Category: SDRplay

An Unofficial Bilingual English and Chinese User Guide for SDRplay’s SDRconnect Software

Thank you to BG7BAG for writing in and sharing a free user guide for SDRconnect, SDRplay's multi-platform software for their RSP series of SDRs, which we've covered several times before. SDRplay only provides a "Quick Start" guide and a few application notes for SDRconnect, so BG7BAG wrote a full manual from scratch, based on daily use with an RSPdx-R2.

The guide is written side by side in English and Chinese, with a shared glossary of SDRconnect's interface terms, so it may be most useful to Chinese-speaking SDRplay users, for whom there is no official manual. It is based on SDRconnect V1.0.10 and includes a quick start section, a 22-chapter manual covering topics like remote operation, troubleshooting and PPM calibration, and an advanced guide on HDR mode, notch filtering, IQ recording and scheduling. 

BG7BAG also shared his HAM Radio Atlas, a free map of over 12,000 amateur radio repeaters on the 2m, 1.25m and 70cm bands, searchable by location, callsign and band. Repeater data currently covers the USA (26 states), Australia, China, Austria and New Zealand, with a province-by-province list for mainland China.

A screenshot of one part of the manual.
A screenshot of one part of the manual.

AI Disclaimer: We note that this guide appears to have been written with the help of AI.

sdrtop Update: Wi-Fi Airtime Tools, POCSAG Pager Decoder and Native Airspy R2 Support

Earlier this month we posted about sdrtop, a Rust-based SDR bench instrument that runs in a terminal and is aimed at measurement rather than listening. Viktor László (MusiThang on GitHub) has now written in again to share several updates. Viktor notes that the goal is still to "make radio signals and the measurements behind them inspectable, rather than hiding everything behind a decoded result."

The biggest additions are new Wi-Fi tools. sdrtop can now survey 2.4 GHz channels 1 to 13 and name the least busy one, inspect a single channel frame by frame at three time scales, and show a channel's airtime use second by second. These tools need 20 Msps, so you need an SDR like the HackRF. There is also a new POCSAG pager decoder written from the ITU standard without external libraries. Viktor tested it over the air by transmitting with a HackRF and PortaPack Mayhem and receiving with an Airspy R2.

The Airspy R2 is now natively supported too. Its gain staging follows the R2's Linearity and Sensitivity gain curves, and sdrtop warns you before the tuner clips. RTL-SDRs are still fully supported, and native support for the SDRplay RSP1B and Airspy HF+ Discovery is in progress. The code is open source under the GPLv3 and available on GitHub.

Some screens from sdrtop
Some screens from sdrtop

AI Disclaimer: The project's CREDITS.md file notes that Claude Code was used for implementation, architecture discussion and problem-solving.

DAB SDR GUI: An Open-Source DAB+ Receiver for the RTL-SDR and SDRplay

Thank you to Tomas Krajco for writing in and sharing DAB SDR GUI, a Windows program for listening to DAB+ digital radio with an RTL-SDR or SDRplay RSP. DAB+ is the digital broadcast radio standard used in much of Europe and Australia, and is transmitted in VHF Band III (174 - 240 MHz).

The program scans Band III and saves the stations it finds, then plays the selected station while showing its logo, ensemble name, and song text. It also has a 10-band equalizer with presets and a spectrum analyzer with RTA bar, FFT curve and LED bar display modes. Note that the analyzer shows the decoded audio rather than the RF spectrum, so this is a program for listening rather than signal analysis.

Decoding is handled by Tomas' own plain C DAB/DAB+ library called dab-lib, and both the library and the GUI are open source under the GPLv2 license. The latest Windows installer is v0.1.5, and older Android (RTL-SDR) and Linux AppImage (SDRplay)
builds are also available on the SourceForge files page.

DAB SDR GUI Playing a DAB+ Station
DAB SDR GUI Playing a DAB+ Station

AI Disclaimer: Recent commits to the dab-lib GitHub repo, including the port of the GUI to WinUI 3, list GitHub Copilot as a co-author.

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.

NyxScope: A Windows Multi-Protocol SDR Decoder Program with Multiple Digital Native Decoders

WARNING: Multiple people have noted that this program is not working as expected and may be overly buggy.

Recently, we've learned about NyxScope, a multi-protocol SDR receiver program for Windows that comes with multiple native decoders built right into the software. Their own description describes this all-in-one program best:

You get spectrum and waterfall, multiple concurrent VFOs, trunked-radio following, digital voice, aviation and marine tracking, paging, ISM sensors, HD Radio, and transcription, in one binary.

NyxScope includes decoders for P25 Phase 1 and Phase 2 voice, EDACS and NXDN control channels, ADS-B, AIS, ACARS, POCSAG, FLEX, LoRa CSS PHY + LoRaWAN MAC, Morse, RDS, CTCSS/DCS, Iridium decoding (with voice), and also includes a signal classification tool, Bluetooth LE scanner, and Whisper voice-to-text transcriber. It also outsources decoding of other protocols to mature decoding software such as multimon-ng, rtl_433, dsd-neo, nrsc5, direwolf, dumpvdl2, dump978, rs41mod where required, noting that the outsourced decoders are bundled with the software, meaning no extra installation work is required.

The software supports RTL-SDR, HackRF, Airpsy, bladeRF, SDRplay, Fobos and PlutoSDR. It also supports using multiple SDRs used in parallel.

The software does not appear to be open source, but it is provided for free with a limitation of 3 concurrent VFOs and a limitation on recording, transcribing, and pager messages. A perpetual per-machine license for $89.95 can be purchased to lift these restrictions and add access to their FCC frequency lookup database.

AI-Disclaimer: While the developers have not noted any use of AI tools, we suspect that AI was used in the creation of this software.

NyxScope Screenshot Scanning the 800 MHz Band
NyxScope Screenshot Scanning the 800 MHz Band

iq_tool: A Command Line Tool for Resampling, Filtering, Shifting and Correcting IQ Data Streams

Thank you to Eric Inloes for submitting to the blog his new tool called "iq_tool". This is a tool designed to "provide an easy, fast, and lightweight command-line utility for converting I/Q data from files or SDRs to a specific sample rate and format, and then either piping it to other programs or writing it to a file". Or in other words have a "neutral ffmpeg like converter tool but for IQ data".

Many SDR software tools are written for specific SDR hardware, such as RTL-SDRs, and may only accept a specific sample rate, type, or bit depth, meaning other SDRs cannot use these tools. The goal of iq_tool is to easily allow the IQ data stream from any SDR to be converted into a compatible format. 

Eric gives some examples. For example, if you wanted to use rtl_433 with an Airspy you could run the command:

iq_tool --input airspy  --airspy-gain-mode linearity --airspy-gain-value 15 --output stdout  --sdr-rf-freq 433.92e6 --output-sample-rate 250e3 --output-sample-format cu8 --output-agc | rtl_433 -r -

Similarly, for an SDRplay, you could run:

iq_tool --input sdrplay   --sdrplay-lna-state 15 --sdrplay-antenna b --sdrplay-if-gain -50 --output stdout  --sdr-rf-freq 433.92e6 --output-sample-rate 250e3 --output-sample-format cu8 --output-agc | rtl_433 -r -

We note that Eric released this tool with the caveat that it is experimental and was written with heavy AI assistance.

iq_tool example converting from a networked Airspy and piping into rtl_433
iq_tool example converting from a networked Airspy and piping into rtl_433

Web-Spectrum: Web-Based Spectrum Analyzer and GPS Signal Analyzer with RTL-SDR Support

Over on GitHub we've recently seen a new open source program release called "web-spectrum". Web-spectrum is a multi-purpose browser-based tool. One interesting feature is that it allows you to view the GNSS spectrum (via a connected RTL-SDR or SDRplay with an appropriate antenna), decode it to a position, and also analyze the signal for jamming. It uses gnss-sdr or Gypsum as the backend GNSS processing tool.

The tool can also be used as a real-time spectrum analyzer, and for this, it supports RTL-SDR and SDRplay as well as the tinySDR Ultra spectrum analyzer.

Finally, in addition to GPS decoding, it also supports ADS-B and ISM band decoding.

Web-Spectrum: A Browser based tool for spectrum analyzer, GNSS analysis, and ADS-B and ISM band decoding.

Guglielmo FM and DAB Receiver Software Updated to Version 0.7

Thank you to Marco for letting us know that his Guglielmo software has recently been updated to Version 0.7.

Guglielmo is an FM and DAB receiver for Linux, Windows and MacOS. It supports all major SDRs, including RTL-SDR, Airspy, SDRplay, HackRF, and LimeSDR. It is designed to be easy to use for media users rather than hobbyist technical users.

Version 0.7 adds the following features:

  • Raspberry PI appimage
  • UI improvements
  • Basic skins support
  • Logo handling

The new Raspberry Pi appimage, and binaries for other platforms can be found on the GitHub Releases page. Just expand the "assets" tab.

Guglielmo: Screenshot of the DAB Interface