PyVNA

Python driver library for low-cost vector network analyzers of the NanoVNA family. Supported protocol families:

• NanoVNA V1 — line-based text protocol
• NanoVNA V2 / LiteVNA — binary register protocol
• NanoVNA-X — ChibiOS shell protocol (USB CDC serial)

Requirements

• Python 3.12+
• Optional: a VNA connected via USB-serial for hardware use
• VNA devices might use the NanoVNA-X firmware for supported devices; it is preferable

Install

pip install pyvna                # core library (drivers + calibration)
pip install "pyvna[server]"      # adds the example HTTP server
pip install "pyvna[test,dev]"    # adds the test and lint toolchain

Editable development checkout:

pip install -e ".[server,test,dev]"

Quickstart

from pyvna import SweepConfig, VNAPool

pool = VNAPool()
vna = pool.get("COM5")            # or "/dev/ttyACM0"
print(vna.model)                  # identification string from the probe
vna.set_sweep(SweepConfig(start=1e6, stop=900e6, points=101))
data = vna.get_data()
print(data.to_touchstone("s11"))  # standard Touchstone RI export
pool.close_all()

Calibration (SOL)

from pyvna import (
    CalibrationPlan,
    CalibrationStandard,
    CalibrationStep,
    SweepConfig,
)

plan = CalibrationPlan(
    name="s11-sol",
    sweep=SweepConfig(start=1e6, stop=900e6, points=101),
    steps=[
        CalibrationStep(CalibrationStandard.OPEN),
        CalibrationStep(CalibrationStandard.SHORT),
        CalibrationStep(CalibrationStandard.LOAD),
    ],
)
profile = vna.acquire_calibration(plan, prompt=lambda std: print("connect:", std))
data = vna.get_data()             # S11 de-embedded with the three-term model

The profile is installed only after all standards are measured and the error terms compute and validate; a cancelled run raises CalibrationCancelledError and installs nothing. S21 passes through as measured — see the API docstrings.

HTTP server

python -m pyvna.server.main [--host 127.0.0.1] [--port 8080]

• GET /api/v1/scan?port=COM5&start=1e6&stop=900e6&points=101&trace=s11 -> Touchstone
• GET /metrics -> Prometheus text format

The server binds to loopback by default; put it behind an authenticated reverse proxy for network use.

Project layout

• pyvna/__init__.py — public API exports and package version
• pyvna/errors.py — exception hierarchy rooted at PyVNAError
• pyvna/models.py — SweepConfig, VNAData; Touchstone RI export, VSWR
• pyvna/driver_base.py — shared driver behaviour: bounded I/O discipline
• pyvna/driver.py — Driver protocol, probe factory, VNAPool
• pyvna/driver_v1.py — NanoVNA V1 line-based text protocol
• pyvna/driver_v2.py — NanoVNA V2 / LiteVNA binary register protocol
• pyvna/driver_x.py — NanoVNA-X ChibiOS shell protocol (USB CDC serial)
• pyvna/calibration.py — SOL calibration: standards, plans, profiles, error terms
• pyvna/vna.py — high-level VNA facade: sweep, scan, calibration
• pyvna/util/serial_port.py — serial port abstraction and path validation
• pyvna/server/main.py — example FastAPI server: Touchstone scans + Prometheus metrics
• tests/ — unit test suite with mock ports and fake devices

License

MIT (see LICENSE)