Tagged: sdr#

SignalsEverywhere: Review of SDR++ on Android

In our last post we mentioned that a 'pre-release' public version of SDR++ for Android was recently released. Now over on the SignalsEverywhere YouTube channel Sarah has uploaded a new video where she reviews and demonstrates the new SDR++ Android App. 

In the video Sarah demonstrates how to connect and start a SDR, shows SDR++ in action, then tests listening to NOAA weather audio reports, Inmarsat reception via the bias tee support, P25 and broadcast FM. She also shows how it's possible to use the split screen multitasking feature on Android to send audio from SDR++ into APRSdroid for APRS decoding.

She goes on to show how to fine tune the screen PPI resolution for different sized devices, and how to set up multi-VFO listening on the HF bands. Next, she compares the audio decoding quality between SDR++, SDRTouch and RFAnalyzer. Finally she shows that a HackRF running at a wideband 20 MHz of bandwidth can run smoothly. 

The Android SDR App That Beats Them All! Supports RTL-SDR Airspy HackRF and Many More!

SDR++ Android App Public Pre-Release Now Available

SDR++ is an open source program compatible with most software defined radios including the RTL-SDR that has been going through rapid development making it now one of the top software choices.

Yesterday a public 'pre-release' Android version of SDR++ was made available for download. The release is announced as a 'pre-release' due to various bugs still existing. However, we note that we have been testing a private release for the past few weeks, and we can say that it is working great most of the time. The Android App replicates most of the desktop experience perfectly, and it operates very smoothly on most modern devices.

The author Alexandre Rouma writes:

I'm happy to release the first public pre-release of SDR++ for android. It's still quite early and has a few bugs and quirks that you might run into:

  • SDR MUST be plugged in before starting SDR++ and you MUST press refresh in the SDR source you're using before pressing play if you first plugged in the SDR or unplugged/replugged, otherwise expect a crash. The USB handling still needs some work.
  • There are still a few UI glitches
  • There is no easy way to select a path for recording or file for playback
  • The audio sink on Android may have higher latency
  • All menus sometimes close when app goes in the background.
  • Resizing the menu and/or waterfall is kinda fiddly, be precise when trying to grab the resize bar!!!
  • At some size menu sizes, the app crashes. If this happens, start in landscape
  • On Samsung devices, the keyboard doesn't always work for some obscure reason...


  • Android 9.0
  • OpenGL 2.1

Since phones usually have a high screen resolution, set the DPI scaling in the Display menu or you'll have a hard time using the app.

Current Device/Protocol Support:

  • Airspy
  • Airspy HF+
  • HackRF
  • PlutoSDR (network only)
  • RFspace
  • SDR++ Server
  • SpyServer

In any case, I'd love to get some feedback on it, so feel free to try it out and let me know!

Download Here:https://drive.google.com/file/d/1Z2HPG8RQt8QXsznAq85oewb6TI1lKaL3/view?usp=sharing

PS: If you like this work, feel free to support me on Patreon, since putting it on the App Store won't be cheap and I want to make sure it's completely free with no ads!

SDR++ Android App Screenshot. Credit: goscickiw https://github.com/AlexandreRouma/SDRPlusPlus/discussions/703

New York Times Story on Intercepted Russian Forces Radio Communications

The New York Times have recently run an incredible video story about how Russian radio communications are being intercepted and recorded by ham radio operators and open source radio monitoring hobbyists in Ukraine. Some of the communications reveal the extent of the logistical issues experienced by the invading forces, and perhaps have even recorded evidence for war crimes.

It appears that much of the invading Russian forces use simple unencrypted analogue voice over HF channels that can be intercepted and recorded by anyone with an HF software defined radio, or anyone willing to monitor nearby web-based SDRs like KiwiSDRs and WebSDRs. In the video screenshots of recordings played back in SDR# and various WebSDRs are displayed.

The story focuses mostly on the audio recordings that highlight communications between Russian forces discussing attack plans, including plans to bombard residential areas with artillery. These recordings are cross-referenced with reports and videos of actual tank sightings and destruction in the areas discussed on the radio.

A later recording highlights communications from a distressed Russian vehicle under attack, requests for air support being unfulfilled, and urgent requests for supplies like fuel, food and water. 

Russia Struggled to Capture a Ukrainian Town. Intercepted Radio Messages Show Why.

Some of the monitoring projects involved are highlighted in the story and they include, Project Owl, Ukrainian Radio Watchers, ShadowBreak and NSRIC (Number Stations Research and Information Center). We are also aware of at least one other organization attempting to record communications within Ukraine as well that may be making use of RTL-SDRs, HackRFs and other SDRs.

Running an RTL-SDR on an old OpenWRT Router

With the rising cost of computing hardware like Raspberry Pi's, Jaime Badillo decided to instead make use of one of a cheap old router, and set it up as an RTL-SDR server. To do this, Jaime took his old router and installed on it the free open source firmware OpenWRT, which is essentially a Linux operating system. Once this was completed, he was able to SSH into the router and install the RTL-SDR drivers and rtl_tcp software just as he would with a Raspberry Pi 4.

Jaime has uploaded a tutorial document that shows how to installed OpenWRT, how he configured the network settings and how he installed the RTL-SDR drivers and connected to rtl_tcp remotely via SDRSharp. The tutorial is written in Spanish, however we have uploaded an English Google translated version here. Jaime has also uploaded a YouTube video showing the router server in action.

SDR# receiving data from rtl_tcp running on an old router.

SDR++ Server Beta Now Available

SDR++ is a general purpose receiver program compatible with almost any software defined radio including the RTL-SDR. Recent developments have seen the author release a beta of  "SDR++ server" which is a program that allows users to access SDRs remotely, by connecting to them over a network connection. This is similar to existing server applications like rtl_tcp and Spyserver, however like SDR++ itself, SDR++ Server is compatible with almost any SDR and that is a major drawcard.

The server is still in development and the author notes that he is still working on adding new features like lossless compression techniques in order to reduce network bandwidth requirements. However, it has already seen to be running well in tests with a remote server positioned half way around the world, even without compression enabled.

We note that SDR++ author 'Ryzerth' has a Patreon. If you like seeing these SDR++ developments please consider support him.

TechMinds: Testing SDR++ The Bloat Free SDR Software

Over on YouTube TechMinds has recently released a video where he overview SDR++, dubbed as the "bloat free SDR software". We've been following the development of SDR++ for a while, and recently posted about the release of version V1.0.0. SDR++ is an open source, cross platform, C++ based GUI general receiver program for various SDRs including the RTL-SDR. In another recent post we also saw a video review from Sarah at SignalsEverywhere.

The the video TechMinds gives an overview of the SDR++ features and GUI, and also shows DSD+ and WSJT-X running together with it. He notes that SDR++ lives up to it's expectations and lives up to it's bloat free tagline.

SDR++ Multi Platform SDR Application

SDR Talks from the SDRMakerspace Online Presentation

Thank you to Robert for letting us know about these videos from the "ESA ARTES SDR MakerSpace Presentations" from September 6-8, 2021 which are now available on YouTube. 

Libre Space Foundation ( Greece) and the Institute of Reconfigurable & Embedded Digital Systems(REDS) of the Haute Ecole d’Ingénierie et de Gestion du Canton de Vaud – HEIG-VD (Switzerland) have been implementing a number of smaller projects as part of an Software Defined Radio MakerSpace of the European Space Agency.

This activity is part of the ARTES programme of ESA that supports innovation in satellite communications.

The findings were presented in three 2-hour slots in the afternoon at 15:00 CEST (for which you are requested to register separately) on Mon 6, Tue 7 and Wed 8 September 2021.

  • Monday 6 Sep was focused on the evaluation of various SDR boards and FPGA tools chains. High-rate direct sampling by SDR’s and SDR on Android will also be presented.
  • Tuesday 7 Sep was dedicated to building blocks that have been implemented as open source developments for Gnuradio, such as gr-leo, gr-ccsds, gr-soapy etc.
  • Wednesday 8 Sep was mainly about the combination of SDR and AI/ML to do signal detection and classification. In addition, an SDR testbed and spectrum monitoring will be presented.

The talks cover various SDR topics related to satellite observing. Some talks we were interested in are highlighted below, but the full list can be found on the SDRMakerspace website, or the SDRMakerspace playlist on the Libre Space Foundation YouTube channel.

SDRMakerspace - SDR on mobile

Talks and Poster Presentations from the HamSCI 2021 Virtual Workshop

HamSCI is an organization dedicated citizen radio science and specifically the "publicity and promotion of projects that advance scientific research and understanding through amateur radio activities". Back in March they held their HamSCI 2021 workshop online, and the videos from presentations and posters are now all available on the Ham Radio 2.0 YouTube channel.

Most of he presentation videos were released back in June, but the poster talks were just released in the past few days. Many of the projects mentioned in the talks involve the use of software defined radios.

The talks include multiple presentations on the HamSCI personal space weather station project, updates on the TangerineSDR and lots of ionosphere research.

HamSCI 2021: iPoster Breakout Room 1