Category: Applications

Cascade-SDR: A Web-Based Multimode Receiver App for RTL-SDR Dongles

Over on GitHub, developer Jens Engfors has released Cascade-SDR, a free and open source web-based receiver app designed specifically for RTL-SDR dongles. Cascade-SDR uses a Python backend that owns the dongle and handles all the DSP, paired with a browser frontend for the UI, waterfall, audio, and maps. The two communicate over a WebSocket, which means you can run the backend on a Raspberry Pi or mini PC and access it from any browser, phone, or tablet on your network.

Cascade-SDR has a live waterfall and spectrum scope view, with click-to-listen demodulation for WFM, NFM, AM, SSB, and CW, complete with RDS decoding, FM stereo, and a Morse decoder. CascadeSDR also includes a wideband Sweep mode, a channel Scanner, IQ recording and replay, and a built-in antenna helper that tells you how to set up the RTL-SDR.com dipole kit for your tuned frequency.

It also supports decoding of various digital modes, including ADS-B, AIS, APRS, ACARS, DAB+, NOAA APT weather satellite images, SSTV, POCSAG/FLEX pagers, and 315 to 915 MHz ISM band devices like weather stations and TPMS sensors. However, to decode most of these modes it is necessary to install various decoder software that it is dependent on such as dump1090, AIS-catcher, direwolf, welle-clide, multimon-ng, and rtl_433. 

Cascade-SDR runs on Windows, macOS, and Linux/Raspberry Pi. The readme includes instructions on installing the software on the various OS platforms.

AI-Disclaimer: This software has used Claude for development.

Cascade-SDR Screenshot
Cascade-SDR Screenshot

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.

HamDash SDR Web App Running an RTL-SDR
HamDash SDR Web App Running an RTL-SDR

NRSC5 Studio: A New Feature-Rich Windows GUI for the nrsc5 HD Radio Decoder

We've recently had several submissions about the release of a new program called NRSC5 Studio, a new native open source Windows and Linux supported GUI for the nrsc5 HD Radio decoder. We note that in the past, we've posted about nrsc5 and the NRSC5-DUI interface.

nrsc5 is an open source decoder for the proprietary HD Radio digital audio standard used by FM broadcasters in North America, and it works with low-cost RTL-SDR dongles. NRSC5 Studio is written in Rust with an egui-based dockable interface, and it wraps nrsc5 to provide tuning, HD1 to HD4 subchannel selection, station presets, and now-playing metadata with album art and station logos.

NRSC5 Studio appears to be quite feature-rich. There's a live FFT spectrum and waterfall display tapped from the same I/Q stream feeding the decoder, a QPSK constellation viewer driven by live MER readings per sideband, and a closed loop AGC that automatically tunes the R820T2 gain table to maximize MER. Other extras include a rolling 8-hour album art collage heat map, a 24-hour song log with CSV export, and TPEG traffic map and animated weather radar decoding on stations that broadcast it (currently iHeartMedia stations only).

A portable zip release is available on the GitHub releases page, requiring no installer or admin rights.

AI-Disclaimer: The software Readme credits GitHub Copilot, an AI tool.

NRSC5 Studio Screenshot
NRSC5 Studio Screenshot

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

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.

Receiving US Nuclear Detection Satellite Signals with RTL-SDR, Discovery Dish and Discovery Drive

Over on the Saveitforparts YouTube channel, Gabe has documented how he accidentally discovered signals coming from the GPS-satellite-based US nuclear detection system.

While scanning the GPS L3 frequency around 1381 MHz with his RTL-SDR, Discovery Dish, 1420 MHz Hydrogen line Discovery Dish feed, and Discovery Drive, Gabe caught short intermittent data bursts instead of the usual navigation signals. It turns out L3 is used by the GPS constellation for nuclear detonation detection, as the satellites double as arms-control sensors. When one detects a possible event, it relays the message across the network, the only time this frequency sees activity.

Later in the video, Gabe also swaps the dish feed to compare against a regular GPS L1 signal at 1575.42 MHz, and notes that radio astronomers are reverse-engineering L3 to filter it out, since it sits close to the protected 1420 MHz hydrogen line.

I Found The US Nuclear Detection System In Space

SkyLight Ceiling: Projecting Live ADS-B Aircraft Positions Onto your Ceiling

Recently, Cameron Paczek has created a new project called SkyLight, where art meets technical implementation by displaying a live view of aircraft flying overhead on your ceiling. SkyLight consists of a projector, Raspberry Pi 5, RTL-SDR dongle, and some custom software.

The Raspberry Pi 5 and RTL-SDR receive live ADS-B data from local aircraft, and the projector points up at the ceiling and displays the live locations of aircraft as they fly overhead, effectively giving you a simulated X-ray through your roof. The projections also include the sun, moon, bright stars and constellations, and live satellites. 

This project reminds us of a British Airways billboard in 2014 that used live ADS-B data to have a child on the screen point directly at incoming aircraft. We note that these SkyLight and billboard projects would not be possible without live ADS-B data, as ADS-B aggregation sites like ADSB-Exchange and Flightradar24 typically have a few-minute delay and require payment for their APIs.

Cameron aims to productize his idea into a ready-made kit and crowd-fund it in the near future. If you are interested, you can sign up for his notification mailing list over at skylightceiling.com.

AI Disclaimer: We note that this project appears to have been coded with the help of AI tools.

Skylight Ceiling Projecting Live Aircraft via ADS-B data on the Ceiling
Skylight Ceiling Projecting Live Aircraft via ADS-B data on the Ceiling

Dump1090 For Android Updated to V2

Thank you to Christian from ebcTech for writing in and sharing with us that their Dump1090 app for Android has recently been completely redesigned. We first posted about this app back in 2021. The developer notes that the V2 redesign is faster and has an improved UI.

The app allowes users to use an RTL-SDR dongle connected to an Android device to receive ADS-B signals from aircraft and plot their locations on a map. When selecting an aircraft, the app also shows the aircraft's live flight data and a picture of the aircraft.

Screenshots of the new UI
Screenshots of the new UI
RTL-SDR ADS-B Dump1090 Android

ITCMON: Interoperable Train Control Monitoring Software Released

Interoperable Train Control (ITC) is a radio protocol operating at 220 MHz that is used by most railroads in the United States. ITC is a safety system designed to help prevent train-to-train collisions, derailments caused by excessive speed, incursions into work zones where maintenance crews are present, and movement of a train through a switch left in the wrong position. It runs in the background as a safety mechanism to apply the brakes if the crew makes a mistake.

Recently, Katso Juna wrote in to us to let us know that they have created a new program for Windows called "ITCMON:  Interoperable Train Control Monitoring software". Katso writes:

I will first address the obvious concerns: ITC/PTC is much safer than ATCS ever was. Due to the HMAC (Hashed Message Authentication Code) attached to every important message, it is not possible for anyone to spoof data without knowing a secret key.

Anyways, this first release runs on Windows (tested on Win 11) and needs an RTL-SDR, a 220mhz antenna, and the regular Windows Zadig RTL/USB drivers installed.

To make the most use of the software, you'll have to figure out the signal vs switch bits for each Wayside (not too hard), and also figure out where those Waysides are located to give them names. If its found to be useful then a next step might be to feed this data to a dispatcher type display. There is a lot of other interesting data that could be used.

So it seems that while the data messaging is encrypted, once you've matched the signal/switch bits for each wayside, you can still infer local train movements and activity from the wayside status beacons.

Katso has also mentioned that there is a groups.io page called PTCTalk where the program is being discussed.

ITCMON Screenshot
ITCMON Screenshot