Using a 75 Year old Marconi CR100 Radio to Control an SDRplay RSP

Over on YouTube Jon from SDRplay has uploaded a video showing how he’s used the knobs and interface from a 75 year old Marconi CR100 analogue radio to completely control an SDRplay SDR. This allows you have the feeling of tuning a vintage radio with the old fashioned knobs, whilst enjoying the features of a modern SDR.

Within the old radio enclosure they’ve managed to fit in a full Acer mini computer which runs the RSP on HDSDR. To allow the main tuning knob on the Marconi to tune the SDRplay they’ve used an Arduino controller, and an optical shaft encoder. As they intend for their hybrid to be completely keyboard-less, they’ve also added two UP/DOWN buttons to jump up and down the spectrum, buttons to choose the demodulation mode, and a new knob to control the zoom setting in HDSDR.

The project was sponsored by RS components and is intended to be used in the November 2016 Electronica event in Munich as an exhibit that celebrates the 80th anniversary of the expo. The idea is that the SDRplay-Marconi hybrid combines radio technology which would have been around during the first Electronica expo’s as well today’s modern SDR technology. There is a write up of the project available on the RS components designspark website.


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This is pretty cool, and I guess it’d be easy enough to rebuild/restore the set if enough original parts came along if desired. Good job!


Jon, The radio was completely DOA to begin with. It was purchased broken and re purposed for this project.

Berie, Actually I didn’t use any library. Its all from scratch.

All the best


Man that is truly a lash-up, cannot see the point of wrecking an old radio like that and nailing in some modern components – bit like a broken pencil…..point less.


Very interesting.

I’m guessing that the code used to emulate a keyboard(and/or mouse) on an Arduino was using a library like the following:

And the reason that they used HDSDR, instead of SDRplay’s SDRUno, is because it has extensive keyboard shortcuts for basically everything. Where as SDRUno basically has very few keyboard shortcuts at a guess, and would require some complex mouse coordinate calibrations that would change depending on the dimensions of the display screen. It is always best to choose the path of least resistance when doing anything half way complex.