brainwagon

Comment from James T. Hawes
Time 11/25/2007 at 2:33 pm

Thanks for posting links to these mechanical television classics. The originals are becoming rare and very expensive. This fact especially applies to the Grisewood text. I suppose that’s true because the slip cover brags that this is the first US-published TV book. I doubt the truth of that statement, but Grisewood is certainly one of the first. One problem with that claim is that television actually predates the 20th century.

Fortunately Lindsay Publications reprinted the book Experimental Television. Among other things, this book documents the unique “revolving belt” receivers of Boston’s Hollis Baird. The homemade TV section is superb, and includes circuits. The camera circuits are extremely rare. I’ve spent hours of fun in adapting such vacuum tube circuits to semiconductors.

At one time, JWF Puett (Puett Electronics) demand-printed the ABC of Television. You could order the book from Puett’s small business in Texas. This book details mechanical television mechanics, circuits and theory. But the book goes further. It even relates the romance of receiving early telecasts on homemade equipment.

I enjoyed your enigma pages, too. I’m also a fan of the enigma, and am quite fascinated with stories of Bletchley Park. The renowned Alan Turing was one of the geniuses behind the efforts at Bletchley. He was one of the designers of the Bombe deciphering machine.

By the way: Have you read about the Colossus deciphering machine? It conquered the German Lorenz ciphers, which were even more complex than what the enigma could produce. See… http://www.bletchleypark.org.uk/content/machines.rhtm

Brilliant engineer Tommy Flowers designed Colossus. In his eighties, he oversaw its reconstruction from scratch. The British government had classified or destroyed the original drawings. No problem. Flowers managed to recall the entire design in detail! Unfortunately, he died just before or just after the machine became active.

I’ve shown the PBS enigma show to local ham groups a few times. At one meeting, a friend gave me photos of an enigma that showed up at the Dayton Hamvention! PBS might still have its enigma site up on the Web. On the show, several of the original Bletchley staff provide live interviews. The site also has do-it-yourself decrypting exercises. I’m sure that these would be far too elementary for you.

Here’s another page that might interest you, too…
http://www.skywaves.ar88.net/SPY/spy.htm

This page is about a POW radio that captured soldiers secretly built with scavenged parts. The soldering iron was a cauterizing tool. I love these homemade projects. They prove that necessity is still mother of invention. Also, that many times, a barebones contraption will do the job.

Another lesson is that one man can conceive of a prototype. Perfecting the invention takes the work of many men. Afterward, few understand the technology, and most have forgotten the prototype. Yet the prototype is key, and often it works well enough. For example: The POW radio, as an example of essential radio technology, is a working prototype. A simple mechanical TV set is another such prototype. Here is both a concrete example of the entire technology, plus the concept. You get both, in one item!