Tagged: rtl-sdr

OnAir Adds Decoder Support for Almost Every Signal

Just last week we posted about OnAir, a new open-source program that started out as an easy-to-use digital and analog TV decoder for software-defined radios. It also had support for a few digital modes like ADS-B, GNSS and DMR.

In the last week, with the obvious help of Claude AI, OnAir has added experimental support for almost every single analog and digital signal and application out there. Support ranges from digital voice modes like P25 and NXDN, to HF digital modes like HFDL, to aircraft signals like ACARS and VOR/ILS, to ocean radar, to a radio astronomy integrator, to satellite decoders like Iridium and Inmarsat, to cell tower metadata decoders to Wi-Fi and many many more.

Obviously, with these decoders all being vibecoded so quickly, there is no guarantee yet that they will all work as expected. However, we did give some decoders in the program a test with an RTL-SDR. A DMR control channel was successfully decoded, and it read the calls; ADS-B showed aircraft; LTE PCI values were detected with the LTE decoder; and POCSAG messages came in cleanly.

From our own experience with Claude, Opus 5.5 is very capable of vibe-coding decoders, so there is a high chance that most, if not all, of the decoders implemented in this software will work. 

OnAir Updated to Add Almost Every Decoder Possible
OnAir Updated to Add Almost Every Decoder Possible

AI Disclaimer: This software was coded with Claude AI.

SDR– Updated to V2.2: Many New Decoders, Tools and KrakenSDR Direction Finding and Beamforming Support Added

Last month we posted about the release of SDR-- (SDR minus minus), an open-source app that lets you visually wire together a receiver on a canvas. Since that time, Julian, the developer of SDR--, has been busy adding support for many decoders, various tools, and improving performance. Julian has also added KrakenSDR support, with radio direction-finding and beamforming blocks. Julian shares the following update for SDR-- V2.20:

New Decoders

  • Aviation and satellite: VDL2, HFDL, Inmarsat Aero and STD-C, Iridium, Drone Remote ID, 406 MHz beacons
  • Voice: TETRA, Tetrapol, GSM downlink, DECT, D-STAR, FreeDV, NXDN, dPMR
  • Data: LoRa (LoRaWAN, Meshtastic, MeshCore), ISM sensors, End-of-Train, DSC, BLE, Wi-Fi survey
  • Weather: NOAA APT, Meteor LRPT, WEFAX, radiosondes with landing forecast
  • Broadcast: DVB-T/T2, DVB-S2X, DAB packet mode, DRM with xHE-AAC

Coherent and mobile

  • Direction finding, beamforming and passive radar on the KrakenSDR
  • An iOS app with CarPlay for DF while driving is in TestFlight. Android is coming soon.

Hardware

  • Native Support: KrakenSDR, RTL-SDR Blog V4 Lite, AntSDR, PlutoSDR, SDRplay, Airspy, bladeRF and ESP-SDR
  • NanoVNA and antenna rotators
  • rtl_tcp and ADS-B Beast output for other apps

Tools

  • A satellite node with Doppler correction, plus a map with footprints and tracks
  • A spectrum monitor that classifies signals automatically, and a scanner with priorities and lockouts
  • Antenna calculator, noise figure, PER tester, SID monitor
  • Audio denoise, call recording, and a decoder log grouped by station
  • Event outputs: CSV, desktop notifications, PostgreSQL, InfluxDB

App

  • A redesigned UI with a unified look for every node
  • Multi-user editing, remote access from a browser, built-in HTTPS
  • An MCP server, so an AI assistant can build and tune a canvas

Performance

All measured on an M4 Max, full results at https://sdrmm.com/benchmarks:

  • DSP against GNU Radio:
  • FIR is 3.5x faster
  • NCO is 3x faster
  • FM demod is 4x faster
  • DDC is 1.6x faster
  • A 4096-point FFT is 1.6x faster than FFTW
  • Decoding rate in noise (48 trials per decoder across an SNR range):
  • ADS-B: 68%, against 56% for readsb and 50% for dump1090-fa
  • POCSAG: 73%, against 50% for multimon-ng
  • DMR: 81%, against 60% for dsd-fme
  • NXDN: 67%, against 23% for dsd-fme

(feel free to verify yourself with cargo xtask compare dsp)

The speed comes from hand-written SIMD kernels (NEON, AVX2, AVX-512), one shared downconversion for all channels on a radio, and a DSP path that never locks or allocates. The noise gains come from decoding IQ directly with
coherent receivers and soft decisions.

SDR-- Screenshot
SDR-- Screenshot

AI Disclaimer: This software is likely to be AI-assisted or vibe-coded.

SDR Signal Analyzer: A Windows Spectrum Analyzer for HackRF, RTL-SDR and tinySA

Thank you to RTL-SDR.COM reader Sunny for writing in and submitting a program he's found called 'SDR Signal Analyzer'. This spectrum analysis program lets you use a HackRF, RTL-SDR, or tinySA to scan the entire spectrum between 1 MHz and 6 GHz. Like other spectrum analysis software that offes wideband sweeps, it does this by rapidly returning across the live spectrum, stitching together a wideband picture of the spectrum.

The software also offers IQ demodulation of the common modulation schemes, as well as CTCSS decoding and video decoding from FPV and PAL analog video systems. 

The software is free; however, a pro version exists that supports the BladeRF, PlutoSDR, and FobosSDR, and adds markers, OBW, ACPR, calibration in dBm, a scanner mode, a table, neural network signal classification, and other features. The pricing of the Pro version is only available on request.

The program appears to be open source under LGPL-3.0; however, the website notes that you will need to contact them for the source code.

SDR-SA Screenshot
SDR-SA Screenshot

AI Disclaimer: While the authors do not disclose it, it is our opinion that this software may be coded entirely or with the help of AI.

OnAir: A Digital TV and DAB Decoder for SDRs

Thank you to Kristijonas for writing in and sharing with us his project, OnAir. OnAir is an easy-to-use digital TV decoder for DVB-T2, DVB-T, ATSC 1.0, ATSC 3.0, ISDB-T, and a digital audio decoder for DAB / DAB+ and FM Radio. It also supports Analog TV modes such as PAL, SECAM, and NTSC, and data modes like ADS-B, GNSS (GPS, GLONASS, BeiDou), and DMR.

It supports various wideband SDRs, including HackRF, PlutoSDR, BladeRF, LimeSDR, USRP, Airspy R2, and SDRplay. RTL-SDRs unfortunately do not have enough bandwidth to decode digital TV channels in SDR mode, but the software still supports RTL-SDRs for narrowband signals.

The software is easy to install, with an installer .exe being available for Windows, a .deb file for Debian Linux, and a .dmg file for macOS. 

OnAir Screenshot
OnAir Screenshot

AI Disclaimer: This software lists Claude as a contributor.

ESPsoup: Turn an ESP32-C5 into a 2.4 & 5 GHz Pocket Scanner with a Connected Phone or PC

Thank you to Peter Holzhauser for writing in and sharing with us his latest open-source project, 'ESPsoup'. Peter has written in previously to share his Android app, V2X2MAP, which detects and plots vehicle V2X (car-to-car) communications used by some modern cars. His new project, ESPsoup, combines an ESP32-C5 and a connected PC or phone into a fully featured scanner for the 2.4 GHz and 5 GHz bands.

ESPsoup has various features including a live spectrum view up to 80 MHz wide, a sweep mode to monitor larger bandwidths, a GPS-enabled heatmapping tool, Bluetooth analysis tools, an AirTag detector, WiFI analysis tools, a car-to-car V2X monitor, a smart home sensor reader, a drone remote ID detector, a microwave oven detector, and an analog FPV video demodulator and display.

The website notes that if you want to monitor multiple FPV drone video channels, up to eight ESP32-C5s have been tested to work together on a single USB hub connected to a PC.

Peter notes that he is planning to add RTL-SDR support to ESPsoup in approximately two weeks, so keep an eye out on their website for updates.

ESPsoup screenshots from a mobile device.
ESPsoup screenshots from a mobile device.

ChronAlert: Live Dashboard for Radio, Weather, Alerts with RTL-SDR Integration for APRS, ADS-B and AIS

Thank you to Danny from brokensignal.tv, who wrote in and shared the release of his new project, 'ChronAlert'. Danny describes ChronAlert as "a free PC-based live dashboard for radio, weather, alerts, and other live information". 

ChronAlert appears to be a situational awareness dashboard that combines multiple live feeds into one screen. It includes feeds like weather and emergency, ham radio & propagation, hazards & infrastructure, and local radio & tracking.

On the local radio side, we see that RTL-SDR is supported for receiving and tracking aircraft and ships via ADS-B and AIS, and for receiving APRS messages.  The dashboard also supports Meshtastic radios, allowing users to see heard Meshtastic nodes and messages.

ChronAlert is free at the basic level, which allows 2 saved panels and 1 watch zone. A one-time fee of US$39.99 unlocks 10 panels and 10 watch zones, as well as various other features.

If you want more information, Danny has also published a detailed article with screenshots about ChronAlert on his blog.

ChronAlert: Weather, Ham Radio, Alerts & More in One Free Dashboard

OFFgrid-SDR: A Fully Offline RTL-SDR Receiver Program in a Single Index.html File

Thank you to Richard Didd for submitting his new software, 'OFFgrid-SDR', a fully offline RTL-SDR receiver program in an installer-free, single index.html file.

The OFFgrid-SDR program runs in any modern WebUSB-compatible browser, can demodulate common modulation types, and includes a spectrum and waterfall display, plus RDS, weather fax, and Morse code decoders. No internet connection is required to run it in the browser.

The program's advantage is that you can put the index.html file on a USB drive and use it portably on almost any machine with a browser. However, Windows users will still need to have installed the WinUSB drivers via Zadig first, and Linux users will need to blacklist the DVB-T drivers from taking over the dongle. macOS and Chromebook should just work without any additional steps.

The code is entirely open source and available on GitHub. More information about the project can be found on the project's GitHub.io page.

OFFgrid-SDR Screenshot
OFFgrid-SDR Screenshot
OFFgrid-SDR Demonstration with RTL card and Demo Mode

FernSDR: An Open-Source WebSDR Server

Thank you to 'magicint1337' for writing in and sharing with us a new program he's created called FernSDR. The author writes that FernSDR is an open-source WebSDR server rebuilt from scratch, based on feedback from WebSDR operators. It replaces his two previous programs, NovaSDR and PhantomSDR, the latter of which we covered in 2024.

A WebSDR program like FernSDR allows users to set up an SDR receiver on a remote device, such as a Raspberry Pi or PC, and access that SDR's data from anywhere in the world via a network connection. The author explains why FernSDR stands out:

What's different: a single binary with no dependencies and a one-line install on any Linux, an admin panel for everything (bands, updates with rollback, modules), day/night band switching by sunrise at the station, and modules for RTL-SDR (incl. Blog V4), RX-888 MkII and SDRplay, plus an FT8 decoder with PSK Reporter spots. In my lab tests against ten other WebSDR servers it had the lowest delay and memory use; the method and raw data are public.

A live demo of FernSDR is available at demo.fernsdr.org. The code is open-source and available on GitHub.

FernSDR: A New WebSDR Server
FernSDR: A New WebSDR Server