Category: Other

YouTube GNU Radio Tutorials for Windows 10

Thank you to YouTuber M Khanfar for submitting news about his various Windows GNU Radio tutorials that he has been uploading to YouTube. So far he's uploaded tutorials on creating an FM Receiver, Air Band Receiver, AM/NFM Receiver, NFM Receiver with Squelch and Recorder and Spectrum Analyzer with GNU Radio on Windows 10. The tutorials are straight to the point and designed to be followed along with the video. The full list of videos can be found on his YouTube channel, and we have embedded one below.

Build NFM Reciver with Squelch and Recorder Activity GNU RADIO Win10

Radenso Theia: An SDR Based Police Radar Detector

Radenso is a company that sells radar detectors. These are used to help motorists avoid speeding fines from Police using radar speed detectors in their cruisers. Their latest upcoming product is called the "Radenso Theia" and is a software defined radio based solution.

In one of their latest YouTube videos they explain how SDR is used in the Theia, noting that the SDR ADC chip they are using is an AD9248. The use of an SDR allows them to more easily apply advanced digital signal processing algorithms to the radar detection task. In particular they note that they can now apply deep learning artificial intelligence filtering which helps to classify different radar gun FFT signatures and avoid false positives from other radar sources such as automatic doors.

While the Theia is designed to be a radar detector, they note that the device could also be used by hardware hackers as a standalone software defined radio. They have thought about this use case and have added a separate uFL connector that can be enabled by soldering a zero ohm connector, and this allows users to connect any antenna to it.

What is a software defined radio and why does it matter for Radenso Theia?

ARM Radio Code Ported to Free Toolchain

Several years ago in 2015 we posted about the "ARM Radio" by Alberto I2PHD which is a minimalist SDR implementation based on the ARM processor on the STM32F429 discovery board. It was implemented with nothing more than a basic low pass front end, a reconstruction filter for the audio output and some DSP code. With it's low cost ADC it's only able to tune from 8 kHz to 900 kHz, but this is enough to get broadcast AM signals and NDBs. While it may not have the best specs, it's an excellent learning project for SDR DSP and microcontroller programming, and the code is completely open source, although a non-free toolchain is required.

Recently Alberto Garlassi wrote in and wanted to share a re-implementation of the code on a free toolchain. He writes:

Unfortunately the author used the Keil MDK toolchain, this means that it is not possible to change the code without paying for a license. The free version is limited to 32K and this is not enough.

I ported it to the free (don't know how much, certainly GCC + Eclipse) System Workbench, now it is easy for everybody to start where I2PHD left.

I did this several years ago and in the meantime ST and ARM changed many things in their tools and libraries, but it still works ok, I checked.

The complete project is on Github, it should be a matter of downloading the IDE, the libraries and press the debug icon. I'm in touch with Alberto Di Bene I2PHD, he has no objections and told me he's happy about this.

TechMinds: Hands on with the Elektor SDR Arduino Shield Learning Kit

The Elektor SDR Hands-On-Kit is a low cost (€49.46) SDR learning package that makes use of the Elektor SDR Arduino shield which turns an Arduino microcontroller board into a 150 kHz to 30 MHz capable SDR receiver. It also comes with a book that teaches several basic SDR concepts.

Over on YouTube TechMinds has recently uploaded a video where he unboxes, constructs, and tests the kit using the free G8JCFSDR SDR software. TechMinds also notes that this SDR Shield can also transmit with 10mW of power, and that there is a tutorial included in the book that shows how to use the shield as a simple WSPR transmitter.

Elektor SDRShield - Hands-on Software Defined Radio Kit

Building a 1-Bit Oversampling SDR with not much more than a low cost FPGA

Thank you to Alberto Garlassi for submitting information about his super low parts home made FPGA software defined radio which is capable of medium wave and shortwave AM reception. What makes this design interesting is that is is created with nothing more than 3 resistors, 1 capacitor, and a low cost 30€ Lattice MachXO2 FPGA dev board.

The design makes use of the FPGA's LVDS buffer input to implement a direct sampling 1-bit ADC to which a wire antenna is directly connected to. This 1-bit resolution is increased by using an SDR trick that involves superimposing random RF noise onto the desired signal, and oversampling at 80 MHz then decimating down to a 6 kHz bandwidth. This results in an effective ADC resolution of 6-bits, from 1-bit hardware.

Synthesized on the FPGA is the ADC, Mixer, two CIC filters, an AM demodulator and a PWM circuit for audio output. The synthesis allows for medium wave and shortwave AM reception where the frequency can be tuned via PC control.

The FPGA Verilog synthesis files are available on the projects' GitHub page, and a more in depth explanation of the SDRs operation is available on its hackaday.io page. Alberto has also created a short demonstration video which is shown below.

FPGA + 3 R + 1 C = Medium and Long Wave SDR Receiver.

OpenAstroTracker: 3D Printed DSLR Tracking Mount may be useful for Antennas Too

OpenAstroTracker is a recently published open hardware 3D printed tracking mount designed to move DSLR cameras for astrophotography. The mount supports heavy long lenses, so we think that this mount could also have the ability to move long directional antennas for satellite tracking. It could also be interesting to modify it for automatic aircraft photography, similar to what we've seen in this previous post where a Raspberry Pi camera on a pan-tilt mount was used with ADS-B data from an RTL-SDR to track aircraft in the sky with the camera.

The 3D printer files are available on Thingiverse, and the mechanical and electronics build guide, and Arduino code is available on GitHub. The build seems to be quite a bit easier compared to a SatNOGS rotator which is another 3D printed open hardware rotator, but it is yet to be seen what sort of antenna sizes it could rotate.

OpenAstroTracker: Could be modified for satellite tracking.
OpenAstroTracker: Could be modified for satellite tracking.

Michael Ossmann & Kate Temkin Present Software Defined Everything with GreatFET One

At the Hackaday Supercon Michael Ossmann & Kate Temkin presented a talk called "Software-Defined Everything" where they demonstrated some applications of the "GreatFET One" interface board. Michael Ossmann is best known for creating the HackRF software defined radio which is a highly versatile and low cost open hardware/software SDR transceiver. His company Great Scott Gadgets also employs Kate Temkin who is the lead software developer who worked on their latest product called the GreatFET One.

The GreatFET One is a multi-purpose digital interface board that plugs into a PC via USB. It contains multiple digital IO pins, supports SPI, I2C, UART and JTAG serial protocols, can do logic analysis, and also has a built in ADC and DAC.

In the talk Michael and Kate show how a simple light sensor can be plugged into the GreatFET's ADC, allowing the sensor's data to be digitized and processed in GNU Radio. This results in a software defined light sensor. By analyzing the light data in the frequency domain via an FFT graph they're able to determine the refresh rate of the ceiling lights.

Later they also show how GreatFET can be combined with i2C sensors and GNU Radio to do creative things like use an accelerometer as a microphone for a guitar pickup, with audio effects like guitar clipping controlled by GNU Radio blocks.

Michael Ossmann & Kate Temkin - Software-Defined Everything

Gaining Access to Windows on the Flex 6500 SDR Transceiver and Installing Other Programs

The Flex 6500 is a now discontinued (only refurb units available for US$2,600) transceiver SDR made for amateur radio use. Together with the optional Maestro control panel, it forms a fully standalone SDR based transceiver, with built in SDR software available on the Maestro's LCD screen. The system runs embedded Windows and is locked down to prevent the user from getting outside the Flex radio software.

However, a Norwegian University radio club found the Flex radio to be very inflexible as they could not connect the radio to their Universities WiFi system, which requires users to authenticate first via a web browser. What should be a simple task on any Windows system was unfortunately not supported by the radio software, and Flex radio themselves were unable to help.

Fortunately the students were able to hack the Windows filesystem via a backdoor found in the built in software, allowing them full access to the Windows desktop. The hack is fairly simple, consisting of gaining access to Notepad and thus the filesystem and command prompt via a "view source" right click menu on the web login interface. Once hacked, the students were able to install custom software like the N1MM+ contest logger, and WSJT-X for WSPR decoding. They were also able to connect a Bluetooth keyboard and mouse which was not supported by default.

[Also seen on Hackaday]

FlexRadio 6500 hacked to gain access to Windows.
FlexRadio 6500 hacked to gain access to Windows.