A radio receiver is always a fun project. [Jayakody2000lk] decided that his new superheterodyne design would use an Arduino and it looks like it came out very nicely. The system has four boards. An off-the-shelf Arduino, a Si5351 clock generator board (also off-the-shelf), and two custom boards that contain the IF amplifier and mixer.
The receiver started out in 2015 without the Arduino, and there’s a link in the post to that original design. Using the Si5351 and the Arduino replaces the original local oscillator and there have been other improvements, as well. You can see a video about the receiver below.
Tuning is by a rotary encoder and the current software lets you tune from about 4.75 MHz to a little over 15.8 MHz. Of course, you could change to any frequency the Si5351 can handle as long as the mixer and other components can handle it. The IF frequency is the usual 455 kHz.
If you decide to build this yourself, the design files are on GitHub. Overall a very nice and neat design. We are always amazed how little radio architecture has changed since Edwin Armstrong’s day. Of course, we have better components, even if they aren’t meant for radio purposes.
Cool! 😎 Superhets make me feel super nostalgic.
I used to use them before direct-conversion receivers.
What a sweet little project! I really like how it makes a quite difficult subject accessible and straight-forward. Wonder if the author has made any performance measurements, for example what is the frequency response of the IF strip. Also, with an untuned front end the little thing must be prone to image reception. But I guess one can get a lot of happiness from assembling and listening to such a little receiver.
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Maybe this is how I can finally use those 200 different Russian germanium diodes I’ve been stockpiling for a while now. Quite a few of them a suitable to replace the OA90 or 1N34.
If you have a decent stack, you could try pairing two of them for a full-wave split-secondary AM detector. This gives lower distortion especially in low SNR conditions and copes better with deep modulation.
Nah, just hang on to them, some day you may really need to use them.
B^)
s/and their have/and there have/
“lets you tune from about 4.75 MHz to a little over 15.8 MHz.” That used to be prime international broadcasting ‘real estate’, but moribund nowadays.