Category: Amateur Radio

September 8, 2026

Cat2Web: Sync a Transceiver with WebSDR/KiwiSDR

Thank you to Val (LZ2XA) for writing in and sharing with us a program he's created called "Cat2Web," which is designed to keep a ham transceiver and a public browser SDR, such as a KiwiSDR tuned to the same frequency and mode, in both directions. This is useful for amateur radio operators, as they could easily determine if their signal is being heard by a distant public remote SDR station.

Cat2Web (C2W) is a small Windows app that keeps a ham transceiver and a public browser SDR — WebSDR, KiwiSDR, OpenWebRX/OWRX+ — tuned to the same frequency and mode, in both directions.

Besides standard CAT (via OmniRig), it controls FlexRadio 6000/8000 directly over the network (SmartSDR TCP, no CAT cable) and SunSDR via TCI, and it can pull a SpyServer/Airspy stream and demodulate it itself. It also lets you pick the audio
output device for the SDR sound, and stores a frequency offset per bookmark.

We note that the program is not open source and has a €20 lifetime license price tag attached to it. However, a demo is available with full sync, but limited bookmarks.

September 3, 2026

FreeDV RADE: An Open-Source Digital Voice Mode for HF that Beats SSB at Low SNR

Thank you to Rebecca Key (KO4KVG) for writing in and sharing with us an article she's written over on the ARDC website about a relatively new amateur open-source radio digital voice mode called FreeDV RADE.

ARDC is a private foundation that issues grants that support amateur radio and digital communications technologies. FreeDV is an ARDC grantee, and it has been using the funds to develop "a digital voice mode that could compete with SSB across varying signal-to-noise conditions on HF while providing more natural-sounding speech".

Last year, they released the FreeDV Radio Autoencoder (FreeDV RADE), which is their flagship digital voice mode. FreeDV RADE incorporates both machine learning and classical DSP, resulting in working audio at SNRs as low as -2 dB, with only half the bandwidth of a typical 3 kHz SSB voice signal. The article goes on to describe how the audio quality, power, and bandwidth efficiency are superior to other digital voice modes.

The article also mentions how FreeDV RADE is seeing increased adoption by hardware manufacturers, with FlexRadio now supporting the mode in several radios. It also mentions upcoming improvements, including a goal of reducing bandwidth use to under 1 kHz.

August 7, 2026

9GRadio: An Android RTL-SDR App for Spectrum Monitoring and Decoding Analog/HAM/Aviation/Marine Radio Traffic

Thank you to Richard (9G5AR) for writing in and sharing with us the release of his open source Android app called 9GRadio. Richard writes that 9GRadio is an app designed for spectrum monitoring/analysis and the decoding of analog/ham/aviation and marine radio traffic.

In terms of demodulation it supports AM, FM, NFM, WFM, WFM Stereo, USB, LSB, CW, CWR, DSB and RAW IQ modes.

For digital decoding, it supports APRS, digital voice modes such as DMR, D-STAR, YSF, dPMR, NXDN, and aircraft, marine, and datalink modes such as ADS-B, AIS, ACARS, RDS, and multilateration.

Richard also notes that 9GRadio includes a full multilateration stack for locating transmitters, which works with 2+ networked 9GRadio receivers. Interestingly, the multilateration stack is noted to be protocol-agnostic, meaning it should work not only with ADS-B, but also with any mode that provides a digital identity for a transmission, such as AIS, ACARS, RDS, and digital voice modes.

The app is not available on the Google Play Store, but the APK is available for sideloading on the project's GitHub Releases page, along with the open source code.

July 28, 2026

SDROxide: A New SDR Client for HAMs and SWLs written in Rust

Thank you to Josef (OE3JJS) for writing in and sharing with us the release of his new open-source software called SDROxide, an SDR client designed for HAMs and SWLs (short-wave listeners), written in Rust. The software supports Linux, Windows, macOS, and also has a web client. As it supports SoapySDR, RTL-SDR dongles are supported for RX. Josef writes about SDROxide:

It's a completely new project written in Rust, supporting many SDR interfaces (CAT/Audio, CAT/IQ, SoapySDR, HPSDR, TCI) and with loads of features built in that used to require extra programs: FT8/FT4, SSTV, RTTY, PSK, OLIVIA, THOR, FSQ, a CW/RTTY/PSK skimmer, there's dx cluster and sota/pota spotting, a logbook with integrations for QRZ.com, HamQTH, eQSL, LoTW, there's neural-network noise reduction, a 3D "hamclock" that visualizes QSOs, satellites, Aurora, CME cones, with up-to-date images of the sun's surface, and you can run the client locally, remote with native binary, or remote via the web (WASM).

Josef notes that the project is fully open-source and available on GitHub.

AI-Disclaimer: The author notes the use of local and hosted LLMs in the development of this software.

July 6, 2026

Testing WSPR HF Propagation with a Raspberry Pi 3B+ and TAPR Shield Running WsprryPi

Thank you to Simone Spadino (SWL ID I8926BA), who wrote in to share his low-cost WSPR setup. WSPR (Weak Signal Propagation Reporter) is an amateur radio mode designed to test propagation paths using very low-power transmissions, with receiving stations reporting spots in real time to the WSPRnet map.

Simone's setup consists of a Raspberry Pi 3B+, which can be made to modulate a square wave RF signal on one of its GPIO pins via the WsprryPi software. Because a square wave generates many harmonics, he used the 20m WSPR shield from TAPR, which provides a low-pass filter to remove them. A dipole made from simple electrical monopole wire was connected to the shield via 50 ohm coax, and the signal was transmitted at 14.0971 MHz.

Transmitting from his rooftop in the center of Bari in southern Italy, Simone had his beacon received in England, Finland, Cyprus, and the Canary Islands, all more than 3100 km away. He repeated the experiment a week later with similar results. This is a reminder of how far low-cost hardware can transmit with a resilient protocol like WSPR.

June 18, 2026

HamDash: A Free Real-Time Ham Radio Dashboard with a Browser-Based RTL-SDR Receiver

Thank you to several readers who have pointed us to HamDash. HamDash is a new free real-time ham radio dashboard that aims to be the always-on monitor for your radio shack. Built by Peter (G0LIW), the web-based app combines HF propagation, space weather, DX cluster spots, POTA and SOTA activations, a contest calendar, and a greyline map into a single customizable view. There's no account or subscription, and it runs in any browser, making it a good fit for a dedicated second monitor, a tablet, or a Raspberry Pi sitting in the shack. We note that despite being free, the project doesn't appear to be open source, as we could not find any public source code repo.

The dashboard includes live solar flux, K-index, X-ray flare, and aurora data so you can tell when the bands are open, plus VOACAP-based propagation predictions and Met Office/MeteoAlarm weather alerts useful for portable operating. A Visual Layout Builder lets you arrange modules into rows and slots exactly how you want, and a touchscreen-friendly on-screen keyboard makes it usable on a mouse-only or kiosk-style setup.

Of interest to RTL-SDR users, HamDash includes a browser-based SDR receiver called SDRCOM that works with an RTL-SDR V3 or V4 dongle over WebUSB, so you can run it in Chrome or another Chromium browser like Edge or Opera directly. The free SDRCOM Lite edition is included with HamDash and covers AM/FM/SSB/CW tuning, a waterfall display, an FT8 decoder, a basic 3-band EQ, and a 100-slot memory bank. There's also a paid SDRCOM Pro edition for a one-year license with no auto-renewal $9.99 fee that adds enhanced waterfalls, FT8 and FT4 decoders, an ADS-B engine with 3D aircraft tracking, 4-band noise-reduction DSP, an auto-lock band scanner, a WAV recorder with scheduler, and a 1000-slot memory bank.

AI-Disclaimer: While not advertised as AI-coded, the author's company, Nemeta AI Software Services LLC, and the UI-style hints at AI development tools having being used.

June 11, 2026

AirPulse Desktop: Turn an RTL-SDR into an Amateur Radio Repeater Activity Reporting Station

Thank you to the team at Feedline Labs for writing in and sharing news of their new project called AirPulse Desktop. AirPulse is a Windows desktop application that turns an RTL-SDR into a small repeater activity monitoring station.

The software continuously scans the output frequencies of nearby amateur radio repeaters, detects when a signal exceeds an activity threshold, and reports those hits to Feedline Labs' live "Greyline Fabric" system. The idea is to build a real-time map of which repeaters are actually in use, rather than relying on static directories that are often outdated or filled with abandoned systems.

For the launch, Feedline Labs is granting free lifetime AirPulse Desktop licenses to the first 75 users who get set up and begin contributing activity reports. The installer is not being posted publicly for now, so interested RTL-SDR owners will need to request access through feedlinelabs.com. A short video demonstrating the concept, the desktop app, and the scanning and reporting process is available below:

Own an SDR? Help Build the Greyline Live RF Intelligence Fabric | AirPulse Desktop Beta

Watch this video on YouTube

AI Disclaimer: We note that this project appears to make heavy use of AI-generated images. We do not know if AI-generated code is used as the code appears to be closed source.

May 19, 2026

GopherTrunk: A New Pure-Go Trunked Radio Scanner Supporting P25, DMR, TETRA, NXDN and More

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.

Gopher Trunk: A New Digital Trunking Scanner for RTL-SDR written in Pure-Go — GopherTrunk: A New Digital Trunking Scanner for RTL-SDR written in Pure-Go

AI Disclaimer: This program credits Claude as a contributor.