Tagged: Software-defined radio

Creating a Software Defined Radio from Tiny Tapeout Chips

Tiny Tapeout is a project that allows anyone to design and fabricate custom open ASIC silicon at a low cost by combining hundreds of projects from different people on the same chip. Each design on the the chip is freely available to use by others.

Over on Hackster.io, we've seen a post where Sylvain Munaut used two of these Tiny Tapeout chips to create a software defined radio.

On the Tiny Tapeout 6 chip, Sylvain discovered that Tiny Tapeout customer Carsten Wulff had implemented an 8-bit ADC on the chip. Then, on the Tiny Tapeout 7 chip, Sylvain found that Kolos Koblász had implemented an RF mixer. So, he decided to combine the two Tiny Tapeout chips together to build a software defined radio.

The entire build consists of the two Tiny Tapeout chips, a Glasgow Interface Explorer (USB interface), and a GNU Radio flowgraph to demodulate and display the signals received.

In his YouTube video, Sylvain demonstrates the software defined radio in action, showing that it has 2 MHz of bandwidth and is capable of receiving FM signals.

SDR with custom silicon ! Combining TinyTapeout projects.

Using an EFR32 IoT Microcontroller Transceiver as an SDR

Thank you to Joshua R. for writing in and sharing some links on how an EFR32 microcontroller can be used as a software-defined radio. The EFR32 is a microcontroller designed for IoT applications such as Zigbee, Z-Wave, Thread, Bluetooth. Of interest to us is that the EFR32 has a special mode that allows for the demodulator/modulators to be switched off and instead allowing for raw IQ data to be transferred from the chip.

An example of the EFR32 being used as an SDR has been provided by OH2EAT/tejeez and can be found in this write-up and in his 'geckokapula' GitHub repo. This MIT-licenced repo provides hardware schematics and software for creating a full handheld FM, AM, USB, LSB, and CW receiver with FM, CW, USB, and LSB transmit capabilities. It also supports a 12 kHz waterfall display. The tuning range is nearly 13.2 MHz to 2.9 GHz, but there are some gaps.

This Knowledge Article by Silicon Labs also explains the SDR mode of the EFR32.

This is an interesting low-cost chip, but the limiting factor appears to be the small bandwidth.

An EFR32 SDR by Tejeez/OH2EAT
An EFR32 SDR by Tejeez/OH2EAT

Setting up a Dual RX System with an SDR and Ham Radio Rig via an SDRSwitch

There are two common options when using an SDR together with a ham radio rig. You can either create an IF tap within your ham radio and connect the SDR to that, or connect the SDR directly to the antenna via a switch that switches the SDR out when transmitting.

Over on YouTube, Ham Radio DX has uploaded a video discussing the latter option and revealing its advantages. In the video, he mentions results by HB9VQQ that show that connecting an Airspy HF+ directly to an antenna via an SDR switch from SDRSwitch.com results in 60% more spots on WSPR, compared to using an IF tap from an FT450D ham radio rig.

He goes on to explain and demonstrate his setup and the recommended switch that he is using, which is the SDRSwitch by N2EME, available at SDRSwitch.com. He notes that this switch is recommended due to its very low insertion loss and high isolation specifications and compares it against an MFJ switch, which has some rather terrible specifications.

Add a SDR Receiver to ANY Ham Radio Rig!

SignalSDR Pro: An Upcoming SDR with 70 MHz to 6 GHz, 12 Bit ADC, 61.44 MHz Bandwidth and 2TX/2RX Channels

Over on CrowdSupply, a new software-defined radio called the 'SignalSDR Pro' made by Hong Kong company Signalens has recently been announced. The SignalSDR Pro is roughly the size of a credit card or Raspberry Pi and has a 70 MHz to 6 GHz tuning range, 12-bit ADC, 61.44 MHz of bandwidth, and 2RX/2TX channels.

The SDR is based on the AD9361 chipset, used by several other SDRs, including the PlutoSDR and Ettus USRP B210. It also comes with an AMD Zynq 7020 FPGA. Of note is a feature that allows the device to emulate a PlutoSDR and USRP B210, instantly making it compatible with software written specifically for those devices.

In the video below, creator KaiJern Lau introduces the SignalSDR Pro and explains the motivation behind creating it.

The project is currently in the pre-crowdfunding stage, and you can sign up for updates on its Crowd Supply page. 

The SignalSDR Pro
The SignalSDR Pro

BSidesPGH 2024 Talk: Introduction to Software Defined Radio For Offensive and Defensive Operations

Over on the YouTube channel "SecPGH" a talk by Grey Fox titled "Introduction to Software Defined Radio For Offensive and Defensive Operations" has been uploaded from the BSidesPGH 2024 conference. BSidesPGH 2024 was a security conference held in Pittsburgh, PA, USA on July 25.

The talks are generally about network security, however, Fox's talk is all about RF security topics and software defined radio. In the talk, he introduces SDR, and devices like the Flipper Zero and demonstrates various basic examples such as receiving FM from a handheld radio and ADS-B.

Next, he goes on to demonstrate security topics such as showing how to capture and analyze signals from a 433 MHz security alarm using an RTL-SDR and Flipper Zero, and how to jam frequencies and replay captured signals. Finally, he demonstrates WiFi cracking with the help of Kali Linux and Flipper Zero with WiFi dev board attached.

BSidesPGH 2024 Track 2 Grey Fox Introduction to Software Defined Radio For Offensive and Def

Pi Pico Rx: A Breadboard Software Defined Radio Based on the RP2040 Raspberry Pi Pico

Over on hackster.io we've seen a story about how maker Jon Dawson designed a self-contained software-defined radio based on the Raspberry Pi Pico that can receive 0 - 30 MHz, with up to 250 kHz of bandwidth. The Raspberry Pi Pico is a microcontroller board based on the Raspberry Pi Foundation's own RP2040 chip.

The Pi Pico Rx's front end consists of a Tayloe Quadrature Sampling Detector (QSD) mixer which makes use of the PIO (Programmable Input/Output) feature on the RP2040. The circuit also has an encoder knob for tuning and a small OLED screen.

Jon had originally created the Pi Pico Rx on a custom PCB, however, his latest work brings the cost down by showing that it can just as easily be implemented on a breadboard with through-hole components.

The full writeup can be found on Jon's blog "101 Things", as can the open source firmware. He has also uploaded a YouTube video explaining and demonstrating the project which we've embedded below.

Software Defined Radio with Pi-Pico

FOSDEM 2024 Call for Participation: Software Defined Radio & Amateur Radio Devroom

FOSDEM (Free and Open Source Developer’s Meeting) is a yearly conference that this year will take place in Brussels, Belgium on 3 - 4 February 2024. This conference will also feature a track on FOSS-powered radio, and there will be a combined Amateur Radio and SDR Devroom.

FOSDEM have issued a call for participation and have noted that slots are still open, so please submit any proposals for talks now if you are interested in presenting. The recommended topics include:

Topics discussed in the devroom include, but are not limited to:

  • SDR frameworks and the tools that make them useful
  • New SDR-based developments in ham radio modes
  • Cellular/telecom software
  • Amateur radio operator software tooling
  • Free / Open radio hardware
  • Wireless security research
  • Entertaining wireless hacks
  • SDR & ham radio in mass and higher education
  • Satellite, spacecraft and interplanetary communication

Software-Defined Radio is the technology of enabling radio signals to be processed and generated algorithmically, typically within general purpose processors, but also within FPGAs and GPUs; Free and Open Source (FOSS) Software Radio allows these algorithms to be inspectable and improvable. With the advent of ubiquitous IoT, sky-filling satellite megaconstellations and 5G/6G as standards designed with commercial Software Radios in mind, wireless is an exploding field of interest in the FOSS realm.

Ham Radio, also known as amateur radio, is more than just a hobby orbiting the usage of radio communication – it’s a passion that merges the realms of electronics, human interaction, and communication. At its core, ham radio is about establishing connections: with people, with technology, and with the world at large. It is a free and open community effort at heart!

RFNM Updates: Motherboard Prototypes Manufactured

Back in April we posted about the RFNM, an upcoming software defined radio project which will have eight 12-bit ADCs, up to 612 MHz real time bandwidth, and two DACs for transmitting with up to 153 MHz bandwidth. The standard board will support tuning from 600 - 7200 MHz, with tuning expanded down to 10 MHz via an RFFC2071A mixer.

Recently they've updated their blog and show that they have successfully manufactured the first prototype of the RFNM motherboard. The motherboard is the board containing the LA9310 RF and computing chips, and then they intend on having various daughterboards for tuners that will expand the tuning range and performance.

They also updated their pricing, noting that they have upgraded a few specifications. The motherboard is set to be priced at $299. It will be available for preorder in August, with an expected October delivery date.

The RFNM Motherboard