A networkAnalyser has been created by [FromConceptToCircuit] using an SDR (software-defined radio) normally used for transmitting and receiving radio signals.
The Analyser works by sending a range of tones to the circuit being tested and measuring the gain (or loss) at each frequency; this measurement is labeled S21.
A second measurement, S11, is achieved by inserting an RF bridge and measuring the return loss; the overall impedance of the circuit can then be calculated.
This prototype works across the 0.1-3GHz range with a dynamic range of at least 10dB, but not all frequencies can be measured accurately.
A more directive RF bridge is required to improve these inaccuracies.
The project is open source and the Python code is available on GitHub.