Radio's as a whole aren't an old technology, and yet we still seem to consiter them just a relic of the past. There is still alot you can learn from the technology of the past, but we're catching the last of a generation for whom radios were a much bigger part of life. It won't be long before we will read about them as just another period in history, and not our neighbors down the street.
I've noticed that there is nearly nothing about old radio on instructables, but I'm sure if you get started you'll find it to be fascinating, and applicable to all modern technology. You will learn from the most basic circuts and theory to complicated modern uses. So let's see what we can discover :)
Step 1: The Search
Radio's aren't easy to jump into by yourself, most often you'll want to find it's easiest to obtain the help of someone who already knows it all to explain the more complicated topics. Finding someone today may be just as hard as finding the right references, but that's what I'm here for :) to share what I've done on my own. A great place to start will be in reading the most basic electrical engineering text book you can find, the best are the old ones, the basic ideas haven't changed. I've had great luck at http:// http://www.tubebooks.org/technical_books_online.htm
Step 2: Good Luck
Good luck with your reading, and as I learn more I hope to work my way up to some building projects. If you have any suggestions or would like to help don't hesitate I am just trying to fill a void in information, and share my interest. I would love some help, or to see others start posting what they know.