Phase 4 is an open source amateur radio project. Our goal is to provide both designs and equipment for a radio that will operate with a 5GHz uplink and a 10GHz downlink. Our mission is to provide an open source implementation of DVB-S2 and DVB-S2X for both satellite and terrestrial amateur radio use. The reference design will be in GNU Radio, and a variety of radio recipes will be published. These solutions range from DIY to something you can purchase off-the-shelf. Phase 4 radios are intended to be reusable and reconfigurable, supporting payloads at GEO (Phase 4B), HEO (Phase 3E), and beyond (Cube Quest Challenge). Additionally, these radios will work as terrestrial microwave stations. Groundsats on mountaintops or towers establish a fun and flexible digital microwave experience.

The Hard Part

Developing a radio system is a big challenge. The most difficult part is the software that allows this level of flexibility. The challenges are up and down the stack, from the low-level FPGA RFNoC blocks that we have committed to help develop up to the user interface that doesn’t get in your way. This is a substantial effort that will take a wide variety of people and skillsets to accomplish.

The Easy Part

It’s a golden age! Digital communications engineering has never been as fun and full of possibilities as it is right now. There are so many powerful parts, support, research, and tools available. Take your pick ranging from a multitude of SDRs to inexpensive development boards to integrated developement environments. Books, videos, free and low-cost classes, supportive communities, and amazing clubs and organizations are literally at your fingertips. Being part of the embedded processing world right now, and especially being part of the explosions of digital communications, is an adventure well worth your time. Yes, it’s hard work, but it’s completely worth it!


Phase 4 is a project of Open Research Institute. ORI’s affiliations are listed here.

The Phase 4 project is grateful for support by grants from the following organizations: