Thank you to ReLLL for writing in with an update on his decoder plugins, which we previously posted about as the “Advanced FT8/FT4 DX Decoder” just yesterday.
Kondor Weak Signal Modes Decoder is the renamed and expanded version of the original plugin. It now decodes WSPR, FST4, FST4W, JS8, and Q65 in addition to FT8 and FT4. Its features include: A day/night DX map with SNR colors, station and country statistics, a DX activity bearing display, searchable tables, SQLite and CSV logging and optional forwarding to GridTracker.
ReLLL also added a new plugin called Maverick Text Modes Decoder (formerly CW Notebook) which decodes CW, RTTY, JS8, Olivia, PSK31 and PSK63. It provides a CW transcript with Markdown logs, simultaneous frequency tabs, spectrum discovery, pinned priority signals, and RX SNR readouts.
Both plugins now support standard SDR++ 1.2.0 and SDR++Brown 1.2.1 on Apple Silicon Macs running macOS 15 or later. There is also now a downloadable Windows preview for SDR#.
ReLLL welcomes reception reports, bug reports and UI ideas via GitHub Issues or X @FoxOnTheRunTr.
Thank you to ReLLL for writing in and sharing news about the release of his "Advanced FT8/FT4 DX Decoder", a free and open-source plugin for SDR++Brown running on Apple Silicon Macs. SDR++Brown is a popular unofficial fork of SDR++ that already includes some built-in FT8 decoding capabilities. This plugin builds on that and adds a full DX monitoring workspace directly inside the SDR software, so there is no need to pipe audio out to WSJT-X just to see who you’re hearing.
The plugin decodes FT8 and FT4 and plots received stations on a DX map. It also displays tables of unique stations, all decoded messages and countries heard, along with receiver SNR and approximate distances calculated from grid locators. Other features include table filtering and sorting, persistent CSV reception logging, optional waterfall notifications, and a WSJT-X format UDP output that can feed GridTracker directly. Decoding also continues in the background even when the plugin window is closed.
We note that the latest release also adds decoding for WSPR, FST4, FST4W and Q65. Note that the plugin is not intended for use with standard SDR++, or on Windows or Linux. Installation instructions are on the GitHub page, and a user guide is also available.
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
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
AI Disclaimer: This software is likely to be AI-assisted or vibe-coded.
Thank you to Julian for writing in and sharing with us his interesting project called SDR-- (SDR minus minus). SDR-- is an open-source app that lets you wire devices, decoders, and displays together on a desktop window or browser-based canvas. It is described as "a software-defined radio application with a visual signal path. Connect devices, decoders, displays, and recorders on a canvas, then pin the controls you use to a rack."
A separate Rust server, which can sit on the same PC or a remote computer (like a Raspberry Pi), handles the DSP. Julian notes that SDR-- has native RTL-SDR support, and decoders for ADS-B, AIS, POCSAG, FT8, SSTV, and RDS are already implemented, with more in progress. The app also has a built-in signal generator and a repository of IQ recordings that can be used for experimentation and testing the various decoders.
The project releases are available on GitHub releases, and they cover Windows, Linux, and MacOS.
SDR++ is a popular general-purpose SDR receiver program, commonly used by RTL-SDR enthusiasts. It works on all platforms, including Android; however, the original author has not expressed interest in officially publishing it on the Google Play Store, so sideloading the APK has been the only way to get it on Android.
Recently, we've learned of an unofficial SDR++ fork called "SDR++ iak" that is now on the Google Play Store. The iak fork by OK1IAK includes several improvements, notably a touch-friendly UI overhaul, various crash fixes, KiwiSDR world-map directory, radiosonde decoder, and support for the QRP Labs QMX transceiver.
Thank you to Marco Argilli (IU4HMY) for writing in and sharing with us the release of a new SDR# Panadapter plugin that turns the popular RTL-SDR- and Airspy-compatible program SDR# into a panadapter for your transceiver. A panadapter gives you a live spectrum and waterfall view of the band around your radio's tuned frequency, which makes it much easier to spot activity, find clear frequencies, and visually navigate a busy band. Synchronization between the radio and SDR# is handled by OmniRig, so as you tune your transceiver, the panadapter display follows along.
To use the plugin, you connect your SDR to your transceiver's IF or antenna output, then set the receiver IF frequency and a per-mode offset in the plugin settings, with changes saved to a JSON config file. The plugin also has band presets, where a right-click on a preset button stores a snapshot of frequency, demodulation mode, and zoom level, so you can recall a favorite spot instantly. SDR# version 1921 or newer and the .NET 9 framework are required, and it runs on Windows 8, 10, and 11.
There are a couple of limitations worth noting. Marco recommends using Center Frequency mode for the best performance, and because OmniRig exposes the frequency as a 32 bit COM value, frequencies above around 2.1 GHz are not supported. The plugin does not appear to be open-source, but it is free for personal and non-commercial use.
Thank you to Jayoung from HTWAVE for submitting news about the upcoming crowdfunding campaign for their "Integrive-100" software-defined radio. The Integrive-100 is an AD9361 based SDR with 70 MHz – 6 GHz tuning range, 2x2 MIMO TX/RX channels and up to 56 MHz bandwidth per channel.
They note a defining feature is a pre-built and validated FPGA-based PHY baseline with API access, allowing researchers to skip the basic infrastructure development steps and move straight to developing onboard DSP algorithms on the AMD Zynq-7020 FPGA/ARM CPU.
They write:
SDRs have long served as flexible testbeds for wireless communication research. Their ability to define functions through software makes them ideal for rapid prototyping. However, many SDRs struggle with non-deterministic latency caused by relying on a host PC for real-time signal processing where samples must traverse a communication interface and be handled by a non-real-time OS. This makes it difficult to accurately measure real-time performance, a fundamental requirement for 5G/6G research. This challenge is exactly why we decided to build our own SDR from the ground up.
By leveraging FPGA acceleration, we offloaded real-time signal processing entirely to the board, eliminating host PC dependency. While PC connectivity remains an option for monitoring and logging, the critical signal processing is handled on-board, ensuring that jitter is minimized and allowing you to test your algorithms in the most precise environment possible. Furthermore, by integrating an ARM processor and Embedded Linux, we’ve enabled high-level resource management and seamless compatibility with existing SDR software stacks.
In MIMO environments or scenarios involving high mobility, phase noise and phase synchronization are significant hurdles. Since our goal was industrial-grade deployment, we focused intensely on phase coherence. Unlike low-quality oscillators that degrade RF signal quality, we utilized high-performance components to achieve ultra-low phase noise and synchronized dual oscillators to ensure inter-channel phase consistency.
The best indicator of this stability is our OFDM 256-QAM constellation, which demonstrates the superior phase stability and synchronization our platform can achieve. Furthermore, our real-time video streaming demo, successfully transmitting high-throughput data with zero errors, stands as a testament to the integrity of our synchronization and phase noise control.
Finally, we provide robust API access (C, C++, Python), allowing users to control the system through simple function calls without needing deep FPGA expertise. By supporting standard software frameworks, researchers can easily port their existing projects to our hardware. Our goal is to eliminate the days or weeks spent on infrastructure setup. We want you to achieve productivity from Day 1.
Thank you to Argilli Marco (IU4HMY) for writing in and sharing with us his Python application called "SDR# Frequency Manager 1.0.1" for managing frequency lists in SDR#. SDR# is a popular free SDR program commonly used with RTL-SDR and Airspy dongles. Argilli writes:
SDR# Frequency Manager is a Python application designed to simplify the management and editing of frequency lists used by SDR#. The software allows you to open, edit, and save SDR# XML frequency files in a clear and structured interface.
The application is free but closed source and available on his website.
