Category: Other

TechMinds: Testing New RadioBerry Productions – an HF SDR Transceiver Raspberry Pi Hat

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.


Hystérésia: An Art Installation that Listens to Zombie Satellites

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.

Hysteresia montage (click for large version)
Hysteresia montage (click for large version)

TechMinds: A Brief Review of the SDR 101, a Clone of DeepSDR 101

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

IQEngine: A Web-Based Toolkit for Sharing and Analyzing RF IQ Recordings

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.

There's a canonical instance of the site hosted at, the source code can be found at and we have a Discord (

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

Great Scott Gadgets to Develop a Universal Radio Test Instrument (URTI)

Great Scott Gadgets (GSG), creators of the HackRF, YARD Stick One and Great FET (among other products) have announced that they are developing a device called a "Universal Radio Test Instrument (URTI)". They note that:

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.

More information about the device is available at

DeFli: A Decentralized Network of RTL-SDRs on the Blockchain for UAV and Satellite Operators

Recently we came across a new project called DeFli and DeSky, which appears to be plans for a decentralized network of RTL-SDRs. The goal of the project is to provide decentralized access to ADS-B and satellite data through the use of RTL-SDR ground stations. The RTL-SDR ground stations upload their data to the DeFli servers and in return ground station hosts receive compensation in DEFLI tokens via the DeFli blockchain.

From the website it appears they are focusing on selling the data to UAV and satellite operators, but there seems to be no reason why it couldn't be used for other purposes too.

The use of crowd sourced RTL-SDR data is nothing new, with successful ADS-B aggregators like and already in operation. Projects like SatNOGs also exist which crowd source satellite data. Not to mention other RTL-SDR and radio data aggregators like for Marine AIS, for Amateur Radio Balloons, for APRS, and for ACARS, VDL, HDFL and SATCOM data. However, this is probably the first radio data aggregator to incorporate blockchain concepts for host rewards.

In a Reddit Post (now removed but cached on Google), the creators wrote:

There is clearly an appetite from a large number of Helium Hotspot owners to utilize their hotspots for other projects with a view to getting a better ROI on their investment. That being said, I believe it is absolutely just and fair for Nova & the Foundation to take steps to prohibit the LoRa specific hardware from being used by competing projects both from a commercial perspective and also regulatory. Our personal belief is that Nova/Foundation should operate Helium Network as a NaaS and allow these newer "players" to piggyback on the equipment without compromising the regulatory side of things.

From an industry perspective there is of course a frustration at an awful lot of under-used/under-utilized hardware, specifically the CPU modules that remain in short supply, thus limiting the expansion capabilities of a hardware based network.

Likewise whilst Helium IoT paved the way for decentralized networks to become a "thing" there is also the counter-argument now that actually it is incredibly difficult to build a hardware based network because of the growing disdain. Now obviously part of that is linked to failed projects like MXC, Planetwatch and WeatherXM as well as dubious projects like RevoFi.

That brings me on to our project- DeFli ( I am not going to extol the virtues of the project, all I am going to give is a very brief "blurb". We are building a decentralized network of ground stations for unmanned aircraft to communicate with (to satisfy new legislation) and which will form the basis of an advanced traffic management system.

A "ground station" can be built from any Helium Hotspot without affecting the performance, nor do we utilize the LoRa Concentrator (ADS-B is broadcast over the 1090MHz frequency). To achieve dual "mining" it is simply a case of running DeFli in a Docker Container (can be viewed on our Github) and adding a USB RTL-SDR receiver.

WARNING: As with anything cryptocurrency related, do your own research first before putting any of your own money in. This project could very well be a scam, or it could just be a project in the early stages of getting started.

DeFli Network Homepage

Tech Minds: Building A Low Cost RF Power Sensor

Over on the Tech Minds YouTube channel Matt has recently showed us his build of DL5NEG's super simple diode based RF power sensor. The device is designed to detect and measure RF power, using a DC voltage meter and a calibration curve which converts the voltage detected by the diode into dBm. The simple diode based design is remarkably accurate, and could be a useful tool for testing or calibrating SDRs.

Matt's first build uses a simple copper PCB board, and although it is low precision the results he achieved match up pretty nicely with the calibration curves. In Matt's second implementation he created a proper PCB design using KiCad and PCBWay. After soldering the components with hot air, he found that the results were just as good when he tested the power output of his AntSDR E200.

Matt intends to use this sensor along with a simple ADC connected to a Raspberry Pi to measure the power going into his QO-100 setup via a -40 dBm coupler.

This story was also shown Hackaday

A Low Cost High Performance RF Power Sensor

The RFNM: A Next Generation SDR with 10 MHz to 7200 MHz tuning range, 12-Bit ADCs and up to 612 MHz Bandwidth

The RFNM is an upcoming software defined radio that has some impressive high end specifications only seen in SDRs costing thousands, and at the same time the creator claims that it will be priced at a steal. While no pricing has been set, the creator noted in a Reddit post that pricing will be "closer to $500", bringing it's price similar to SDRs like the HackRF, bladeRF, LimeSDR, PlutoSDR.

The RFNM will have eight 12-bit ADCs on board, and provide up to 612 MHz of real time bandwidth for receiving. For transmitting it has two DACs, with up to 153 MHz of TX bandwidth. The tuning range will be from 10 MHz up to 7200 MHz. They note that their front end also has 13 preselection filters and six different LNAs and programmable attenuators.

Pushing 12-bit 612 MHz bandwidth of the device would be difficult, so to help with processing all that data, there will be an onboard VSPA DSP processor, as well as built in ARM CPU cores, and a 16 GFLOPS GPU. Connectivity will be either through USB 3.0, or Ethernet.

The main baseband chip on the SDR is the Layerscape® Access LA9310 chip sold by NXP which provides I/Q ADCs and DACs. Those signals are sent to the RFNM Daughterboard Interface, where they are upconverted to the frequency range of interest. This lets the end user choose a different daughterboard for different applications.

The Granita daughterboard has tuning capability from 600 MHz to 7200 MHz. To get frequencies down to 10 MHz the RFNM is making use of the RFFC2071A mixer. There will also be a cheaper 'lite' version that does not use a mixer, and hence only provides tuning from 600 MHz to 7200 MHz.

In addition, the website states that they are pursing a version of their board that will make use of the LimeSDR LMS7002 chip that will cover 10 MHz to 3500 MHz. They are also looking into boards that may break out more ADC lanes, an oscilloscope add-on, and breakout board.

You can join the RFNM email waiting list, and find more details about it at At the time of this post they state that the waiting list is "53% full". As of right now the project appears to have nothing concrete to show off, but the lead creator Davide Cavion was behind the FPV Blue HD Video system, so he appears to have the experience to take this project forward.

A render of the RFNM software defined radio board.