suspicious they went from almost nothing and then jumped to half car done.