Category: Mobile

Echo Pro: KiwiSDR, OpenWebRX, WebSDR and FM-DX iOS Browser App now with Live Transcription and Translation

Back in April we posted about the release of Echo, a free iOS app designed for browsing global web-based KiwiSDR, OpenWebRX, WebSDR, and FM-DX software-defined radios. Mark, the developer of Echo, has written in to us again and wanted to share news about the release of the Pro (paid) version of Echo.

Echo Pro adds several features such as recording, on-device transcription and translation, iCloud sync, and the ability to access recordings across Apple devices. The transcription and translation service may be quite interesting, as it allows you to record an entire foreign radio program to text, and translate it to your language for later reading.

Echo Pro costs either US$4.99/month or US$39.99/year. More information about the app is available at echosdr.com.

Promo images from Echo
Promo images from Echo

RTL-SDR Pager: Android App for Receiving and Decoding POCSAG and FLEX Pager Messages

Thank you to Christian from ebcTech.eu for writing in and sharing with us the release of his new Android app called "RTL-SDR Pager" (Google Play Store link). The app is designed to work with an RTL-SDR dongle connected to the Android device. It is capable of decoding POCSAG and FLEX messages. However, Christian notes that he hasn't been able to test FLEX decoding so far because there are no FLEX channels in his area, so he would be interested in any feedback on this.

The app also provides push alerts, allowing you to monitor for a specific RIC or keyword and allows you to save channel lists.

The app offers a free demo that allows up to 50 messages. Upgrading to unlimited messages costs $3.99.

Screenshots of the ebcTech RTL-SDR Pager App
Screenshots of the ebcTech RTL-SDR Pager App

Turning a Smartphone’s Speaker Amplifier into a Silent Intentional VHF Morse Transmitter

Thank you to Efe Işık (TA1EEI) for writing in and sharing with us his open-source project showing how to turn a modern Android smartphone’s internal Class-D speaker amplifier into a silent, intentional VHF Morse transmitter. Efe writes:

By pushing inaudible 21 kHz full-amplitude PCM audio via Android's AudioTrack, the amplifier's PWM switching circuit radiates near-field RF harmonics into the 144 MHz (VHF) band. The signal is strong enough to be received in AM mode on common SDRs and BK4819-based handheld transceivers (such as the Quansheng UV-K5) simply by placing the antenna near the speaker grill.

Everything is open-source, requires zero Android permissions, and includes instructions on receiver setup and frequency alignment.

With the software running on the Android device, simply use an SDR or handheld radio to look for the signal in the 144 - 146 MHz region. Increasing the volume can help increase transmission power.

This reminds us of the TrojPix project, a more sophisticated method that uses a program on a PC to imperceptibly modulate pixels on a screen, effectively turning video cable/screen EMI into an air-gapped data transfer path.

AVARE ADS-B Receiver for Android Updated

All the way back in 2014, we posted about Avare ADS-B Receiver, which back then was a simple RTL-SDR ADS-B receiver and map for Android devices. The author of this app, TFL, recently wrote in and shared that the app is now a modern, fully featured ADS-B app, having added many new features such as UAT decoding with aviation weather products and NEXRAD weather radar/lightning strikes shown on the map, aircraft pictures, better SDR support, traffic filters, and audio alerts.

ADSB Receiver lets you collect live air traffic data directly on your Android device using any RTL-SDR (RTL2832U) dongle and an OTG cable. No cloud. No fees. Just raw RF decoded in real time.

  • Dual-band reception — 1090 MHz Extended Squitter (ES) for worldwide traffic, and 978 MHz UAT for US general aviation traffic plus integrated weather products (METAR, TAF, PIREP, SIGMET, AIRMET, WINDS, NOTAM)
  • Live aircraft details — tap any target on the map to pull a live photo alongside aircraft type and registered operator
  • NEXRAD weather imagery — receive official NEXRAD radar images over UAT 978 MHz
  • Network send/receive —
    • Forward all received data to any GDL90-capable EFB app (AvareX, ForeFlight, iFlyGPS, DroidEFB, and others)
    • Stream dump1090/dump978 frames to any SDR tool on your network, or ingest from an external source
  • Bias Tee and Gain support — power an external LNA or active antenna, adjust Gain as needed
  • Proximity alerts — configurable range-based traffic warnings with optional callsign filtering; useful for drone pilots monitoring airspace
  • Data logging — save all received data
  • Metric support — instead of imperial values

Webpage: https://hiz.ch/index.php/adsb-receiver-avare-adsb

Play Store Links:

https://play.google.com/store/apps/details?id=bs.Avare.ADSB
https://play.google.com/store/apps/details?id=bs.Avare.ADSB.Pro

AVARE ADS-B Receiver Android App
AVARE ADS-B Receiver Android App

VibeSDR Jr: Apple Watch RTL-SDR, KiwiSDR, UberSDR Client now Available

Back in July, we posted about VibeSDR, an AI vibecoded open-source mobile SDR client for rtl_tcp and UberSDR/KiwiSDR/OpenWebRX servers developed for iOS and Android. In that post, Stuart also mentioned that he was developing an Apple Watch app version of VibeSDR that runs directly on an Apple Watch, allowing you to view and listen to the spectrum on your wrist.

The Apple Watch version, called VibeSDR Jr, is now available as a full standalone Apple Watch App, meaning that no iPhone is required. The app costs £0.99 (~US$1.35). As before, Stuart has provided us with 20 free giveaway codes for the VibeSDR Jr App, so be sure to comment on either this post, the Facebook post, or the X post for a chance to win one of the codes.

Stuart has also noted that he now has a live VibeSDR demo running at demo.vibesdr.net, allowing users to see VibeSDR's DSP and server functionality in action. Stuart writes, "There is an RTL-SDR V4C, SDRPlay RSP1B, and AirSpy HF running on that demo server, all connected to the same AirSpy YouLoop with LNA antenna setup. The RSP1B is locked to 2.8MHz - 10.8MHz and can handle 10 users and the RTL-SDR & AirSpy are unlocked frequencies but 1 user at a time, each user gets a 30 minute time slot to play with. All the built in decoders are available and for the FM-DXers there is a full advanced RDS suite measured against a professional broadcast analyser too."

He also notes the following to avoid confusion with the software in the VibeSDR family:

VibeSDR + Buddy: The Main VibeSDR app and the Apple Watch Remote control companion app for that app.
VIbeSDR Jr: The full standalone Apple Watch SDR client no iPhone required
VibeServer: Built in to Android and standalone apps which allow you to quickly and easily share your SDR’s on a network

Use VibeServer to connect your radio and serve it and then use Jr to listen to it on your wrist, or if you don’t have your own radio Jr is compatible with almost all the same servers as the main VibeSDR app, the only thing it cannot do due to bandwidth/processing requirements is anything that is RAW IQ such as RTL-TCP or SpyServer.

Finally, Stuart notes that the Android version is coming soon and is currently just pending acceptance on the Google Play Store.

VibeSDR Jr - SDR Client for the Apple Watch
VibeSDR Jr - SDR Client for the Apple Watch

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