Category: Applications

A New Radiosonde Decoder and Tracker Program for Windows and RTL-SDR

Thank you to Mario Ančić for informing us about his recently released software, "Radiosonde-decoder-and-tracker-for-Windows". As the name implies, this is Windows only software that can decode and track radiosondes.

A radiosonde is a lightweight instrument package typically carried by a weather balloon to collect atmospheric data such as temperature, humidity, pressure, and GPS position. It transmits this data back to the ground via radio signals. Using an RTL-SDR or another software-defined radio (SDR) along with appropriate decoding software, hobbyists or researchers can receive, decode, and visualize these signals.

Mario has shared the following information about his software:

The program supports four types of sondes: RS-41, M10, M20, and DFM (PS-15, DFM09, DFM17 tested).

The program is designed to run without any additional installations or software, except for the ZADIG driver for RTL-SDR (RTL2832). It uses RTL-FM for SDR reception and the popular open-source RS1729 for decoding. Decoding is also possible via the audio input (using Virtual Audio Cable and SDR# or SDR++ or any other SDR software).

The received data can be sent to servers such as Radiosondy, Wettersonde, or other APRS-based weather radiosonde servers. Optionally, the data can be sent to two servers simultaneously.

Further information and the downloadable program are available in the Release section on the page:
recently released software, "Radiosonde-decoder-and-tracker-for-Windows"

The program is intended for 64-bit Windows OS (Windows 7 or newer) and is Freeware.

We note that the software is freeware; however, it does not appear open source, as no code has been shared.

Radiosonde Decoder and Tracker Screenshot
Radiosonde Decoder and Tracker Screenshot

TechMinds: Testing the SDR++ Brown Fork with Built-In DSD and Remote KiwiSDR Support

Over on YouTube, Matt from Tech Minds has uploaded a video in which he demonstrates and tests an unofficial fork of the popular SDR++ software called "SDR++ Brown."

SDR++ Brown has some unique features such as the ability to connect to remote KiwiSDR WebSDRs directly within the UI, built-in FT8 and FT4 decoders with PSK reporter, a built-in DSD decoder allowing for DMR, P25 and NXDN to be decoded directly in the software, Hermes Lite 2 support, and various Android UI improvements for small screens.

Matt also notes a few bugs with the software, such as PSK Reporter and Multi-WebSDR waterfall display features being broken.

Over on X, Alexandre Rouma, creator of the original SDR++, has expressed concern about this fork. He notes that this is an unofficial fork that is not up to his standards and that support requests for SDR++ Brown should not be made to him. Instead, support requests should be made directly to the fork owner, Sanny Sanoff.

SDR Plus Plus - Brown Edition Adds New Features Including DSD!

RadioTransciptor: Real Time Radio Speech to Text Transcriptor using AI

Thank you to user theckid from our forums for submitting news about the release of his latest project called "RadioTranscriptor". RadioTranscriptor can be used for real-time speech-to-text transcription, which is especially useful when you want to log radio communications and create searchable text files. theckid writes:

I just released an open-source Python tool that does real-time radio transcription using OpenAI’s Whisper model. It uses voice activity detection to only transcribe when speech is actually happening — great for monitoring radio chatter or voice nets on HF/VHF/UHF.

It’s designed for use with SDRs (Software Defined Radios) where audio is routed into the script. It performs:

  • Live microphone or SDR audio monitoring
  • RMS-based voice activity detection (VAD)
  • Automatic transcription with Whisper
  • Timestamped logs saved per session
  • It’s perfect for:
  • Ham radio operators
  • Emergency scanners
  • Broadcast archiving
  • Signal analysis enthusiasts

The AI model used is Whisper by OpenAI. The software uses NVIDIA CUDA GPUs when available and defaults back to CPU if none are available.

RadioTranscriptor Block Diagram
RadioTranscriptor Block Diagram

SDR-Sharp Converter: Convert SDR# Frequency XML Lists to SDR++ Format and Vice Versa

Recently, we've seen news about the release of a new Windows program by "Majic Mushroom" called SDR-Sharp Converter. This simple software converts SDR# XML Frequency Lists to SDR++ format and vice versa. It is helpful if you use both programs and want to maintain identical frequency lists.

SDR-Sharp Converter Screenshot
SDR-Sharp Converter Screenshot

Hackaday Supercon 2024: Tracking Down Radio Transmissions

Talks from the Hackaday Supercon 2024 conference have recently been uploaded to YouTube, and one interesting talk by Justin McAllister and Nick Foster is about tracking down radio transmissions.

The talk focuses on using SDR hardware such as the RX888, RTL-SDR, and Airspy devices combined with directional antennas for radio direction finding. Interestingly, they also discuss using ultrasonic microphones to find power line noise from bad transformers or insulators. The talk also focuses on ensuring that your SDRs receive real signals and what noise might look like on the spectrum.

This talk provides a comprehensive guide to identifying and locating radio transmitters. Learn about practical techniques, common tools, and methodologies from decades of combined experience finding, squashing, and mitigating against radio frequency interference.

Supercon 2024: Justin McAllister and Nick Foster - How to Track Down Radio Transmissions

SkyRoof: New Ham Satellite Tracking and SDR Receiver Software

Recently VE3NEA has released a new Windows program called "SkyRoof". SkyRoof is both a satellite tracking and SDR receiver program. It supports the RTL-SDR as well as Airspy and SDRplay devices.

The software is designed for tracking and receiving ham radio satellites, and it can provide detailed information about all ham satellites, tracking them in real time, and provide pass prediction. It also shows a skymap and SDR waterfall display. The receiver software supports demodulation of SSB/CW/FM, and it automatically compensates for doppler. It can also interface with antenna rotators that support hamlib.

SkyRoof Satellite Tracking and SDR Receiver Software Screenshot
SkyRoof Satellite Tracking and SDR Receiver Software Screenshot

Over on YouTube Johnson's Techworld has also recently uploaded a video showing him testing out Skyroof, which may be of interest to some.

Brief review of SkyRoof, the latest satellite tracking software!

Open-Source 0.1–3 GHz Network Analyzer using ADALM Pluto SDR

Thank you to RTL-SDR.COM reader MAKA for writing in and sharing his project with us, an open-source 0.1 - 3 GHz network analyzer using an ADALM PlutoSDR and a $15 RF bridge. The system allows you to measure S21 (insertion loss/gain) and S11 (return loss) with real-time visual feedback. MAKA writes:

Key features include:

  • FFT-based FIR filter for precise measurements
  • Simple S21 and S11 calibration workflows (LOAD & OPEN)
  • Real-time plots with smoothing and raw-data toggles
  • Interactive markers for easy dB/frequency annotations
  • Automatic export of calibration data to .xlsx for offline analysis
  • Fully open-source

The complete open-source code for the project is available on GitHub at  https://github.com/fromconcepttocircuit/pluto-network-analyzer

Over on his YouTube channel, MAKA has also uploaded a video demo and walkthrough.

RF Bridge Turns Your Pluto SDR into 0.1-3GHz Network Analyzer(Pt.1: S11/S21 Fund. & Filter Test)

Pluto Network Analyzer Pt. 2: S11 Calibration, Python Code & RF Bridge Performance

AEDA: Crowd Sourced RTL-SDR Spectrum Analysis and TDoA Direction Finding Platform

Recently, we've seen posts on X about a new service called "AEDA" (Advanced Electromagnetic Detection Application). This crowd-sourced web service utilizes RTL-SDR dongles as the RF reception hardware. The software can use multiple RTL-SDRs distributed around a city area for spectrum analysis and TDoA (Time Difference of Arrival) radio direction finding.

The service uses RTL-SDR dongles connected to Raspberry Pis as RF monitoring hardware. In the web UI, a user can initiate a spectrum scan using any of the distributed RTL-SDR nodes available to them. It can also automatically detect popular modulation types such as WBFM, NBFM, DMR, and P25.

A user can also initiate a TDoA scan to localize the source of a particular signal. This requires at least three RTL-SDR nodes to be distributed with good geometry around the signal source. The service synchronizes time via external wideband noise-like signals such as TV signals, cell towers, and DAB, so one of these signals must be available to be received by all RTL-SDRs used in the TDoA calculation.

For now, the service and features appear to be free. However, it looks like they will monetize the platform in the future by renting the crowdsourced RTL-SDR nodes to companies and persons that need to do band studies, radiolocation, and interference detection. They also hope to pay node owners for any time the nodes are rented.

More information about the AEDA service is available on their documentation page.

AEDA Scan with Modulation Detection
AEDA Scan with Modulation Detection
AEDA TDoA Hyberbolas from Three Distributed RTL-SDRs