New Hampshire-based RadioStack is looking to launch a piece of amateur radio equipment with a difference: the Maverick-603 is powered by free and open source silicon, built using the Efabless platform at a SkyWater fab.
"Maverick-603 is the first affordable FT8 receiver board built around an RF receiver chip that was designed using fully open source tools and fabrication," its creators explain. "It is capable of acquiring FT8 signals between 7MHz and 70MHz. With this frequency range, you will be able to receive signals from around the world with high accuracy. The use of our Low Noise Amplifier (LNA) will also give the chip the ability to amplify very low-strength signals, which is necessary for an effective FT8 receiver."
Created by Joe Taylor and Steve Franke and released in 2017, FT8 is a digital radio mode based around frequency shift keying and designed to be decodable even with extremely weak signals. The Maverick-603 is specifically tailored to that mode, working as a tunable radio receiver with a control system running on an off-the-shelf Microchip ATmega1608 microcontroller.
It's the other chip on the board that is of the most interest, however: the radio receiver itself is a custom design created by RadioStack using only open source silicon design tools, put onto silicon at a SkyWater Technologies fab using the company's open source SKY130A production design kit (PDK) and the Efabless platform. While it's not the first open source chip to reach production, thanks to the Google-funded Open MPW program, it's one of the more practical: a fully-functional FT8 receiver.
"It is difficult for open source practices to thrive in the chip-design industry, but Maverick-603 demonstrates that open source chip design can produce products that equal or surpass their closed-source counterparts," RadioStack claims. "With this project, we aim to gather interest and support, both for amateur radio and for open source chip design."
The FT8 receiver chip design is available on GitHub under the permissive Apache 2.0 license, with more information available on the Efabless project page; fully-functional receiver boards, which include the microcontroller and provide an SPI bus for control from an external device alongside USB support, are to be pre-sold via a Crowd Supply crowdfunding campaign in the near future.