SDR ProTrack: Android Radio Direction Finding with RTL-SDR and Directional Antennas

Thank you to Alexandre Gellibert for writing in and sharing his new Android App, "SDR ProTrack." SDR ProTrack is a radio direction-finding app that uses an RTL-SDR and directional antenna to determine a bearing towards a transmitter.

Interestingly, Alexandre notes that this app was initially developed to track Asian hornets, a bee-killing pest. With hornet tracking, a miniature RF transmitter is attached to a caught hornet, and the hornet brings it back to the nest. RF tracking techniques can then be used to find the nest.

It's possible to determine the bearing toward a transmitter by using a receiver such as an RTL-SDR paired with a directional antenna like a Yagi. Directional antennas have high sensitivity in one primary direction and significantly lower sensitivity in all others. By rotating the antenna until the strongest signal is identified, you can establish the precise bearing angle. Typically, following this bearing will guide you directly toward the signal's origin.

Alexandre wrote in an email to us the following:

Just to let you know we just launched a new Android app compatible with RTL-SDR dongles (though mostly tested on RTL-SDR v4).

App is free to use. Advanced features (like Compass to point the signal potential source) are for premium users.

It's plug and play, easy to use, much more user friendly than SDR++.

Any feedback is really appreciated :)

If you want to know more about the project or the 2 developers behind it (we develop it in France to be able to track asian hornets that kill all the bees), please feel free to contact us.

And the Android page describes SDR ProTrack in the following way:

Unlock the power of radio tracking with SDR ProTrack!
Transform your Android smartphone into a signal-tracking powerhouse using an RTL-SDR dongle and a directional antenna. Affordable, versatile, and perfect for enthusiasts, researchers, pros or anyone tracking signals—like Asian hornets or wildlife.

★ Key Features ★

• Automatic RTL-SDR dongle recognition and connection (free)
• Spectrum Visualization (Free): View signal shapes in the frequency domain effortlessly.
• Compass (Premium): Pinpoint the strongest signal direction with precision.
• Signal Strength Display (Premium): Monitor signal power with an intuitive interface.
• Custom Settings (Premium): Adjust bitrate, sample rate, and frequency sensitivity to your liking.

★ Requirements ★

• Requires an external RTL-SDR device.
• Check compatibility: https://osmocom.org/projects/rtl-sdr/wiki

Need an RTL-SDR dongle, emitters, receptors, or antennas?
Visit our website: https://www.intuite.fr/en_GB/pricing

★ About Us ★

Intuite is a company specialized in locating Asian hornet nests. We developed SDR ProTrack to provide a robust, cost-effective solution for radio signal tracking, combining innovative technology with our expertise in signal detection.

★ Open Source Community ★

Join our mission to advance radio tracking! Our open-source library, RTL-SDR Bridge Android Lib, powers SDR Pro Track.
Contribute to development, report issues, or explore the code at https://github.com/alexandreGellibert/RTL-SDR-Bridge-Android-Lib.
Support our work and help shape the future of signal tracking!

Download SDR ProTrack today and start tracking signals like a pro!

SDR ProTrack Screenshot
SDR ProTrack Screenshot

A Video Tutorial on Setting up RTL-SDR ADS-B Reception with Dump1090 and Virtual Radar Server

Thank you to Paul Maine for writing in and letting us know about his YouTube video showing how to set up ADS-B reception with an RTL-SDR, dump1090, and Virtual Radar Server on a Windows machine. ADS-B reception is a common project for RTL-SDR users; however, as Paul notes, most of the video tutorials available on YouTube are outdated.

Paul has also been uploading other videos to his YouTube channel recently, including tutorials on GNU Radio and setting up rtl_433, so check it out if you are interested.

E11 Tracking Airplanes using RTLSDR with Virtual Radar and ADS-B

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 out the SkyRoof Software for Receiving and Tracking Amateur Radio Satellites

At the beginning of this month, we posted about SkyRoof, a new software program by VE3NEA for receiving and tracking ham radio satellites with an RTL-SDR and other SDRs.

Recently, Matt from the TechMinds channel uploaded a video on YouTube testing out SkyRoof. In the video, Matt explains the software's various sections and features, such as Doppler correction. He then goes on to demonstrate various audio voice signals being received with the software.

SkyRoof - A Brand New Satellite Tracking Software With Built In SDR Software - This is awesome!

A YouTube Review of the SDRplay nRSP-ST Networked Receiver

Over on YouTube Baltic Lab has recently uploaded an unboxing and review video of the SDRplay nRSP-ST. The nRSP-ST is the latest offering from SDRplay, and it is a networked software defined radio (SDR). This means that the SDR is designed to be mounted remotely and accessed over a network connection.

The video Baltic Lab unboxes the SDRplay nRSP-ST and then shows the setup and it receiving a voice signal from the International Space Station's (ISS) amateur radio repeater. During the test, the nRSP-ST is set up outdoors, powered via a portable battery, and connected to the network over WiFi. This shows how versatile the unit can be, allowing you to set it up in whatever location is best, without worrying about long coax runs.

He goes on to show some advanced settings, such as enabling public access, and how you can access the SDR via the SDR Connect software or simply in a browser on a PC or mobile device.

SDRPlay nRSP-ST Networked Receiver: Unboxing and Testing

HydraSDR RFOne: A New Upcoming SDR Similar to the Airspy R2

Recently, we have heard news about a new upcoming SDR called the HydraSDR RFOne, created by Benjamin Vernoux, who also worked on the design of the Airspy. The HydraSDR RFOne appears to be very closely based on the Airspy R2 design, and it has very similar specs, including a 24-1800 MHz RX range, 12-bit ADC, and up to 10 MSPS sampling rate output, giving 9 MHz of spectrum.

While HydraSDR is very similar to the Airspy R2 in design, as it uses the same main LPC4370 and the same overall design and layout, there are a few minor changes. The HydraSDR RFOne uses a Rafael R828D tuner chip, instead of the Rafael R820T2 tuner. The R828D has three input pins; however, it appears that only one pin is connected to the SMA input port. The other two ports are connected to uFL connectors on the PCB, which are inaccessible from the metal enclosure.

A second interesting feature is that it comes with a much larger enclosure that can house up to three HydraSDR boards in one. Also, a USB-C connector is used instead of the microUSB (we note that the device would still be USB2.0, not USB3.0).

Another differentiating point is that HydraSDR will be made in the USA, versus China, where the Airspy R2 is made. This may be good for US customers now that the Trump-China tariffs have been implemented. But we have recently seen that iTead, Airspy's Chinese manufacturing partner, recently opened a US store with US stock. So it seems that the retail price of the Airspy will not appear to be affected by tariffs.

HydraSDR with a Single Board
HydraSDR with a Single Board
HydraSDR with a Three Boards
HydraSDR with a Three Boards

You can find more information about the HydraSDR at https://hydrasdr.com. This is still a 'coming soon' landing page; however, if you enter your email, you will be sent a PDF file with the full spec sheet and multiple photos. Pricing for the HydraSDR does not yet appear to have been released.

Over on X, a few early reviewers have already received samples, as we can see some early tests in these posts.

HydraSDR Pinout
HydraSDR Pinout

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