Category: Applications

Building a Drone Tracking Radar with the ADALM-PHASER and PlutoSDR

The ADALM-PHASER is a kit designed to provide experience with phased array beamforming and radar concepts. The kit consists of a PlutoSDR, mixers, LO synthesizer, ADAR1000 beamformer chip, LNAs and array of patch antennas. It operates between 10-11 GHz, has 500 MHz BW FMCW chirps, and has 8 receive channels and 2 transmit channels. It is an open source kit that costs US$2800, and it is produced and available from Analog Devices. Currently the kit appears to not be in stock, but they note that they are working on getting more stock in soon.

The ADALM-PHASER a phased array kit for implementing radar and other phased array experiments.
The ADALM-PHASER a phased array kit for implementing radar and other phased array experiments.

Over on YouTube, Jon Kraft who appears to be affiliated with Analog Devices, is working on a series of videos that will ultimately result in a drone tracking radar being built with the ADALM-PHASER. Currently two videos have been released.

The first is an overview of radar concepts, giving an explanation of pulsed vs CW radar, and the various hardware options we have to implement low cost versions of these methods.

The second video covers more radar concepts like range resolution and shows us how to build a CW radar with the ADALM-PHASER system.

The three remaining videos are yet to be released, so keep an eye on his channel for updates.

Build Your Own Drone Tracking Radar: Part 1

Build Your Own Drone Tracking Radar: Part 2 CW Radar

Tech Minds: Video on DJI Drone Detection on the AntSDR E200

Just recently we posted about the release of some firmware for the AntSDR E200 which allows it to decode DJI DroneID. DroneID is a protocol designed to transmit the position of the drone and operator to authorized entities such as law enforcements and operators of critical infrastructure.

In his latest video Matt from the Tech Minds YouTube channel shows this firmware in action. In the video he first shows how to install the firmware, and how to connect to its serial output. He goes on to test it with his DJI Mini 4 Pro and show some live DroneID frames being decoded.

DJI Drone Hacking Using Software Defined Radio ANTSDR E200

DJI DroneID Detection Running on the AntSDR E200 CPU

DJI is a major manufacturer of consumer drones and their drones implement an RF protocol called DroneID which is designed to transmit the position of the drone and operator to authorized entities such as law enforcements and operators of critical infrastructure. 

Recently the AntSDR team have managed to get DJI DroneID decoding working on the AntSDR's onboard ARM processor. The decoding software runs on board the AntSDR E200 and outputs decoded data via the serial or network port. The AntSDR E200 is an SDR that is based on the AD9361 chip and has a 70 MHz to 6 GHz tuning range, 56 MHz of bandwidth and 12-bit ADC. It has 2x2 full duplex TX/RX channels and has an onboard FPGA with ARM CPU core.

They make use of existing code on GitHub from  https://github.com/proto17/dji_droneid and https://github.com/RUB-SysSec/DroneSecurity, both of which implement reverse engineered decoders for DroneID.

The update from AntSDR shows how to install the firmware onto the device and get it up an running. They note that drones that use Occusync 2 or 3 like the Mini2 or Mini3Pro work best, because other models may be encrypted or have a slightly different protocol which doesn't work with these decoders.

Aaron, creator of DragonOS has also uploaded a video showing the decoder in action.

DragonOS FocalX Decoding DJI DroneID w/ AntSDR E200 (MicroPhase)

Modified RTL-SDR Source for SDR++ with Manual Controls for R820T/2/R828D Tuners and Harmonic Reception

Over on GitHub user Sultan-papagani has just released a modified RTL-SDR source for SDR++ that enables full manual control of the gain stages, filters and other features on R820T/2/R828D tuner based RTL-SDRs. This includes the Blog V3 and Blog V4. In the standard drivers many of these these features are automatically controlled.

Tweaking the individual LNA, Mixer and VGA gain stages manually can help you to maximize SNR, while adjusting the filters can help block out of band interference.

The modified source also enables the 'Hamonic reception' enhancement from the librtlsdr fork of rtl-sdr, which allows you to tune up to 6 GHz via harmonic mixing. Note that tuning above the standard maximum of 1.766 GHz will most likely require strong band pass filtering and an external LNA as the harmonic mode results in a lot of imaging and weak signals. 

A new RTL-SDR Source for SDR++ with Manual Gain/Filter and Harmonic Mixing Controls
A new RTL-SDR Source for SDR++ with Manual Gain/Filter and Harmonic Mixing Controls

A WSPR Monitor Running on an old Android TV Box with OpenWebRX and RTL-SDR

Thank you to Joseph IT9YBG for writing in and sharing with us his experience in getting Armbian and OpenWebRX running with an RTl-SDR V3 smoothly on an old A95X Android TV Box. These TV Boxes have an AMlogic S805 chip and Joseph writes that he is quite impressed by the performance of the chip.

To install the Armbian Linux operating system Joseph used the instructions from i12bretro and installed OpenWebRX after. Then together with his RTL-SDR Blog V3 dongle he turned the device into a cheap dedicated WSPR (Weak Signal Propagation Reporter) monitor allowing him to free up his Raspberry Pi 3 which was used for the task previously.

IT9YBG's Android TV Box converted into a WSPR monitor with an RTL-SDR Blog V3 and OpenWebRX
IT9YBG's Android TV Box converted into a WSPR monitor with an RTL-SDR Blog V3 and OpenWebRX

Tech Minds: Making your own SDR Software With GNU Radio Companion

In his latest video out on YouTube, Matt from the Tech Minds channel gives us an overview of GNU Radio, and shows a few examples of how it can be used to receive, transmit and decode digital data.

GNU Radio is a popular open source DSP framework for software defined radios. With it you can graphically implement any sort of digital signal processing chain that you like, which can be used for decoding/encoding and demodulating/modulating signals.

GNU Radio can be extremely complex and powerful, but in the video Matt shows some simple starter example flowgraphs like an LSB demodulator, and a simple wav file source transmitter for the HackRF. 

How To Make Your Own SDR Software With GNU Radio Companion

Downloading Stored Images and Data from the NOAA Weather Satellite GAC Broadcast

With polar orbiting weather satellite reception we as amateur ground station operators with SDR receivers typically download images via "Direct Broadcast", which provides imagery of what the satellite is currently seeing live. However, the main way satellites such as the NOAA POES (NOAA 15, 18 & 19) satellites downlink is via "Global Area Coverage" (GAC) broadcast which provides the full stored imagery data of the entire global pass. However, GAC is only broadcast in locations where the satellite operator operates ground stations.

Over on YouTube dereksgc has uploaded a video showing how to receive GAC data from the NOAA POES satellites. He notes that GAC is now broadcast at 2247.5 MHz in the S-band, and the ground station it now downlinks to is likely in Svalbard, rather than in the USA. This means that amateur satellite stations close to the North Pole can receive the GAC signal, including dereksgc's station which (we believe) is in the Czech Republic.

Dereksgc uses a large 250cm offset dish with S-band feed connecting to a HackRF. In the video he demonstrates him receiving the signal, and then decoding it using SatDump. Finally he shows all the images from various locations around the earth that he was able to receive from one satellite pass.

DATV-Red: An Interface for Controlling PlutoSDR in Node-RED

Thank you to Ohan Smit (ZS1SCI) for submitting news that he has published his software called DATV-Red over on GitHub. The software is open source and is design to be an interface for controlling a PlutoSDR in Node-RED.

The PlutoSDR is a low cost RX/TX capable SDR with up to 56 MHz of bandwidth and 70 MHz to 6 GHz frequency range (with mods). Node-RED is a visual programming tool for creating JavaScript functions.

Ohan writes:

I've built an interface for controlling the plutosdr in Node-red.

It works on the latest PlutoDVB firmware.

It is cross platform since it is web based.

Currently the scope is focussed on QO-100 use, yet with the latest addition of the RX spectrum from the Pluto's onboard web socket, the focus would shift to a general spectrum analysis and RF operation with special operational DATV features

[It is] a work in progress.

DATV-Red: An interface for controlling the PlutoSDR in Node-RED