Larry Kilham Blog
Larry Kilham Blog
For me, it all started with a deep dive into the magic world of electronics.
When I was twelve or so I became interested in electronics by making “crystal radios.” Using a coil wound on a toilet paper tube for tuning to a station, a safety pin called the cat whisker, a chunk of galena crystal ordered through the mail, a capacitor, headphones, and a very long antenna, you could listen to the local radio station. The cat whisker touching the galena crystal served as a rudimentary semiconductor diode. The diode would “rectify” or convert the radio frequency signal from the radio station. The result would be a faint audio signal which you could hear on headphones but not a speaker.
My curiosity pushed me further. I found that a Gillette razor blade worked just as well as the purchased galena. The blade had to be slightly rusted giving an oxide layer, and only certain sites on the blade could be found that worked.
Then I started to think, “If I connected a battery to the razor blade with a second cat whisker, couldn’t I amplify the faint signal?” Night after night I tried moving the cat whiskers around on the blade but I only got the original faint signal and lots of static. Then, suddenly, there it was! The voice of WARA announced the evening music. I could hear it from the headphones held at arm's length! This only lasted for maybe a minute, then I lost the amplified signal and could never regain it.
My discovery was of course serendipitous and I didn’t understand the theory of the circuit’s operation, but this adventure in curiosity started my interesting and remunerative career.
I had discovered that with a second cat whisker and a battery you could amplify the radio signal. I was too young and naïve to understand that I may have discovered the transistor before I was aware of this major invention. This was in 1953. The transistor was invented in 1947 by American physicists Walter Shockley, John Bardeen and Walter Brattain at Bell Laboratories, but the first practical transistor radio was not put on sale until 1954. Their first attempts at a working transistor were similar to mine where they kept moving two closely adjacent gold cat whiskers around on a germanium semiconductor and, like me, not being able to keep the signal once they found it. This configuration is called a point-contact transistor. Eventually of course, they developed much more sophisticated techniques and materials, unavailable to me. They received a Nobel Prize for their efforts.
Most transistors today are minuscule and have no cat whiskers. Over eight billion are packed into the few circuit chips of a cell phone. They are called MOSFETs for metal oxide semiconductor field effect transistors.
This experimentation led me to an interest in “ham radio” where with receivers, transmitters and an official license you could telegraph by Morse code or even talk by microphone all over the world. Eye-popping stuff for a country boy. I eventually designed my own circuits drawing upon intuitive modifications of circuits found in ham radio magazines. Years later, I would learn how to design circuits using electrical engineering theory, but that was never as satisfying. However, it did lead to the basis for several instrumentation companies I started and sold.
Electronics became an obsession for me. I had entered a world of magic. I built small radios from mail-order kits and learned basic electronics on my own through trial and error. I began to build my radio equipment from scratch. I connected to ham radio operators in the United States and many exotic places around the world. As the years passed, I accumulated a collection of strange-looking radio antennas, connected from tree to tree, pole to building, and even as tall towers. When the ionospheric conditions were right, I could talk all day to other ham radio operators all over the world.
After digging deeper into the mysteries of electronics, I decided to study electrical engineering. Among many university projects that absorbed my time and energy, I rebuilt a radar set. I worked with an ultrasensitive radio receiver that listened to stars light-years away and I programmed computers. I researched electronics that might at some point assume human intelligence. I managed to cover most of my college costs by writing software for my professors, and I felt confident that my future was bright.
Curiosity became my mental engine. It propelled me forward when I needed to find and develop a body of knowledge I could call my own. It is never too early or too late to define your curiosity.