Open Source RF Experimentation

The talk opens with an overview of software-defined radio, a design approach where most signal processing happens in software rather than fixed analog circuits. The speakers compare low-cost receive-only dongles with transmit-capable devices and explain why an inexpensive receiver is a sensible place to start experimenting.

The middle section walks through specific open projects. These include the M17 digital voice mode, a budget amateur radio transceiver kit whose oscillators and filters are controlled by a microcontroller, and the HasViolet LoRa project built on Raspberry Pi Zero hardware. The HasViolet link was tested across a river at very low transmit power. The speakers also described a fox-hunting transmitter concept, SDR Angel as a multi-mode application, the SigPi package-based distribution for Raspberry Pi, and OpenRTX, which replaces firmware on existing handheld radios.

The closing remarks stressed that hardware and software are increasingly blended in open projects, and that experimenters should stay within licensed or permitted spectrum and avoid interfering with others. The session ended with audience questions about satellite communications, emergency amateur radio support and cellular network experimentation.