In the past we've posted several times about how 1.42 GHz Hydrogen Line amateur radio telescopes used with RTL-SDRs or other SDRs for Hydrogen line observations of the galaxy. Recently Hackaday ran a post highlighting a project from "PhysicsOpenLab" describing an 11.2 GHz radio telescope that uses an Airspy SDR as the receiver.
Celestial bodies emit radio waves all across the radio spectrum and typically observations can be made anywhere between 20 MHz to 20 GHz. Choosing an optimal frequency it is a tradeoff between antenna size, directivity and avoiding man made noise. For these reasons, observations at 10-12 GHz are most suitable for amateur radio telescopes.
The posts by PhysicsOpenLab are split into two. The first post highlights the hardware used which includes a 1.2m prime focus dish, and 11.2 GHz TV LNB, a wideband amplifier, a SAW filter, a bias tee, and the Airspy SDR. The LNB converts the 11.2 GHz signal down to 1.4 GHz which can be received by the Airspy. Once at 1.4 GHz it's possible then to use existing commercial filters and amplifiers designed for Hydrogen line observations.
The second post explains the GNU Radio based software implementation and the mathematical equations required to understand the gathered data. Finally in this post they also graph some results gathered during a solar and lunar transit.
Finally they note that even a 1.2m dish is quite small for a radio telescopic, but it may be possible to detect the emissions from the Milky Way and other celestial radio sources such as nebulae like Cassiopeia A, Taurus A and Cygnus A a radio galaxy.
GNU Radio is an open source digital signal processing (DSP) toolkit which is often used in cutting edge radio applications and research to implement decoders, demodulators and various SDR algorithms. Version 126.96.36.199 has recently been released. Below is part of the release text, but please see the official release post for the full list of changes.
The future is not set, there is no fate but what we make for ourselves. In this very spirit, GNU Radio 3.9 packs a whole bunch of power when it comes to transforming the way GNU Radio and its ecosytem can be developed in the future.
Not only did we have great progressions from old dependencies that proved to be all too problematic (SWIG, Python2), but also did we see an incredibly influx of people actively working on how maintainable this code base is. This will nurture the project for years to come.
All in all, the main breaking change for pure GRC users will consist in a few changed blocks – an incredible feat, considering the amount of shift under the hood.
GNU Radio 188.8.131.52 is out!
This significant release is focused on maintainability and code consistency, and has many new GUI elements (LED indicators, compass, Az/El plot, toggles and more!), new DSP blocks, and a variety of enhancements and fixes.https://t.co/SIpqRQuiIF
GNU Radio Days is a yearly European conference all about GNU Radio and its applications with software defined radios. GNU Radio is an open source digital signal processing (DSP) toolkit which is often used in cutting edge radio applications and research to implement decoders, demodulators and various SDR algorithms.
Thank you to Matt Knight for submitting news about the Radio Resilience Competition which is all about finding ways to building the best wireless PHY layer via SDR. Anyone around the world can participate from the comfort of their own home, as the competition is run entirely via a GNU Radio RF simulator system. Matt writes:
The Radio Resilience Competition is a community-focused Software Defined Radio competition that is all about building the most interference-resistant, highest-performance waveforms possible. Inspired by DARPA's Spectrum Challenges, it goes back to basics by focusing on the foundational layer of all wireless communications -- the PHY. Registration is open now on our homepage!
For your readers, IMO the most exciting dimension of the Radio Resilience Competition is that it takes place entirely on virtual infrastructure. We decided to design the competition this way to set the lowest possible barrier to entry, and to draw the biggest competitor pool possible. DARPA's challenges relied on big expensive RF emulators built on real radios and supercomputers which, despite being immensely cool, capped the total number of competitors and had some material drawbacks. Furthermore, we open sourced our RF simulator so competitors can run it locally and rapidly iterate on their designs. We hope the simulator will have uses beyond the competition as well.
The Radio Resilience Competition is organized by Sytse Sijbrandij, who in an entirely separate capacity from running this competition is also the CEO of GitLab. Sid envisioned the competition after learning about unlicensed spectrum and becoming an SDR hobbyist himself.
We presented the Radio Resilience Competition at GNU Radio Conference on Monday. Here's a link to our talk if you are interested -- it goes into more detail about the conception of the competition, as well as the infrastructure we built for it.
The institute for the Search for Extraterrestrial Intelligence (SETI) and GNU Radio are joining forces. SETI are an organization that uses radio telescopes to search for radio signals that may have been generated by extraterrestrial intelligence. As part of a transition from proprietary hardware to cheaper more capable off the shelf hardware such as USRP SDRs and GPU processors, SETI are beginning to make more use of the open source GNU Radio DSP processing suite. The use of GNU Radio will also allow other researchers and hobbyists at home to possibly help with their own analysis.
In the Zoom meeting below SETI and GNU Radio leaders discuss the partnership, also noting the importance RTL-SDRs have played in the advancement and popularisation of GNU Radio, as well in the general advancement of radio education.
This is just a reminder that the 2020 GNU Radio Conference will be held online in a few days time starting on September 14 and ending September 18 2020. Viewing the live talks and participation in the discussion forums is free for everyone around the world, however you must register first via their site. The paid $50 workshops are all currently booked however you can go on the waiting list in case more spaces are opened.
GNU Radio Conference (GRCon) is the annual conference for the GNU Radio project & community, and has established itself as one of the premier industry events for Software Radio. It is a week-long conference that includes high-quality technical content and valuable networking opportunities. GRCon is a venue that highlights design, implementation, and theory that has been practically applied in a useful way. GRCon attendees come from a large variety of backgrounds, including industry, academia, government, and hobbyists.
GRCon20 will be held starting September 14, 2020 online as a virtual event. The organizing team is hard at work to create a fun and interactive experience.
Our keynote speakers include: Becky Schoenfeld W1BXY, managing editor of QST magazine, Oona Räisänen [ windytan ] hacker of signals and computer programmer, and Jim St. Leger, Director Open Source, Intel.
With an annual program that has broad appeal, GRCon attracts people new to Software Radio just looking to learn more, experts that want to keep their finger on the pulse & direction of the industry, and seasoned developers ready to show off their latest work.
Titles of the talks scheduled are shown below. The full list of talks, workshops and descriptions can be found here.
Oona Räisänen - Video Decoding Adventure
Introducing OpenCPI as an Infrastructure for GNU Radio and GNU Radio Companion
How Strong is my SDR Signal?
Introducing the Radio Resiliency Competition
Are We Alone? How GNU Radio Can Help Us Find ET
A Conversation with the Ettus Research / NI SDR R&D Team
Enabling Performance Portability of GnuRadio on Heterogeneous Systems
Architecture Update - Marcus Mueller
Becky Schoenfeld - Keeping Ham Radio Alive and Well: ARRL’s Education Initiatives
ESA's OPS-SAT Mission: Powered by GNU Radio
Designing a Narrowband Radar using GNU Radio and Software Defined Radio for Tomography and Indoor Sensing
The De-Swiggification of GNU Radio
Exploring RFNoC with the UHD Python API
Teaching the Principles of Time Delay Spectrometry Ultrasound with GNU Radio
Ultra-cheap SDR Digital Television Transmission: ISDB-T with an osmo-fl2k and an RTL-SDR
Software defined radio based Synthetic Aperture noise and OFDM (WiFi) RADAR mapping
Community Continuous Integration (CI) for GNU Radio
RadEOT: The Radio Education Outreach Tool
Software defined radio based Global Navigation Satellite System real time spoofing detection and cancellation
SDR to GPU Peer-to-Peer Data Streaming for Cognitive Radar and EW Use-Case
Security Analysis of Zigbee Networks with Zigator and GNU Radio
Thank you to M Khanfar for submitting his video that shows a step-by-step tutorial on building your own SSB receiver in Windows GNU Radio for QO-100 satellite reception. His tutorial includes adding several tuning sliders in the GNU Radio GUI as well.
QO-100 / Es'hail-2 is a geostationary satellite at at 25.5°E (covering Africa, Europe, the Middle East, India, eastern Brazil and the west half of Russia/Asia) providing broadcasting services. However, as a bonus it has allowed amateur radio operators to use a spare transponder. Uplink is at 2.4 GHz and downlink is at 10.5 GHz. We note that we are selling a "bullseye" LNB in our store which allows most SDR dongles to be able to receive the signal with high frequency accuracy.