Category: Mobile

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.

9GRadio GIF of various screens
9GRadio GIF of various screens

Radio Silence: A Native iOS App for Listening to Public KiwiSDRs

Thank you to 'Radio Silence Dev' for writing in and sharing the beta release of his iOS native app, Radio Silence, designed for listening to public KiwiSDR receivers around the world on an iPhone or iPad.

The app streams live audio from the KiwiSDR network, with a live directory showing each node's signal quality, load, and online status. If a receiver drops out mid-session, the app will automatically fail over to another one. There is also a tap-to-tune live spectrum waterfall.

Radio Silence also includes CW, RTTY and FT8 decoders, which all run on-device rather than on the receiver, printing text under the dial as it comes in. Audio keeps playing with the screen locked, and captures are saved to a logbook tagged with frequency, mode, node, S-meter reading and UTC timestamp, with export to ADIF, CSV and WAV. Captures can also be shared as QSL-style reception report cards stamped with the solar flux and Kp index at the time of the catch. NAVTEX and SSTV decoders are in development.

The developer notes that the app is written to be a good citizen on the KiwiSDR network, releasing its channel slot when listening stops and handing it back automatically if playback is left running unattended. Streaming uses about 22 MB per hour.

Radio Silence is free during the beta, and listening is set to remain free at launch, with any future subscription covering software features only. Beta invites can be requested via radiosilencesdr.com.

Radio Silence: Waterfall View
Radio Silence: Waterfall View
Radio Silence: Decoding FT8
Radio Silence: Decoding FT8

CellScope: LTE Sniffing on Windows

Over on YouTube, Sarah from the SignalsEverywhere YouTube channel has uploaded a new video showing a new open-source program she's developed called CellScope, which is used for LTE sniffing. She notes that CellScope is essentially LTE Sniffer, but ported for Windows. CellScope needs a wideband SDR, and it currently supports LibreSDR B210 Clone, HackRF and the Airspy R2/Mini

LTE (aka 4G) is a modern mobile wireless standard used by cellphones for data. While it is encrypted, there is still some data transmitted in the clear, such as the devices connected to the cell site and how much data they are pulling down, if there is an active call on the cell site, and of course the data activity can be useful to monitor too. 

In the video Sarah shows CellScope in action, demonstrating it detecting a call from her phone and visualizing the data transfer activity from her device when pulling down data.

CellScope is open-source and available on GitHub. If you don't want to compile it yourself, the Windows executable can be purchased from her site for a minimum $0.00 donation.

CellScope: LTE Sniffing on Windows

VibeSDR Now Available on the Apple App Store + Running on an Apple Watch

Back in June, we posted about VibeSDR, an AI vibecoded free and open-source mobile SDR client for rtl_tcp and UberSDR/KiwiSDR/OpenWebRX servers developed for iOS and Android. Recently, Stuart Carr (Stuey3D) wrote in again to let us know that VibeSDR is now available on the Apple App Store for £2.99 and is soon to be available on the Android Play Store too.

In terms of updates, Stuart also notes that he's now developed VibeServer, which provides a more network-efficient way to share RTL-SDRs remotely via an Android phone. VibeServer compresses the data and transfers it at 120KB/s instead of the full 4.8MB/s required by rtl_tcp. 

Stuart has also developed an Apple Watch Buddy app version of VibeSDR which runs directly on an Apple Watch, allowing you to view and listen to the spectrum on your wrist. The watch version is still in beta, but Stuart notes that you can join the free beta on TestFlight.

As before, the latest open source code can be found on the VibeSDR GitHub https://github.com/stuey3d/vibesdr.

Finally, Stuart has provided us with 20 free promo codes to give away for the Apple App Store version of VibeSDR. To win a promo code, simply comment on this post (making sure to enter an email in the email field), reply to the X post, or comment on the Facebook Post (note that for Facebook you must montior your comment for a reply as Facebook does not allow private messages). 

Update: All promo codes have now been allocated, thanks!

AI-Disclaimer: This software was vibecoded with Claude.

VibeSDR Running on an Apple Watch
VibeSDR Running on an Apple Watch
Introducing VibeSDR Jr: A full SDR Client on your wrist.

Demod: An iOS/iPadOS Client for rtl_tcp, SpyServer and KiwiSDR

Thank you to Alphonse Romero for submitting news about the release of his new iOS and iPadOS SDR receiver app called Demod. Demod is a network client that connects to remote SDR servers, so it can be tried out immediately with no dongle needed at all. 

The app works as a client for rtl_tcp, SpyServer (Airspy and RTL-SDR), and KiwiSDR, all in a single app. It features a Metal-accelerated waterfall and spectrum display, AM/NFM/WFM/USB/LSB/CW demodulation, and adjustable bandwidth, gain, and squelch. Other features include frequency memories with CSV import and export, AirPlay and Lock Screen controls, and native layouts for both iPhone and iPad. It can also browse and connect to public SpyServers directly from within the app, which is how it can be used with no hardware of your own. The developer notes that it collects no data, with no ads or tracking.

Alphose writes that Demod is a solo project and is available on the US App Store for US$9.99. More information and screenshots can be found on the project website, and the app itself is available on the App Store.

The developer has also provided us with 15 free codes that we will be giving away in one week. To enter the giveaway, simply comment on this post (make sure to include your email address in the comment so that we can send you the code), the X post, or the Facebook post. (UPDATE: ALL CODES HAVE BEEN ALLOCATED NOW, THANKS!)

Demod iOS SDR App
Demod iOS SDR App

SwR Shortwave Radio: A New Android App for Listening to Public Online Shortwave Receivers

Thank you to RTL-SDR.COM reader Ladislav for submitting information about the release of a new Android app by Alexsxxx called "SwR - Shortwave Radio". This is an Android-only app that lets users easily listen to KiwiSDR and Web-888 receivers. The app appears to be free, with no in-app purchases.

SwR is a client for the worldwide network of public shortwave receivers. Tune in to live shortwave radio from hundreds of volunteer-run receivers around the globe — right from your phone.

Features:
• Connect to any public receiver
• Live spectrum and scrolling waterfall display
• Drag the spectrum to tune; drag the waterfall to pan the band
• Nixie-tube style frequency display with per-digit tuning
• AM, LSB, USB, CW and FM demodulation
• Zoom from the full band down to a narrow window
• World map of receivers — tap one to start listening
• Volume and mute controls

SwR - Shortwave Receiver App
SwR - Shortwave Receiver App

VibeSDR: A Mobile-First iOS and Android Receiver App for Remote SDR Servers and RTL-SDRs

Thank you to Stuart Carr (Stuey3D) for submitting news about his new software release, VibeSDR, a free and open-source mobile SDR client he has developed for iOS and Android. VibeSDR is designed to be touch-first rather than a desktop interface shrunk down to phone size. It is a fully native client for UberSDR, OpenWebRX/OpenWebRX+, and KiwiSDR with its own GPU-rendered waterfall and spectrum. It also supports local RTL-SDR dongles via RTL-TCP on both platforms and over USB on Android with no extra driver install required.

VibeSDR comes with a long list of features. The app has on-device decoders for RTTY, WEFAX, NAVTEX, SSTV, Morse, and FT8/FT4, plus access to server-supplied decoders, Leaflet-based HFDL and digital spot maps, FM stereo with RDS, a local bookmarks engine with daily EiBi schedule downloads, and full background audio. It also has band-aware blind tuning, where using lockscreen, headphone, or in-car media controls to tune across a band boundary automatically switches to the correct demodulator and step rate for that band and ITU region. The app also has Android Auto support with browsable bookmark and band plan lists and steering wheel tuning, and on iOS, it offers Siri voice commands to work around the current lack of full CarPlay approval.

Stuart is upfront and mentions that VibeSDR was AI vibecoded with Claude, hence the "vibe" part of the name. He notes that while he did not write code himself, he designed, extensively tested, and reported bugs over weeks of late nights. The app is not available on any app store at the moment, but he notes that the app will always be free and open source, with full source, APKs and IPAs available on the VibeSDR GitHub Releases page. He also plans to eventually list it on the App Store and Play Store for a fee of around £3 to cover store and development costs.

AI-Disclaimer: This software was vibecoded with Claude.

VibeSDR Screenshots
VibeSDR Screenshots

QuadRF: 4-Element Beamforming SDR Tile Coming to Crowd Supply

Back in January, we posted about open.space and their mission to unlock affordable open source earth-moon-earth (EME) bounce communications for the amateur radio public. Recently, we've seen that the project has been renamed to ScaleRF, with the EME system renamed to MoonRF, and the invisual tile renamed to QuadRF. They've also put out a new update post with a lot of interesting information and demonstrations. In the latest update, they also announced that the QuadRF 4-element tile will soon come to Crowd Supply for crowdfunding.

MoonRF is a software-defined radio-based tiling system that enables users to easily create large phased arrays by combining multiple smaller 'QuadRF' tiles consisting of four tile elements, a custom SDR, and a built-in Raspberry Pi 5. Although the ultimate goal is to produce a large system capable of working EME bounce communications, they show that a single QuadRF tile has considerable utility on its own.

An interesting application they show is the ability to visualize and track RF signals using a single QuadRF and their augmented-reality smartphone app. QuadRF appears to be limited to the C-band (4.9–6.0 GHz), but many modern devices, such as smartphones and drones, operate at these frequencies, and in the video, they are able to track these devices with perfect accuracy.

They also show that QuadRF has built-in web browser access to various programs, including a wireless camera decoder for drones.

Quad RF: A Closer Look