In his post Lukas describes how he designed the PCB with Altium Designer, routing the traces carefully to ensure the shortest path was used, and to ensure impedance matching was correct. Then after producing the PCB’s with OSH park he writes how he assembled the board by carefully placing the components down by hand and using his reflow oven. This was no easy task due to the manual nature of the operation and the high possibility for undetectable solder problems to arise. Despite the difficulties he found that the SDR powered up as expected.
His next steps were to start work on the FPGA controller design, however he discovered that he had failed to properly route some clock pins on the FPGA. On his third revision of the PCB he was able to fix this. Finally he was able to program the FPGA and get his SDR to work.
Designing an SDR from scratch is no easy task, especially if you have little design experience like Lukas did. However, in the end despite some mistakes he was able to build a working SDR that interfaces with GNU Radio.
Back in November 2015 we posted about the ARM Radio, a minimalist direct sampling software defined radio that runs almost entirely on an ARM processor on a STM32F429 discovery board. It can tune from about 8 kHz up to 900 kHz, which covers the VLF, LF and some of the MF bands.
Now over on YouTube amateur radio hobbyist W9RAN has uploaded a video where he demonstrates an ARM Radio that he built. He shows the radio in operation with it clearly receiving some NDB’s and some AM broadcast stations.
To make it actually work as an SDR he also wrote some code to utilize the development board’s ARM processor which processes the ADC input into a radio signal, demodulates it and then turns it into audio via the boards DAC and speaker. The radio can tune from 8 kHz up to about 900 kHz.
The only real extra hardware in Alberto’s system is a low pass filter for anti-aliasing and impedance transformation, and a reconstruction filter to get sound to the speakers from the DAC. He also used the boards LCD screen to implement a full GUI tuning system.
The attack is pretty simple in theory. It works by using a software defined radio to transmit a high power amplitude modulated CW signal that will be picked up by the microphone’s cable which acts like an antenna. The AM CW signal is modulated in such a way that the built in low pass filter in the microphone works as a demodulator and turns the signal into an audio voice command.
In their experiments they were able to use a USRP SDR, amplifier and directional Yagi antenna to cause a smartphone to load up their webpage. The same attack could probably be performed with a cheaper HackRF SDR.
A talk by the researchers was uploaded to Google earlier this month and is shown below.
Balint Seeber is a researcher at Ettus, designers of the USRP line of software defined radios. Every so often he gives an interesting conference talk about his latest projects. This time he’s given a talk at Ruxmon Sydney in April of this year and it has just been uploaded to YouTube.
In the talk Balint overviews the projects that he’s working on or completed. His topics include:
His work with creating his own battery powered GSM base station including a live demo where members from the audience connect to and call him via the base station.
His work with FPV drones and creating an SDR based FPV digital video system.
Hacking restaurant pagers.
Attempting to communicate with and revive the ISEE-3 spacecraft using the large radio dish at Arecibo.
Gathering actual RADAR data from listening to a real airport active RADAR system and plotting the returns on a map.
Investigating RFID tags and attempting to unlock his car via an SDR.
Back in November, 2014 we posted about the PortableSDR, a 0 – 35 MHz portable software defined radio transceiver that was the third place winner in the Hackaday Prize competition. The PortableSDR project is gaining traction and now has a Kickstarter campaign. They write:
The Portable Software Defined Radio, or PSDR, is an Open Source, Fully stand-alone HF/Shortwave Software Defined Transceiver. It includes a Vector Network Analyzer and Antenna Analyzer as well as GPS. It’s built for rugged portable use. It is designed to be a flexible platform for development, a learning aid, and and a useful instrument for electronics enthusiasts.
Coverage from 0 to 35MHz
Waterfall display that lets you see radio signals
Receives AM, USB (Upper Side Band), LSB (Lower Side Band), and Morse code (CW)
Modulates USB and LSB signals
Variable bandpass filter
The campaign hopes to raise $60,000 USD to aid in the development of the hardware and software and with the manufacturing process. The kickstarter is offering kits at various stages of completion from $250 to $475 and a fully assembled kit at $499. They note that the current PSDR2 that you will receive from the Kickstarter is still a development version, not the final product. The PSDR2 is missing some key features that will be in the final version like filters and output amplifiers.
The popular Hackaday blog is having a contest where contestants submit homemade prototypes of opensource devices they have created. The prize is a trip to space and the winner will be awarded to the best example of an open, connected device. The finalists were recently announced and a device called the PortableSDR is one of them.
The PortableSDR is a portable rugged standalone software defined radio transceiver with a 0 to 30 MHz tuning range (also 144 MHz). A standalone SDR means that no computer is required to use the radio, and can work in a similar way to a standard handheld hardware radio. Its advantages come from its SDR design, which allow it to have a wide tuning range, be able to easily decode most protocols and to also work as an antenna analyzer or vector network analyzer.
Some people have been calling this radio a Baofeng UV-5R killer, which is very high praise as the Baofeng is one of the most popular low cost hardware radios out there.