A century ago, the inventor Edwin H. Armstrong enabled a vacuum tube to amplify an electronic signal through a positive feedback loop. In other words, he developed the regenerative circuit that provided reception to most radios of the 1920s and ’30s before more advanced methods took its place. Still, that hasn’t stopped IEEE Member Ron Kay from spending the last 15 years building old-time regenerative radios from scratch.
Kay’s projects are vacuum tube-driven radios that pick up international shortwave reception in the 5- to 10-megahertz range.
BUILDING REGENERATIVE RADIOS
“The trick to making them work is to carefully adjust the amount of positive feedback to the point just prior to oscillation,” says Kay, a research engineer who works with lasers at the University of New Mexico’s Center for High Technology, in Albuquerque. “If the gain gets too high, you get that squealing sound. It’s like tuning a musical instrument.”
He has built five regenerative radios so far, all battery-powered with two or three vacuum tubes each. The radios vary in size, although typically they are 19 centimeters long, 8 cm wide, and about 19 cm high. Kay leaves his sets uncovered. “Partly it’s because I like to see the individual components,” he says. “I see the radios more as sculptural objects. But there are practical reasons, as well. By not having a top, the coil can easily be changed out for a different one, which can tune a different range of frequencies. A top would just get in the way.”
Vacuum tubes are readily available if you know where to look. Russia and China still make tubes; the United States stopped making them around 1980. The total cost of new parts could run to US $100, but scouring antique radio swap meets, “hamfests” (ham operator gatherings), garage sales, and eBay sometimes yields used capacitors, inductors, resistors, and tubes for about a quarter the price. “Building a radio to look like a radio of its time period with new parts and a fine wood finish could run many hundreds of dollars” because of the woodworking costs, Kay adds.
Kay got hooked on radios when he was 9 years old, in 1961. He was transfixed by a crystal radio, which runs on power from radio waves picked up by a long antenna. He was especially interested in how a wire-wrapped galena crystal—a form of lead—could receive radio waves. Such radios were made with just a few parts: an antenna (to receive and convert radio waves into electric signals), the crystal detector (to demodulate the signals), a wire coil inductor with a capacitor across it for tuning, and a headset to convert the signals into sound.
As a teen, Kay taught himself to build radio circuits from books. “There is a skill associated not only with building, but also using, these radios,” he says. “Anyone can log on to Radio Netherlands from a computer in Albuquerque, for example. But receiving an actual transmission with one of these radios is not so easy. Tuning alone will not get the signal to come in. You must adjust both tuning and regeneration—the amount of positive feedback—interactively to receive a clear signal. It takes some practice.
“It’s amazing how well these radios work with such a simple and primitive circuit,” he continues. “There are a number of ways to configure the circuit, with either bipolar or field-effect transistors, and I’m looking forward to experimenting with these in the future.”
Engineering requires creativity and problem-solving skills, but IEEE Graduate Student Member Ayodeji Omole also likes to channel his more existential side through his essay writing and poetry about the human condition.
WRITING ESSAYS AND POETRY
GRADUATE ENGINEERING STUDENT
“I have a profound urge to help people see how they can become better versions of themselves, and I do this by writing inspiring articles,” says Omole, a graduate student originally from Ilesa, Nigeria, who is studying electrical power engineering at Newcastle University, in Newcastle upon Tyne, England. “I also write poems, because I see poetry as a beautiful way of expressing myself and relating to my environment.”
Omole spends at least five hours a week writing creative works. He tries to craft at least two articles and one poem every two weeks, then posts them on his blog, Inspirations Within as well as on social media websites and Poetry.com. Omole is compiling many of his writings into a book, You Are Born a Genius, which he hopes to submit to publishers by early next year.
He began writing in high school in Nigeria, honing his skills by submitting his work to national essay contests. He never won, but his writing improved. In 2009, during his second year at Ladoke Akintola University of Technology in Ogbomosho, Nigeria, he began writing articles for the student-run engineering magazine, Electroscope. Poetry soon followed.
“I expressed my thoughts in short verses that I know now could pass as free-verse poems. Because they didn’t rhyme or follow a certain pattern, I never thought of them as poetry,” he says. “I was inspired to write my first poem, ‘For a Greater Good,’ when I lost a close family friend in 2010. I’ve since written more than 20 poems.”
Omole’s writings bridge his engineering and esoteric sides, offering logical approaches to ethereal meditations on such topics as destiny, humility, life fulfillment, and making assumptions about people. Some pieces involve lessons he’s learned from his experiences, such as the required year of community service in Nigeria’s National Youth Service Corps; others tie in spirituality and observations about human behavior.
Omole writes in English, occasionally incorporating Nigerian Pidgin, an English-based pidgin and creole lingua franca (which refers to languages that were developed over time to facilitate communication among those who do not share a native tongue).
“Although most of my pieces do not focus on engineering, being an engineer has shaped my writing,” he says. “I am able to present my thoughts in more logical ways, which in turn helps me produce better technical reports in engineering.
“Writing also aids critical thinking, which has helped me a lot in my engineering studies,” Omole says.
Photos, top: Ron Kay; bottom: Stephen Udochukwu Eze