405 line Mechanical Television

[peter scott]

Now here's a challenge!

This article was published December 1938 Television & Short Wave World.

   

[ppppenguin]

It's hard to tell what they were really doing. It's not quite a description of the Scophony receiver. A fully mechanical 405 set would have been a very difficult thing to make. 240 lines was hard enough.

It may well have been a dubious/fantasy claim.

[Murphyv310]

Hi.
From what I read in the article they used a bulb for the light source over run and modulated by a fancy oscillator. No filament bulb would ever on Gods earth respond fast enough to that kind of modulation. My feeling is the write up is a figment of someone's imagination.

[peter scott]

It did imply that it was for receiving current signals from AP so definitely 405 line interlaced.

They do suggest that suitable scanners and motors were available from H.E. Sanders & Co. so perhaps they were just going to offer instructions on how to construct the light valve.

Peter

[Murphyv310]

Its possibly feasible today, with high precision facilities to make discs, fast Luxeon LED's etc. Two discs would be needed if I'm right but the speed of the discs surely would need to them to run in a vacuum.
Even Baird acknowledged that the receiver needed a CRT not a mechanical device, it would have been big and expensive.

[peter scott]

No large discs. No vacuum needed. 30,375 rpm from a combination synchronous and induction motor.
See page 593.
https://www.americanradiohistory.com/Arc...-10-UK.pdf



Peter

[peter scott]

It looks as if the high speed scanner can be much smaller than the one in my previous post.
I'm sure Mr Dyson could come up with a nice "digital" design.

Peter

   

[peter scott]

http://www.tvhistory.tv/1938-Scophony-UK.htm

http://www.earlytelevision.org/scophony.html

[ppppenguin]

That motor is one of the very few Scophony bits to have survived. It belongs to the Science Museum. I saw it when John Trenouth brought it to a meeting at Blythe House years ago. There are no complete or even partial sets.

[Murphyv310]

I'll have a read later Peter. You took the words right out of my mouth re Mr Dyson. I believe the motor on our V6 runs up to 30, 000 odd rpm so an ideal candidate.
When are you building yours then?