Thank you to George (gbozo), who has just released no-sdr (named from No(de)-sdr), a new open source multi-user WebSDR for the RTL-SDR written in Go and node JS. A WebSDR allows users to run an SDR remotely and access it over a local or internet network connection. This is useful for bringing an SDR closer to an antenna, instead of running a long, lossy coax cable, and for sharing SDRs among multiple networked users.
The no-SDR software runs on x86 or Raspberry Pi, is Dockerized, and supports multiple RTL-SDR dongles being connected at the same time. On the DSP side, it currently implements WFM (stereo + RDS), NFM, AM, AM Stereo (experimental stereo C-QUAM), USB, LSB, CW, and raw IQ, with digital decoders like ADS-B, AIS, APRS, POCSAG, FT8, and WSPR planned. There is also an "Identify Song" button that uses the Audd API to ID currently playing tracks on WFM, NFM, and AM.
George also points out that he's implemented an innovative lossless FFT codec with a very high ~10:1 compression ratio, as well as the Opus codec for audio. The result is a 12-15 kB/s transmission rate with a 12 FPS FFT with 8192 bins and AM demodulation compressed audio.
Thank you to qewer33, who has written in to share the release of his new Terminal User Interface (TUI) program for RTL-SDR and HackRF SDRs. The program is called sdrrat, and it provides a complete TUI with FFT graph, waterfall spectrogram, VFO, and basic WBFM/NBFM/AM demodulation.
qewer33 notes that the software is built with Rust, Ratatui, and FutureSDR and is completely free and open source. The code is available on GitHub.
sdrrate: TUI based SDR software for RTL-SDR and HackRF
Thank you to Gary Schneider from workingwithwildlife.org for writing in and submitting news about the release of his Android App called "SDR Direction Finder (RTL-SDR)" which currently costs US$9.99. Gary is a wildlife conservationist who has been using RTL-SDRs and his Android app to track animal beacons in the wild. Gary writes his story best:
I run a conservation project in South Africa conducting wildlife monitoring, and I’ve spent the past 7 years out in the field tracking wildlife. To make tracking more practical and affordable for researchers and NGOs, I’ve spent much of my time outside of fieldwork developing an Android app to replace traditional receivers, and I’ve recently published it on the Google Play Store.
While other apps exist, I’ve found them practically too difficult to use in field conditions and very limited in range. My focus was maximizing VHF range while keeping the interface simple.
By using the app’s custom IQ filter settings with an RTL-SDR V3 and LNA combo, my old spare Xiaomi phone now outperforms my $1,200 Comm Spec R-5000 receiver. The most challenging part of development was optimising the high-resolution waterfall to run smoothly at a high sample rate without any stuttering on low-end devices.
I added a built-in mapping feature to log bearings and automatically calculate estimated signal locations. The map also allows users to import their own custom KML/KMZ files. This has been incredibly helpful for me to quickly locate my tracked animals, and to subsequently export my data for further analysis. The waterfall makes it easy to handle signal drift or monitor multiple collars simultaneously (e.g. when I’m searching for a pack of African wild dogs which might have two or three working VHF collars fitted).
While wildlife tracking here is exclusively CW in the 148–152 MHz range, the app isn't limited to this. It also supports AM, NFM, WFM (Mono/Stereo), LSB, and USB across the full range.
Even though I developed this with wildlife tracking in mind, it should work equally well for falconry, fox hunting, or simply for general SDR enthusiasts.
As most people will be aware, it is not currently possible to connect an RTL-SDR dongle directly to an Apple mobile device. So the app is designed to be used with an instance of rtl_tcp running on a Mac, PC or maybe a raspberry pi.
It is also possible to install the app directly on an Apple Silicon Mac, so that is one with an M1, M2, ... etc. In that situation obviously rtl_tcp can be hosted on the same Mac too if needed.
Anyone needing help with this app or any of our existing Android SDR apps should contact [email protected]
For comparison, the Android version is available here:
Back in June 2025, we posted about SDR ProTrack, a radio direction-finding app that uses an RTL-SDR and directional antenna to determine a bearing towards a transmitter. Alex has recently written in to note some major updates to the app.
He notes that the app has been redesigned for user-friendliness and to be as relevant as possible for signal-tracking purposes. The main upgrades include:
New hardware compatibility: SDR Lime Mini & Airspy now supported.
Enhanced signal & pulse detection
New track states, UI and in-app guidance
Now available in 14 languages
Hunt sharing on social media with pictures and map included
Thank you to Matt Cheramie, who wrote in to let us know about his new software called GopherTrunk, a new RTL-SDR compatible radio scanner that follows digital trunked-radio voice calls and decodes them into audio. Gopher Trunk runs on a pool of RTL-SDR dongles and ships as a single ~10 MB static binary for Linux, macOS, and Windows. There are no C dependencies, so neither librtlsdr nor libusb are required at build or runtime, which makes deployment on a fresh machine or Raspberry Pi very straightforward.
On the protocol side, GopherTrunk handles control-channel decoding for P25 (Phase 1 and 2), DMR, TETRA, NXDN, Motorola Type II, EDACS, LTR, MPT 1327, dPMR, D-STAR, and YSF. The voice path is written in pure-Go and implements IMBE and AMBE+2 vocoders directly, removing the dependency on external DVSI or mbelib. The interface is terminal-based, but also includes a full browser-based operator console. There is also a configuration importer that parses RadioReference.com PDF exports and CSV bundles straight into the daemon config.
Matt notes that while the engine is running end-to-end, he is looking for SDR enthusiasts to test it against real-air captures to help refine the on-air FEC layers and vocoder audio levels. Prebuilt releases and the quick start guide are available at gophertrunk.org/downloads, and the full source is on GitHub. Feedback and bug reports are very welcome if you give it a try.
GopherTrunk: A New Digital Trunking Scanner for RTL-SDR written in Pure-Go
The RTL-SDR Blog V4 has been a very popular product that we released back in August 2023. Back then, it was released as a 'limited edition' product because the Blog V4 relied on the Rafael R828D chip, which Rafael Micro no longer produces. We did have access to a large stockpile that we calculated could give us about a year of sales. As 2024 approached, we were very lucky that our contract manufacturing partner was able to secure a new large stockpile, which has brought us to where we are now.
Unfortunately, this stockpile has now been exhausted, and as far as we are aware, no other usable stockpiles exist, so no more Blog V4 productions will be possible. Initially, we had hoped to produce another two large batches, which would have brought us closer to the end of 2026; however, we have just confirmed that the last R828D chips that we could possibly obtain were all faulty in some way.
Going forward, the Blog V3 will remain in stable production.
We are also working on releasing a new Blog V4L 'lite' product, which will use the R828S chip. The difference is that the R828S has only two inputs, rather than the three found on the R828D, so the additional filtering used on the Blog V4 will not be possible. However, the same Blog V4 architecture with the HF upconverter will still be used. The lack of additional filtering also comes with a small upside trade-off, which is better sensitivity.
We expect to have a small initial batch of Blog V4L dongles available for sale in the next one to two months. Please be aware that the Blog V4L will require a driver update since as far as we are aware, the R828S has not been used in an RTL-SDR type product before. The Blog V4L will also be a limited edition product, as with the R828D, the R828S is not in production anymore, and so we will be relying on a stockpile.
We are also in the very early stages of scoping out a Blog V5 product, but note that this is unlikely to be ready this year.
Resellers may still have limited stock of the Blog V4. Please use our resellers' list on our store page, as there are many fake listings of the Blog V4 product on marketplace sites. Most of the fake Blog V4 listings use a copied Blog V4 enclosure but a Blog V3-clone circuit inside, or sometimes not even that.
I hope that everyone has enjoyed the RTL-SDR Blog V4 product while it has been out! Thank you to all customers who have supported the blog.
Over on YouTube, Gabe from the saveitforparts channel has uploaded a video where he tests out his Discovery Drive and Discovery Dish with L-Band feed for creating sky heatmaps of L-band satellites.
If you were unaware, Discovery Drive is our sister company KrakenRF's most recent successful crowdfunding campaign, which was successfully funded a couple of weeks ago. Discovery Drive is a portable antenna rotator with low power requirements, designed for use with Discovery Dish and other antennas of similar size and weight.
In the video, Gabe writes a custom script that has the Discovery Drive sweep the sky while simultaneously taking RF power readings with the Discovery Dish and L-band feed. The result is an image showing where L-band satellites are in the sky. He goes on to conduct experiments with the hydrogen line and sun imaging, as well as with satellites at UHF frequencies.
