The problem with the web is that sometimes you hit a website that drags you off into a direction completely unrelated to anything you've really considered before.
This happened to me most recently when I encountered a site which described
the work of John Logie Baird, a Scottish engineer who designed a television system that transmitted 30 line images and was used in the first public broadcasts by the BBC. Some of these early transmissions have been restored and documented in a rather interesting looking book entitled Restoring Baird's Image by Don McLean.
Curiously enough, there are still amateurs who are devoted in building replicas of these early mechanical televisions. Some links: