X-UHF: Superhetrodyne Spectrum Analyzer

Colin Alston has made X-UHF: a low cost RF prototyping system for experimentation with VHF and UHF bands.

Colin Alston is a fan of the X-Microwave products but they were more advanced than he needed and more expensive than he could justify spending as an RF hobbyist. So, Alston set out to make a low cost RF prototyping system using a Teensy 3.5 and the Teensy Audio library. After trying out a few approaches Alston managed to make it work! He explains that he chose to “mix down to a 10khz IF, then use a Biquad filter with a 15Khz highpass stage and 0.7 Q factor. This effectively converts the FM to AM. Then to convert the AM I simply run an abs function on the stream”.

Luckily for us, Alston has published lots of details about this project, plus all the fun developments along the way. You can find the build logs over at Hackaday.io, you can take a look at the code on Alston’s GitHub, and you can find the design files for all the 3D printed components on Thingyverse.