1930s Video Disc

Posted on Thursday 2 December 2004 to unknown

Ten Cents an Dance

Ten cents a dance,
that's what they pay me
Gosh, how they weigh me down
Ten cents a dance,
pansies and rough guys
Tough guys who tear my gown

Seven to midnight I hear drums
Loudly the saxophone blows
Trumpets are tearing my eardrums
Customers crush my toes

Sometimes I think I've found my hero
But it's a queer romance
All that you need is a ticket
Come on, big boy, ten cents a dance!


Those are very likely not the words that Betty Bolton is singing in this particular clip but this song was her best known hit. Unfortunately the clip is silent so we don't get to hear her famous contralto singing voice but what you can see is pretty damned remarkable in itself. It's a fragment of a very early television broadcast from the early 1930s which had been recorded off the air waves by amateur enthusiast using a home gramophone recording system (you can watch the rest of the sequence here as a RealMedia clip).

This is a video disc made decades ahead of its time and one which offers us a glimpse - however imperfect - into the long vanished world of mechanical televison.

Between 1932 and 1935, the BBC broadcast over fifteen hundred programmes as part of an evaluation of John Logie Baird's mechanical television system. The basic principle behind this system, which was first proposed by Paul Nipkow in 1884 but only made practical in 1926 by Baird himself, was to send a screen's worth of information down a wire by scanning it with a disk that contained a series of holes arranged as a spiral. As the disk turned one of the holes would allow a focused beam of intense light to pass through and reflect off the subject's face eventually registering as an intensity level on a photo detector.

The signal from the photocell could then be transmitted and received at the opposite end by a complementary set of hardware, another disk and a flickering neon lamp. As this disk turned the lamp would switch on an off presenting light and dark patches at different locations on a tiny screen only a few inches wide.


The original television system was designed to be transmitted with narrow bandwidth requirements over a medium wave radio signal (the AM radio band). This meant that the definition of the image needed to be low, the horizontal resolution was only 30 pixels. This however had the advantage than the Baird television signal, in addition to being able to be transmitted over the wireless, could also be sent down a telephone line and even, as we have seen, be recorded on a gramophone record.

We are very lucky to be able to see this image at all, the disk had languished unseen for more than sixty years before being rediscovered and restored in 1998 by signal engineer Don McClean. It's also important to realise that the quality of the image in the recording is considerably poorer than what it would have looked like when it was originally broadcast because of speed variations and signal distortion in the gramophone recording system itself. Here is a modern reconstruction of mechanical system based on Baird's 30-line format. The light is being produced with a LED instead of a neon light.


Even at the time when the Betty Bolton performance was being transmitted the writing was on the wall for mechanical television with all-electronic systems being developed by rivals EMI-Marconi in Britain and RCA in the United States. On the 11th of September, 1935, the BBC closed down its 30-line service and overnight orphaned several thousand Baird television receivers.

A year later the Beeb began trialling a "high definition" system which based on the cathode ray tube.

You can see a number of other restored recordings on Don McClean's website as well as other interesting tidbits about the dawn of television. Finally, here are some tips on what to do when your mechanical television image goes blooey.