Ohio

115

Early Television Museum, Hillard, OH

40° 2′ 3.67″ N, 83° 9′ 41.17″ W

What’s In, Not On, the Box

There are many museums of television around the world, but the Early Television Museum is the most fun for the scientific traveler: it’s dedicated to the mechanics and electronics of television, as opposed to the stars who appear on the small screen. And the museum is hands-on, with a demonstration of 1930s television technology.

The museum’s collection begins with the mechanical television sets of the 1920s and 1930s, which had between 30 and 60 lines (compared with 480 visible lines on a conventional NTSC TV set). The museum’s collection includes a working 1930 Baird Televisor (which originally came as a kit; see Figure 115-1), and a Davin Tri Standard built from articles that appeared in Popular Mechanics at the end of 1928. Many other TVs from this era are on display and in working order.

Figure 115-1. 1930 Baird televisor; courtesy of the Early Television Museum

The museum’s collection continues with black-and-white electronic televisions starting in 1936. There’s a large collection of U.S. televisions as well as a collection of British, European, and South American sets. Many of these are also in working order, as the Early Television Foundation (which runs the museum) works to keep history alive by restoring or repairing its exhibits.

The first color television sets on display date to the early 1950s and include an operational RCA CT-100 and a Westinghouse H840CK15: the first two color televisions made available to the public in 1954.

The transmitting side of TV is not overlooked, either. There’s a collection of cameras, monitors, and test equipment, and another of TV tubes, antennas, and accessories. There’s even a mobile TV transmission van dating from 1948.

And no visitor should miss the chance to appear on 1930s television. The museum has restored an RCA flying spot camera, which traces a spot of light over the visitor’s face to build up an image. Stand in front of this camera, and your face will appear on a working 60-line 1930 RCA television set.

Practical Information

The museum is free, but donations are always encouraged. Information about visiting can be found at http://www.earlytelevision.org/. Each May, the Early Television Foundation (which runs the museum) organizes an Early Television Convention, with presentations covering television technology and an auction of TV parts.

John Logie Baird’s Invention

In 1926, Scottish inventor John Logie Baird demonstrated a working television that he called the Televisor. The apparatus was crude, but it worked. The camera consisted of a rotating disc with a spiral of holes in it; light passed through the disc and onto a photocell. The resistance of the photocell changed with the amount of light falling on it, and the rotating spiral essentially scanned the image vertically, line by line. The varying current through the photocell could then be transmitted by phone or radio.

The television receiver had a similar rotating disc with a light behind it. The intensity of the light varied with the incoming television signal, so that its intensity matched the intensity of the light falling on the camera’s photocell. By synchronizing the rotation of the two discs so that the same point was being scanned and projected at the same time, an image appeared on the television receiver’s tiny screen.

Baird’s first demonstration involved transmitting a picture of a ventriloquist’s doll’s head into the next room. The camera scanned 12.5 images per second with just 16 lines, and the image was faint and blurry—but for the first time, a moving image could be transmitted live.

John Logie Baird is widely credited as having been the first to demonstrate a practical television system, and he was intimately involved with the BBC’s early television transmissions. But mechanical television was not a great success because the image quality was poor, and it was gradually replaced by electronic television systems invented by Kálmán Tihanyi, Vladimir Zworykin, and Philo Farnsworth.

Nevertheless, the fundamental idea of scanning an image line by line and reproducing it line by line remains intact to this day.