Vintage electronics month: video killed the radio star

By Mike on 3:29 pm

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Radio was the first major electronic device to win the hearts of consumers. But like every other gadget, people weren't satisfied. Sure, you could listen to a concert at Carnegie Hall. That was revolutionary. Still, you couldn't watch the performance as if you were actually there. What if you could?

Developing a system that could transmit both sound and pictures was the holy grail for radio engineers, even before radio was invented.

The roots of such a system can be traced back to 1840, to the 1840s when Scottish inventor Alexander Bain proved it was possible to send images electrically. His complex device used a clockwork system to scan a message and transfer it to a series of electrical pins on a drum. The electrical signals sent by the machine could be reproduced on the other end. In 1861, Italian physicist Giovanni Caselli made a practical version of this device. We know it today as the fax machine.

The next evolution came in 1873, from an English inventor named Willoughby Smith. He was trying to develop a system to test underwater cables as they were being laid. Smith tried using selenium electrodes. Quite by accident, he found the electrical conductivity of the selenium rods dropped when exposed to a bright light. This property of selenium could be used to turn light into electrical signals. The discovery would eventually give birth to electrical cameras.

In 1883, German technician Paul Gottlieb Nipkow developed a perforated disk after reportedly being inspired from beams of light coming from a lamp. The holes were positioned in a spiral pattern and could, in theory, reproduce an image via mosaic of points and lines.

The basis for reproducing images had been laid by the early 1900s. Georges Rignoux and A. Fournier had managed to reproduce images using selenium cells in Paris in 1909. In 1911, Russian scientist Boris Rosing and his student Vladimir Zworykin invented a system to display crude images over wires using a cathode ray tube.

It wasn't until 1925 when the first practical device for showing video first appeared. Scottish engineer John Logie Baird took a Nipkow's disk and worked it into a mechanical device for showing moving pictures. A modulated light source was used in conjunction with the perforated aluminum disc, which was spun with a motor. As each hole passed by, it created a single line in the image. It used AM radio waves to receive the image transmitted from a similar device that acted as the camera. He called his invention the Televisor. The first image it received was "Stooky Bill", a ventriloquist dummy. The Televisor could reproduce images in 30 vertical lines, at five frames per second. The picture was extremely small by today's standards. Maybe about an inch across.

Baird's Televisor. Early Television Museum

The Televisor revolutionized radio. However, it came about at the worst possible time. When the Great depression hit In 1929, people weren't concerned about moving pictures in the home. Baird only began regular broadcasts through the BBC in that year. The technology was also rapidly improving. By the time the Televisor was being mass marketed, it was already obsolete.

The Televisor produced crude yet recognizable images

In 1927, American inventor Philo Farnsworth demonstrated the first all-electronic television. The 21-year-old's device used a cathode ray tube instead of a Nipkow disk. It has no moving parts, had a larger screen, and produced better quality pictures.

German electronic television

By the 1930s, the us Federal Communications Commission settled on the Farnsworth design as the future of television. By 1941, the familiar 525 line NTSC format was adopted in the US. The format is still widely used 70 years later. After the end of WWII, televisions became a staple of North American households. It hailed the end of radio's golden era as programming moved to TV.

Images courtesy of Wikipedia & The Early Television Museum

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