Tagged: sdr#

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

Receiving the ‘Hidden’ Broadcast FM SCA Audio Subcarrier with an RTL-SDR and SDR#

Broadcast FM channels can often contain additional subcarriers hidden within the bandwidth. A common subcarrier is Radio Data System (RDS), and this is what provides song and radio station text information to your radio.

Another less commonly seen subcarrier is the Subsidiary communications authority (SCA), which is a separate audio channel hidden within the broadcast FM signal. SCA is typically used for niche radio programs, elevator music, music for doctors offices, and niche services such as reading for the visually impaired. In the past you needed a special hardware SCA radio to receive these channels, however receiving these channels with an SDR is relatively simple. Not all broadcast FM stations will have an SCA service, but the video shown below explains how to find one.

Over on YouTube channel Double A has uploaded a video showing how to decode these SCA subcarriers using an RTL-SDR, two SDR# instances and the MPX Output plugin. The idea to to use a virtual audio cable to pipe the FM Multiplex (MPX) audio output from one instance of SDR# to another. In the second SDR# instance you can then directly tune into the SCA channel. In his video he also explores the FM MPX spectrum, showing the different components, and also how to install and use RDS Spy for decoding RDS.

Tuning an FM Audio Subcarrier (SCA) & Decoding RDS Data with RTL-SDR USB

SDRSharp Guide V3.0 Released

Paolo Romani (IZ1MLL) has recently released version 3.0 of his SDRSharp PDF Guide which we posted about last in March of this year. As before the document is a detailed guide about how to use SDRSharp, which is the software provided by Airspy. While intended for Airspy devices, SDRSharp also supports a number of third party SDRs, including the RTL-SDR, and it is the software we recommend starting with when using an RTL-SDR.

The guide is now 61 pages long, and covers all the settings, UI customization, included and third party plugins, and use of some external decoders.

SDRSharp Guide

SignalsEverywhere: Testing SDR++ A Hands on Overview

On on YouTube on the SignalsEverywhere channel Sarah has uploaded a new video where she gives a hands on overview of the SDR++ software. Last week we posted about the release of SDR++ V1.0.0, which is an open source, cross platform, C++ based GUI general receiver program for various SDRs including the RTL-SDR.

In the video Sarah shows it's basic usage in action and highlights many of the great features that SDR++ has. Overall Sarah notes that she is very impressed with SDR++, praising it as one of the best SDR applications released in a while, and we agree.

SDR++, The Cross-Platform bloat-free SDR software | A Hands on Overview

SDR++ Version 1.0.0 Released

SDR++ is an open source, cross platform, C++ based GUI general receiver program for various SDRs including the RTL-SDR. Since it's alpha release in mid 2020, it has undergone huge amount of development, and is quickly becoming the main program of choice for many users due to it's efficiency, cross platform and multi-SDR hardware support and increasing feature set. And with an easy GUI very similar to that of SDR#, it's easy for most users to learn.

Recently version 1.0.0 of the SDR++ software has recently been released. This is the first non-beta stable version, so represents a major milestone in development. Over on Reddit programmer u/xX_WhatsTheGeek_Xx summarizes the latest developments.

After over a year of work, I'm proud to released version 1.0.0 of SDR++!

For those who don't know, SDR++ is a crossplatform (Windows, Linux, MacOS, BSD) and open-source (https://github.com/AlexandreRouma/SDRPlusPlus/releases) general purpose receiver software meant to be simple and easy to use. It has advances features like multi-vfo and uses a fully custom DSP making it very efficient.

Here are the following additions compared to the last version:

  • Support for the SpyServer protocol
  • Support for all SDRplay devices
  • Support for all BladeRF devices
  • Support for all LimeSDR devices
  • Optional IQ correction
  • Optional Decimation
  • Broadcast FM Stereo
  • Frequency manager to create lists of frequency and optionally display them directly on the FFT/Waterfall
  • Network sink to stream the audio output via TCP or UDP
  • Options to set the FFT framerate, FFT size and FFT window.
  • Theming with Dark and Light themes supplied by default
  • RigCTL server module to control SDR++ from, for example, gpredict.
  • A bunch of keyboard shortcuts (see wiki on the github page)
  • SNR meter
  • More info when hovering a VFO
  • Colored VFOs to easily identify which is which at a glance
  • Meteor M2 demodulator compatible with LRPTOfflineDecoder and Satdump
  • Ability to resize VFOs by directly dragging the sides on the FFT and waterfall
  • Module manager to easily add or remove any module on the fly without having to restart or edit the config manually
  • File dialogs to select directories in the recorder or files in the file source (instead of having to type in the path)
  • Ability to disable modules that support it (Radio and Meteor M2 demodulator) with one click (to save CPU power or just if they're not needed)
  • Lots of performance improvements
  • Ludicrous amounts of bugfix :)

I'd like to thank the many contributors, patrons and companies (SDRplay, Airspy, Nuand, LimeMicro) who helped make this project possible!

If you have any issue with the software, please open a github issue or contact me directly on the SDR++ discord (see readme on github)

I hope this software comes in useful to at least some of you ;)

We also wanted to highlight the fact that SDR++ runs smoothly with about 50% CPU usage on a Raspberry Pi 4 with an RTL-SDR.

Also according to @cemaxecuter who created DragonOS, if rtaudio is installed on Linux , then an easy to use virtual audio sink becomes usable from SDR++, allowing audio to be easily passed to other programs such as WSJT-X just like on Windows.

A ready to use zip file for Windows is available on the GitHub Releases page, as well as amd64 .deb and .pkg install files for Ubuntu, Debian and MacOS systems. For other systems the compilation instructions are available on the readme or Git main page.

SDR++ V1.0.0 Screenshot

Lessons Learned Using SDR in the Classroom

Recently SDR-Boston hosted an online panel titled "Lessons Learned – Using SDR in the Classroom", and the video is now up on YouTube. A presentation was given by three panelists and moderator on the topic of how software defined radio has been used in University curriculum. Many of the courses make use of RTL-SDR dongles, as well as more advanced transmit capable SDRs.

Software-defined radio (SDR) technology is extensively being used across a wide range of research activities to help demonstrate feasibility of new algorithms and approaches that are rapidly defining the new current state-of-the-art in emerging wireless technologies (e.g., 5G/6G, drone networks) as well as providing new opportunities to explore the electromagentic (EM) spectrum world around us (e.g., radio astronomy, satellite communications, radar). Although SDR has become mainstream in research activities, it has not been widely used in the classroom environment to help students leap from theoretical concepts to practical hands-on learning.

The following presentations were given (more information available on the panel website):

1,024 ways to teach with SDR: Dr. Fraida Fund, New York University

Educators who are considering using software defined radio in the classroom face a dizzying array of choices, including hardware, software, and curriculum decisions. In this presentation, I will describe my experiences using software defined radio in different ways for a range of audiences, from high school to graduate school. I will share the decisions I made in designing each course or curriculum module, and the tradeoffs associated with those decisions.

Teaching SDR and DSP to Undergrads within CS: Dr. Marc Lichtman, University of Maryland

Dr. Lichtman will briefly discuss the course he designed and taught at The University of Maryland within the CS dept, introducing students in their senior year to SDR and DSP, as an elective. The first half of the course acts as a DSP and wireless comms primer, essentially condensing several courses that are normally taught at the graduate level within ECE, providing students with the necessary background by teaching DSP theory using diagrams, animations, practical demos, and code examples rather than a mathematically rigorous theoretical approach. The remainder of the course focuses on using SDRs to implement the DSP techniques they had learned. He has recently created a free online textbook based on his course, teaching SDR and DSP with Python, https://pysdr.org.

Teaching Introductory Communication Systems using SDR: Challenges, Benefits, and Lessons Learned: Dr. Cory J. Prust, Milwaukee School of Engineering

Exposure to software-defined radio (SDR) technology is a valuable experience for undergraduate electrical and computer engineering students. Decreasing hardware costs and easy-to-use software tools have made SDR experimentation readily available to the undergraduate laboratory setting. However, especially for students who are still learning the fundamentals of communication systems, laboratory exercises must be carefully designed to reinforce foundational concepts, meaningfully engage and motivate students, and be presented at an appropriate technical level. This presentation will describe the development and deployment of hands-on SDR-based laboratories used in an introductory communication systems course. Lessons learned from multiple offerings of the course will be discussed.

Hands-On Wireless Communications Education: It’s More Than I/Q Representation: Dr. Alexander M. Wyglinski, Worcester Polytechnic Institute

In most undergraduate and graduate courses focusing on digital communication systems engineering, the concept of representing all information in terms of in-phase (I) and quadrature (Q) comes up and becomes the foundation for many other concepts taught throughout the rest of the course. However, the treatment of I/Q tends to be over idealized and the real-world effects affecting this very important source of information is saved “for the next course”. With SDR technology, those real-world effects that are impacting the successful recovery of I/Q samples are experienced right away and the true challenges of digital communication systems engineering are experienced first hand. This introduction will provide some initial insight on the practical considerations when extracting I/Q samples from over-the-air and attempting to decode them for the purposes of recovering binary information.

SDR-Boston Panel Event: "Lessons Learned - Using SDR in the Classroom"