SDRmon

A terminal-first SDR monitoring and analysis toolkit for Python. SDRmon provides a full-featured Textual-based UI for exploring RF spectrum directly from your terminal.

Features

• Native SDR Backends: Connect directly to RTL-SDR without needing Python ctypes overhead. (Only RTL-SDR is supported natively so far)
• Real-Time DSP: Built-in channel manager for FM demodulation and resampling.
• Spectrum & Waterfall Displays: Fast terminal graphics rendering.
• Audio Output: Demodulate and listen to signals via PortAudio.
• Scanner: Automatically scan a frequency range and halt on active signals.
• Capture & Replay: Record full IQ bandwidth to disk and replay later precisely as received.
• Cross-Platform: Works on Windows, macOS, and Linux terminals.

Installation

You can install SDRmon directly using uv (recommended) or pip:

uv tool install sdrmon

To include optional dependencies for TUI, DSP, and Audio:

uv tool install sdrmon[all]

RTL-SDR Setup (Windows)

SDRmon uses a native C++ extension to talk to RTL-SDR hardware. You need the standard RTL-SDR DLL installed correctly:

1. Download the latest rtlsdr.dll and libusb-1.0.dll from the RTL-SDR official releases.
2. Place them in your system PATH or in the same directory you run SDRmon.
3. Make sure to use Zadig to replace the default USB driver with WinUSB.

Quick Start

Launch the interactive GUI:

sdrmon

This will open the startup screen where you can select an available SDR device, use a FakeSDR for testing, or replay a capture.

Check device and environment health:

sdrmon doctor

List available SDR devices:

sdrmon devices

Capture 5 seconds of raw IQ data (10M samples at 2MS/s):

sdrmon capture --out signal.iq --samples 10000000

Replay a capture:

sdrmon replay signal.iq

GUI Controls

Once inside the monitor screen:

• Frequency/Gain/Rate: Use the sidebar to tune frequency, change gain, and set sample rate.
• Demodulation: The Audio control panel allows setting Mode (WFM/NFM/AM), Squelch, and Volume.
• Zoom/Scale: Adjust FFT zooming and DB scaling interactively.
• Actions:
  • SCAN: Enter Scanner mode.
  • CAPTURE: Open the capture dialogue.
  • REPLAY: Browse available .iq files for replay.
  • QUIT: Exit SDRmon.

Python SDK

You can use the SDRmon components directly in your own scripts. See the examples/ directory for demonstrations of device usage, spectrum analysis, channel DSP, and PortAudio playback.

from sdrmon.backends import initialize_backends
from sdrmon.native.manager import NativeSDRManager
from sdrmon.core.settings import StreamConfig

initialize_backends()
mgr = NativeSDRManager()
dev = mgr.open("rtlsdr:0")

with dev.stream(StreamConfig(frequency=100_000_000, sample_rate=2_000_000)) as stream:
    for block in stream:
        print(f"Received {len(block.samples)} complex samples!")

License

MIT