r/sdr

For example, I can hear a radio station at 98.2 MHz but then I hear that same station at varying qualities across multiple frequencies up to 99.6 MHz

https://preview.redd.it/zb4k8344xlvg1.png?width=1891&format=png&auto=webp&s=3841e118c311ecbac7c34505ea7a94c9bddb3c61

Hey,

I’ve been getting less active in the WebSDR scene lately, but this is something I’ve been working on for a few years and wanted to finally release.

The original WebSDR by PA3FWM has been closed source for over 10 years. It’s still widely used, but because of that, people mostly end up patching around it instead of actually building on it.

I wanted to make a proper open alternative that keeps compatibility but is fully independent.

VertexSDR is a WebSDR-compatible server written from scratch in C.

Since the original is closed source, this is a clean-room style rewrite. No code was taken from it, no reverse engineering copy paste. The goal was to match behavior and features so existing setups can migrate easily, while having a fully open codebase going forward.

It uses the official WebSDR frontend, so the UI and workflow are exactly what people are used to.

This took a few years to get to this point.

My goal is and was always working with the community and bringing value.

What you get:

• Same WebSDR experience in the browser (official frontend)
• AM, SSB, CW, FM including synchronous AM
• RTL-SDR via rtl_tcp
• ALSA, TCP SDR relay, and stdin input
• Not limited to 8-bit, works with higher resolution IQ
• FFTW CPU backend and optional Vulkan or VkFFT GPU backend
• Multi-band with config reload
• IQ balance correction, noise blanker, per-frequency EQ
• Logbook and chat
• Registers to websdr.org and sdr-list.xyz

What’s improved:

• Fully open source (LGPL)
• Clean codebase, no legacy patches
• Fixes issues like raw IP address leaking
• Adds sync AM, bandplan support, and flexible input (stdin, etc)
• Not tied to a specific SDR or format
• Meant to be extended instead of everyone maintaining their own private versions

Quick start (Debian/Ubuntu):

sudo apt install build-essential libfftw3-dev libpng-dev libasound2-dev libssl-dev xxd
make
edit websdr.cfg
./vertexsdr

Open http://localhost:8901

RTL-SDR example:

rtl_tcp -a 127.0.0.1 -p 1234 -f 10100000 -s 2048000 -g 30

In websdr.cfg:

!rtlsdr 127.0.0.1:1234

stdin example:

rx_sdr -f 10100000 -s 2048000 -g 30 - | ./vertexsdr

Current state:

It works and people are running it, but it’s still beta. Needs more testing across hardware and different setups.

The goal is to give the community a real open base instead of everyone running slightly different patched versions.

Binary release for x86 is available. More to come.

Links:

• https://github.com/Steven9101/VertexSDR
• https://forum.sdr-list.xyz/

If you try it, feedback and bug reports are very helpful right now.

If you find it useful and want to support development, you can star the repo on GitHub or donate, both links are on the project page.

https://preview.redd.it/hos0nhl0kkvg1.png?width=1198&format=png&auto=webp&s=4f72d47672ff19625bcdc26ef9e87f8b45abae9b

Been working (mostly vibe coding, not going to lie) on this for a while and figured this community would appreciate it. It's a distributed SDR-based signal detection and triangulation system that streams everything to ATAK as CoT.

What it does:

• Detects radio emissions across 30+ signal types: PMR446, FRS, Marine VHF, TETRA, P25, keyfobs, TPMS, GSM/LTE, ADS-B, AIS, POCSAG pagers, BLE (including AirTag/Find My tracking), WiFi probe requests, drone RemoteID, LoRa/Meshtastic, ISM-band devices, and more
• Distributed sensor nodes report RSSI from known GPS positions, 3+ nodes triangulate emitter locations via multilateration
• Streams detections to ATAK as CoT markers in real time, aircraft, vessels, drones, vehicles, RF emitters all show up on the map with appropriate icons
• Generates RF activity heatmaps as KML overlays for ATAK
• Tracks device movement trails as CoT polylines
• Cross-signal device correlation (finds clusters of devices that always appear together)
• Voice interception with Whisper speech-to-text on PMR/FRS/Marine channels
• Modulation classification (FM, OOK, FSK, PSK, QAM, OFDM, no ML/GPU needed)

How it works:

• Central server (pelican case) with wideband SDRs continuously scans all bands
• Lightweight sensor nodes (~$80 each: RTL-SDR Blog V4 + GPS + Raspberry Pi zero) distributed across the area (stations or in operators backpacks)
• Short-burst signals (keyfobs, TPMS, pagers): nodes scan autonomously, triangulation via post-hoc correlation
• Long signals (voice, GSM): central detects and tasks nodes to tune and measure RSSI
• Everything logs to per-session SQLite databases, so you can do post-hoc analysis too

Web dashboard, shows live detections with category tabs (Voice, Drones, Aircraft, Vessels, Devices, Cellular...), a Leaflet map, device tracking, correlation analysis, and audio playback with transcripts for voice intercepts. Can also run standalone against historical .db files.

There are still some missing features, like the server to node coms (planned over Meshtastic), hopefully I will be able to implement it as soon as the rest of the hardware arrives.

Hardware:

• Multiple RTL-SDR Blog V4 (~$30) for most RF
• Alfa USB WiFi adapter for monitor-mode WiFi/drone detection and BT
• HackRF One for wideband, TX tests and further plans
• GPS module
• Server runs on Raspberry Pi 5
• Nodes are planned to run on Raspberry Pi zero
• Power hubs

Stack: Python, no cloud dependencies, everything runs locally. TAK server integration via client certificates.

Code is on GitHub. Happy to answer questions or hear ideas.

https://github.com/arall/sigint

How can i run the rds blocks in vs code claude says i only can on Linux i'm using windows so the rds is not giving me clear output