If you time-warped back to sometime around the 1970-80s and showed this article to a bunch of electronically-minded people, ignoring the SDR stuff, they'd take a quick look and say something like 'um - yeah' and move on.<p>This type of one transistor radio is/was a really common circuit and probably the vast majority of hobbyists built something similar - all without having to run a simulation first. I can recall spending a happy afternoon as a boy in that time period sorting through my box of stuff, pulling out a DL96 vacuum tube and knocking up a MW/SW receiver. I also left countless 'cats whisker'/crystal set (germanium diode) receivers and ZN414-based creations in my wake.<p>The one thing I get out of that article is that technology has moved so far that we now get impressed by the simple stuff - the fundamentals - it's becoming a lost art.<p>I'm not sure I've picked the best modern analogy - but perhaps think of showing someone a USB flash stick and saying "...and when you plug it in to your PC YOU CAN SAVE FILES ON IT".<p>I think this is where I put "Plus ça change..."
Nice. Some comments:<p>- he used simulation up front. This is a great thing. Some more detail would have been nice. I tend to design small circuit components up front on paper with a good old fashioned calculator then simulate in LtSpice. It kills a lot of frustration and things you've forgotten about. However it doesn't always work out as SPICE can't deal with parasitic inductance and capacitance easily without adding primitives to the net. This kills you after a few MHz.<p>- The art of electronics is a terrible book IMHO if you want to learn electronics. Even as a reference its not great. It's disjoint and poorly written. Better bet is the ARRL handbook even if you don't do RF stuff. The material is wonderful in that book. Being American though, it is undergoing a transition to SI units though so its a little inconsistent in the maths with random multipliers here and there.<p>- nice to see something without a microcontroller in it and some manual work (coil winding).<p>I still wish all electronics was at this level. Much more fun.
I've been getting into electronics lately and really loving it! My inspiration was my new Atreus keyboard[1] (first one ever sold!) and the epiphany while playing Minecraft that making your own (useful) stuff is tons of fun and super rewarding. And it doesn't have to be computer programming anymore!<p>So I booked it to Radio Shack and bought the Make: Electronics book and the accompanying kit. (I could have scoured for the individual parts, this book lists them and recommends it, but it was a nice convenience to have a pre-made kit by the same company, and presumably the same author.) And so far I've only learned about resistors, capacitors, and other basic circuitry, and it's a bit math-heavy, but it's really exciting!<p>I also have a serious electronics project in mind that acts as really good useful motivation. It's a toy that's probably relevant to HN, and if I ever accomplish it, I plan to share it here.<p>Hobbyist electronics is really fun, and so far I recommend it! (That said, I have no ambitions about inventing the next great CPU or memory chip -- you probably need decades of college-level education and experience on this to be able to innovate at any serious level these days.)<p>[1]: <a href="http://atreus.technomancy.us/" rel="nofollow">http://atreus.technomancy.us/</a>
This is nice. Even with all of the other objectively more impressive technology we use on a daily basis, simple radio circuits still seem like magic to me.<p>If you would like to play with a "one transistor" <i>receiver</i>, check out the Armstrong regenerative receiver. This circuit uses a single gain element as tuned oscillator/RF amplifier. The output is inductively coupled back in to the circuit for re-amplification. Since the circuit is tuned, this increases selectivity as well as gain. See:<p><a href="http://en.wikipedia.org/wiki/Regenerative_circuit" rel="nofollow">http://en.wikipedia.org/wiki/Regenerative_circuit</a><p>Edwin Armstrong invented this when he was in college and vacuum tubes were quite expensive. One gain element handles oscillation, amplification, and demodulation for obvious economy. Despite this, performance is quite good.<p>The ARRL published an easy-to-build transistorized version a while back: <a href="http://www.arrl.org/files/file/Technology/tis/info/pdf/0009061.pdf" rel="nofollow">http://www.arrl.org/files/file/Technology/tis/info/pdf/00090...</a><p>This circuit is much harder to tune than it is to build. Once you master the steady hand action required (and learn not to move once you find a signal), you can easily pull in overseas shortwave broadcasts with a wire antenna.<p>Here's a short audio clip of me tuning my version of the ARRL regen receiver across a shortwave broadcast band:<p><a href="https://dl.dropboxusercontent.com/u/2541109/regen_tune.mp3" rel="nofollow">https://dl.dropboxusercontent.com/u/2541109/regen_tune.mp3</a>
Don't really understand the fuss, here.<p>Better articles can be had from old issues of Popular Electronics, and you'll actually be able to listen to it <i>on your radio</i> at the actual 90-100MHz bands.
Except that it isn't actually a radio but an oscillator that you <i>could</i> use to build a radio (by mixing the output of the oscillator with some input signal that you want to demodulate, and then to use the LF output of the mixer, aka the difference frequency).<p>But the article doesn't do that, and then goes off to show how you can turn this oscillator into a primitive (unmodulated, so only a carrier wave) transmitter.<p>(fun thing to do: wind that coil from thinner wire and demonstrate the microphony effect by talking to the coil, or glueing a plastic toothpick to it and a membrane to make it more sensitive).<p>If you really want to build a single transistor radio:<p><a href="https://www.google.com/search?client=ubuntu&channel=fs&q=single+transistor+radio&ie=utf-8&oe=utf-8" rel="nofollow">https://www.google.com/search?client=ubuntu&channel=fs&q=sin...</a><p>Shows plenty of results, one of which is the article linked here.
This isn't the simplest radio (or oscillator) you can build. To get the nearest AM-station, simply put a resistor, an a diode together and attach 20 m of wire and an earphone on its side. Voila!