It can often be quite interesting to look back at radio technology, and see where we came from. I am not merely talking about vacuum tubes, which were formerly called “valves”. No, I am looking at something slightly older. Specifically, I am talking about Crystal Radio.
Huh? Crystal Radio? What is that?
Good question. At its absolute simplest, a crystal radio is a receiver with no actual power supply. Rather, it is the received signal that powers the high impedance ear bug, through which you can hear the incoming audio.
What? No power supply? As in no batteries? Absolutely. Not only that, but this is how many amateur radio operators and electronics technicians got started.
Over the course of the next few months, it is my intent to fully delve into this topic. This post is merely an icebreaker, a teaser if you will. In Part 2, we will go more in depth, discussing materials used, and how it works. In Part 3, we will begin the process of building two radically different radios based upon the same schematic diagram, starting with the coil and antenna. In Part 4, we will continue the build, with one radio having a germanium diode, and the other using an iron pryrite crystal with a “cat-whisker” detector. Part 5 is where we will compare the two radios, and discuss practical applications.
This is going to get interesting. Please don’t let yourself miss out.