Over on his blog F4GOH has posted a rather comprehensive tutorial consisting of seven PDF documents showing how he's set up his Raspberry Pi for ham radio and other RF projects. The PDF's essentially form a book that starts with the very basics like preparing an OS for the Pi SD Card, powering on the Pi, finding the IP address and connecting to it with SSH or VNC.
The tutorials move on to installing and using various ham radio programs like Fldigi, WSJT-X , GQRX, GNU Radio, before going on to teach some more Linux concepts. The final two PDF tutorials cover the installation and use of OpenWebRX for remote RTL-SDR use, R2Cloud for decoding weather satellites, and finally Radiosonde Auto RX for decoding radiosonde's on weather balloons.
Just a few days prior to the 2020 GNU Radio conference, ARRL and TAPR will hold their yearly Digital Communications Conference (DCC) online. DCC is a yearly conference with many SDR and RF related talks, with a focus on ham radio science. The talks will be live streamed on YouTube for free, however you can register for $30. Registration will grant you the ability to ask questions or chat via Zoom, and includes access to the papers. The YouTube live link has not been provided yet, so keep an eye on the DCC web page for the announcement.
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
Eric had an inverted L and T3FD antenna set up in his backyard and he wanted to test both at the same time to see which received HF better overall. Rather than relying on subjective 'by ear' measurements he decided to use the digital FT8 mode as his comparison signal. FT8 is quite useful for this purpose as the decoded data includes a calculated signal-to-noise (SNR) reading which is a non subjective measure that can be used for comparisons. It also contains information about the location of the signal which can be used for determining the DX capability of the antenna.
To perform the comparison he used two or our RTL-SDR Blog V3 dongles running in direct sampling mode, and also added an additional low pass filter to prevent excessively strong TV and FM signals from overloading the input. Each antenna is connected to it's own RTL-SDR, and a modified version of GQRX with remote UDP control is used to switch between multiple FT8 frequencies so that multiple bands can be covered in the experiment. WSJT-X is used for decoding the FT8 packets.
After logging SNR values for several days he was able to plot and compare the number of packets received by each antenna, the maximum distance received by each antenna. His results showed that his inverted L antenna was best in both regards. He then performed a relative comparison with the SNR readings and found that the inverted L performed best apart from at 14 MHz, where the T3FD performed better.
In further tests he also compared the antennas on which signal headings they were receiving best from. The results showed that Erics inverted L was receiving best from one direction only, whereas the T3FD received signals from more headings.
Eric's post includes full instructions on the software setup and also Python code which can be used to replicate his experiments. We think that this is a great way to objectively compare two types of antennas.
Antenna directionality measurements via FT8 received headings
A lot of affordable Chinese clone SDRs have been coming onto the market recently, and the RX-888 is one of the most interesting. The RX-888 appears to be an improved clone of the RX-666 which in turn is a clone derived from Oscar Steila (IK1XPV)'s BBRF103 original open source design.
The RX-888 is based on the LTC2208 16-bit ADC chip which is capable of streaming the entire 1 kHz to 32 MHz frequency range to the PC over USB 3.0 with direct sampling. Frequencies from 32 MHz to 1.8 GHz can also be received via an R820T2 tuner which is on the board (the same tuner used in most RTL-SDRs). Due to the bandwidth restrictions of the R820T2 silicon, the bandwidth above 32 MHz is restricted to 8 - 10 MHz. The main change when compared to the RX-666 appears to be that there is an LNA which improves medium wave and small antenna performance which was a problem on the RX-666. The RX-888 also adds several heat sinks to the enclosure, as excessive heat generation of the LTC2208 ADC appears to also be an issue.
The RX-888 Software Defined Radio
Recently Nils Shiffhauer (DK80K) wrote up a great review of the RX-888. In the review he covers the specs, shows a few screenshots of some signals he's received and also provides multiple audio samples of signals received.
The RX-888 is currently available on marketplace sites like Aliexpress and eBay priced at around US$180. In the past SDRs that could receive the entire HF band at once were rare, with the only affordable SDR with this capability being the KiwiSDR. So it is good to see that we may now be entering a stage of new advancement in affordable SDRs.
One thing to note is that this design can be considered a clone. However the original design by Oscar is open source and from this post on his blog he seems happy and accepting of the clones.
We note that we have ordered a unit and will be uploading a review once we test it.
Android developers have a new RTL-SDR driver wrapper available to use called "RTL-SDR CP Driver". This driver by Evgeni Karalamov is designed to have an additional feature over the current Android RTL-SDR drivers in that it implements client application permission management. The overview reads:
RTL-SDR CP Driver utilises the rtl-sdr codebase and is meant to be kept in sync with the developments there. The provided interface mirrors the functionality of rtl_tcp in an Android way. Instead of via a TCP socket, the communication is carried out through file descriptors returned by a ContentProvider.
Since some potentially sensitive information could be captured through the SDR receivers, like indications of the device location, the RTL-SDR CP Driver implements permission control similar to that of the Android framework. Prior to accessing receivers, client applications have to ask the user for permission to access the driver by starting the driver's permission flow via startActivityForResult. Once the user grants access, their answer is remembered and they are not prompted again. The user has the ability to later revoke the permission from the driver's UI, accessible via the Android launcher.
The actual driver app can be downloaded from the Google Play Store. Note that this doesn't provide any functionality by itself. We will need to wait until apps take advantage of it.
Over on his YouTube channel Kalle Hallden has uploaded a video demonstrating how to perform a replay and "rolljam" attack on a wireless car key with an RTL-SDR and Yardstick One. His first experiment is a simple replay attack which involves recording the unlock signal from the car key with the Yardstick One in a place far away from the car so that it is not received, then replaying it close by.
This works well, but Kalle then explains rolling code security and how this would easily thwart any replay attack in the real world. However, he then goes on to explain and demonstrate the "rolljam" technique, which is one known way to get around rolling code security. The demonstrations are obviously not full tutorials, but are just high level overviews of how wireless security can be defeated.
Over on his YouTube channel Tech Minds has uploaded a video showing how it's possible to receive and decode GPS signals with an RTL-SDR. To do this he uses one of our RTL-SDR Blog V3 dongles and a GPS patch antenna which is powered via the bias tee on the dongle.
On the software side he uses GNSS-SDRLIB and RTKLIB to decode the GPS signal. The result of the two programs is your current GPS coordinates which can be plotted on a map. Unfortunately in the video Tech Minds was unable to get the Google Maps display to work, but you can easily type the coordinates into Google maps yourself.
