In one of his latest videos Matt from the Tech Minds YouTube channel tests out the "Jstvro" handheld spectrum analyzer which can be found on sites like Banggood and Aliexpress (the device is cheaper on Aliexpress) for about US$127.50 for the single antenna model, and US$165 for the dual antenna model including shipping. The device appears to be a clone of the RF Explorer, which is a spectrum analyzer that has been on the market for several years.
A spectrum analyzer can be used to visualize the RF spectrum and find frequencies that are active. It cannot demodulate signals like an SDR.
The Jstvro spectrum analyzer covers 240-960 MHz on the first port and 15 - 2700 MHz on the second port, with a total visible bandwidth of anywhere between 112 kHz to 600 MHz. It comes with a single color illuminated LCD screen.
In the video Matt gives an overview of the spectrum analyzer and shows it operating. He notes that the USB-C connection to the PC does not appear to be working and Matt was unable to find the PC software or firmware updates mentioned in the manual. In the rest of the video Matt demonstrates the 2.4G WiFi analyzer feature, the spectrum analyzer feature and goes over the settings.
Visualize the RF Spectrum With This Handheld Spectrum Analyzer
Having worked on RF communications systems before, Damian knew that the same concepts apply no matter what the physical layer of communication is. His system called SDU-X uses two ultrasonic transducers mounted on 3D printed parabolic dish's to increase the directional gain, and an Arduino Nano with amplifiers and a Digital to Analog (DAC) converter for the ultrasonic transmission.
His post explains the hardware and protocol implementation, as well as explaining the Arduino code that he's released for free. The code and 3D printer models can be found on Thingiverse.
SDU-X: A software defined ultrasonic communications system.
Videos of talks from the Software Defined Radio Academy 2023 (SDRA23) conference have recently been uploaded to YouTube. SDRA23 was held during the HAMRadio World Fair in Friedrichshafen, Germany during June 2023.
The talks appear to be slowly releasing on YouTube and currently about eight talks have been released with more to follow. Make sure you subscribe to their YouTube channel to be notified when more talks are released.
Some currently released talks of interest include:
Andreas Spiess, HB9BLA: SDR-A Keynote. SDR: What is next ?
Laurence Barker, G8NJJ: Completion of the Saturn SDR
G3ZIL & G4HZX: Propagation path analysis on HF, using SDR and FST4W
Rob Robinett, AI6VN: Creating a LCHP FST4W/WSPR beacon using RFzero or QPR Labs QDX
Gerhard Häring, DK6RH: Selfmade Portable HF-TRX with Hermeslite2 and Rasp Pi
Back in July 2021 we posted about the RadioBerry HF SDR Transceiver Raspberry Pi Hat which is an open source project by PA3GSB. It is based on the AD9866 chip which gives it a 12-bit ADC with one RX and one TX channel, a maximum bandwidth of up to 384 kHz, and an operating frequency range of 0 to 30 MHz.
Because of FPGA component shortages, the device has been out of stock and stagnant for a long time. However, recently a new version has been released by well known SDR hardware cloner Justin Peng and is now available for sale on Aliexpress for US$155. As the design for this project is open source, Justin's new version is legal and he has released the redesigned open source files on his GitHub.
In his latest video, Matt from the TechMinds YouTube channel tests out this new board. He starts by explaining the history of the RadioBerry, and shows how to set it up and install the software. He goes on to demonstrate it receiving some HF signals, transmitting on 3 kHz and 5 kHz, and how to run it standalone on a Raspberry Pi 4 with screen.
Thank you to Stéfane Perraud, Aram Kebabdjian and team for submitting news that they have recently launched an art project in Lausanne, Switzerland called "Hystérésia". The installation is technical art, which consists of an autonomous satellite receiving station designed to receive beacons from old "zombie" satellites, and then broadcast their signals audibly. A description of the ground station can be seen here.
Zombie or Dead satellites are satellites that are officially decommissioned and powered down, but have unintentionally reactivated. This often happens as over time the batteries on these satellites can undertake a chemical reaction from thousands of solar recharge cycles which eventually results in a short circuit. Hence the satellites reactivate when in sunlight. If you are interested we have an old post on this phenomena back from 2014.
The system is based on an antenna rotator with two Yagi's that tracks the zombie satellites as they pass over the sky. A QFH antenna has also been spotted in their images. Based on the waterfall images, an SDRplay RSP is used as the receiver, and some computing device is used to demodulate the signal into audio. Stefan adds:
Technically we are using a double yagi 137 and 145 plus a 777 antenna from diamond to catch 200 mHz
We developed a python based software that’s controlling a sdr software based on gnu radio.
We update TLE everyday, our azimuth and élévation rotor follow the satellites and we catch the signal with a sdr uno, plus a switch that choose antenna with the good satellite.
The machine is monitored by a bench of sensors , wind, humidity, temp. It can be control by internet via the website
The machine search for peaks around the chosen frequency, Also the sound is processed by max/msp, we denoise it and we make music out of it
The 3 metallics pavillons blows the sound noise to the audience Each time a satellite shows up, the machine sends a story told by one of our recording, a woman actors voice , it tells a specific history that’s tells a narrative about the satellite that’s on air … but in French
If you are unable to visit the installation in person, it appears that their website also broadcasts the last received satellite's sound. The website also shows photos of the history of the zombie satellites.
If you're interested in other art based on satellites and software defined radios, have a look at our previous post on the open weather project, and the "signs of life" project. Another SDR art project was 'Holypager', an art installation that continuously prints out pager messages received by a HackRF, and "ghosts in the air glow" project which used the HAARP antenna array to broadcast an art project.
The DeepSDR 101 V1 was a handheld software defined radio with built in LCD screen, a tuning range of 100 kHz - 149 MHz, and a bandwidth of 192 kHz. It appears to be an original design by Chinese company Hangzhou Minghong Electronic Technology Co., Ltd.
Currently the DeepSDR 101 Version 1 has been discontinued while they work on Version 2. However, recently clones called the "SDR 101" have begun appearing on various marketplace sites.
In his YouTube video, Matt from the TechMinds video checks out one of these SDR 101 clones. Matt shows some HF reception, however has some issues with the PC USB connection. Ultimately Matt does not recommend the device, being a clone, having USB connection issues, and having mediocre performance for the price. Instead Matt would consider a Malachite-SDR instead.
SDR 101 - DSP Receiver That's Cloned More Than Dolly
Thank you to Marc for submitting news of his new project called IQEngine. IQEngine is a free open source web project that allows users to upload IQ recordings of various signals, and share them. The idea is to over time build up a huge database of signals based on IQ data which may be useful for identifying unknown signals, testing decoders and training machine learning databases.
IQ data is essentially the raw radio data from software defined radios before any demodulation or decoding is done. By recording IQ data any demodulation method can be applied to it later. However IQ data does not contain any metadata about the signal itself. To solve this, IQ Engine are using the Signal Metadata Format (SigMF) which allows for information about the IQ recording to be encapsulated along with the IQ recording itself.
The IQEngine web interface includes an easy way to rapidly view and analyze huge IQ recordings, and allows users to annotate them too. At the moment the project is still in the early stages and looking for interested contributors to the FOSS project.
Marc writes:
We're hoping for it to become like a SigIDWiki on steroids, where people can share and learn about different signals using an interactive spectrogram (inspired by Inspectrum), all in the browser so that there's nothing to install. We are putting a lot of emphasis on education and ease-of-use.
There will also be plugins that allow for running signal detection/classification implementations on the signal recordings, to facilitate RFML research, although these plugins could also be used for demod/decoding/etc.
The tool builds off the SigMF standard for metadata, and it works with binary IQ files.
Right now we're mainly looking for more folks to help out with early development, it's really fun working on a FOSS project in the early stages because there are so many design decisions to be made and anyone has potential to step in and make huge contributions and impact the direction the project goes. The code is mostly javascript and python. Anyone interested can join the discord or email [email protected].
IQEngine Display Cellular Downlinks with Annotations
URTI will offer radio amateurs, researchers, educators, and professionals an affordable, compact RF test tool that could be used in place of multiple expensive pieces of traditional radio test equipment.
Our goal for URTI is to design a single hardware platform capable of serving as many popular types of one-port or two-port RF test instruments. We plan to build a directional coupler into a wideband, full-duplex SDR platform to enable URTI to function as a:
spectrum analyzer
vector network analyzer
vector signal generator
vector signal analyzer
antenna analyzer
power meter
frequency counter
full-duplex SDR transceiver
The design and hardware of the URTI appear to still be in the very early stages, with nothing other than early component lab tests released yet. However, given the track record of GSG products, we expect that they will release a high quality and completely open source product in time. We look forward to tracking the progress of the URTI.
