Chances are you have at least one radio that can receive FM stations. Even though FM is becoming less used now with Internet and satellite options, it still is more popular than the older AM radio bands. FM was the brainchild of an inventor you may have heard of — Edwin Armstrong — but you probably don’t know the whole story. It could make a sort of radio-themed soap opera. It is a story of innovation, but also a story of personal vanity, corporate greed, stubbornness, marital problems, and even suicide. The only thing missing is a long-lost identical twin sibling to turn it into a full telenovela.
Armstrong grew up in New York and because of an illness that gave him a tic and caused him to be homeschooled, he was somewhat of a loner. He threw himself into his interest in electric and mechanical devices. By 1909 he was enrolled in Columbia University where professors noted he was very focused on what interested him but indifferent to other studies. He was also known as someone more interested in practical results than theory. He received an electrical engineering degree in 1913.
Unlike a lot of college graduates, Armstrong didn’t go work for a big firm. Instead, he set up a self-financed independent lab at Columbia. This sounded good because it meant that he would own the patents on anything invented there. But it would turn out to be a two-edged sword.
Continue reading “Edwin Armstrong’s Battle for FM Radio”
July 20th, 1969 was the day that people from Earth set foot on different soil for the first time. Here we are 48 years later, and the world’s space programs are — well — not very close to returning to the moon. If you aren’t old enough to remember, it was really amazing. The world was in a lot of turmoil in the 1960s (and still is, of course) but everyone stopped to look at the sky and listen to the sound of [Neil Armstrong] taking that first step. It was shocking in a good way and almost universally observed. Practically everyone in the world was focused on that one event. You can see some of that in the NASA video, below.
Space flight was an incredible accomplishment, but it paled in comparison with the push to actually landing a person on the moon and bringing them home safely. The effort is a credit to the ability of people to work together (on the order of thousands of minds) to overcome a difficult challenge. We can learn a lot from that alone, and it makes a compelling argument to continue taking on tough problems. Today, as we remember the Apollo landings, let’s take a moment to recognize what came of it beyond an iconic boot-print in the floury lunar soil.
Continue reading “Beyond a Boot Print: The Lasting Effect of Apollo on Humanity”
Crystal radios used to be the “gateway drug” into hobby electronics. Trouble was, there’s only so much one can hope to accomplish with a wire-wrapped oatmeal carton, a safety-pin, and a razor blade. Adding a few components and exploring the regenerative circuit can prove to be a little more engaging, and that’s where this simple breadboard regen radio comes in.
Sometimes it’s the simple concepts that can capture the imagination, and revisiting the classics is a great way to do it. Basically a reiteration of [Armstrong]’s original 1912 regenerative design, [VonAcht] uses silicon where glass was used, but the principle is the same. A little of the amplified RF signal is fed back into the tuned circuit through an additional coil on the ferrite rod that acts as the receiver’s antenna. Positive feedback amplifies the RF even more, a germanium diode envelope detector demodulates the signal, and the audio is passed to a simple op amp stage for driving a headphone.
Amenable to solderless breadboarding, or even literal breadboard construction using dead bug or Manhattan wiring, the circuit invites experimentation and looks like fun to fiddle with. And getting a handle on analog and RF concepts is always a treat.