Over on YouTube user TheGazLab has uploaded a video that reviews the Airspy HF+, and also shows how to use the HF+ with SDR# and WSJT-X in order to create a FT8 monitor. The Airspy HF+ is high dynamic range HF/VHF receiver designed for DXing.
In the video TheGazLab demonstrates to us the decoding in real time, and explains the CAT control SDR# plugin that he's using. The CAT control plugin when combined with a virtual serial port driver allows the WSJT-X program to automatically tune SDR# to the FT8 frequency selected in WSJT-X.
Later in the video he also discusses the SpyServer network which allows SDR# users to connect to remote public Airspy and RTL-SDR units over the internet. He demonstrates connecting to a public server in the UK, and decoding FT8 via the remote server. The video also shows the new SpyServer interface by @zakhttp which nicely lays out the world SpyServer network on a map, making it easy to choose a desired location to listen to.
Airspy HFPlus, SDR# and WSJT-X with full CAT control decoding FT-8
Vasilli has recently released the SDR# TETRA plugin on his website RTL-SDR.RU (note that the site is in Russian, but can be translated with the Google Translate option in the top right of the page). Previously it was only available via ever changing forum links, so it's good to see that it has a permanent home now for the latest version. This plugin allows you to listen to TETRA digital voice via SDR#, without needing to set up any complicated GNU Radio based receivers which were necessary in the past.
The features include (note Translated from Russian):
Receiving a signal from the BS band 25kHz and modulation Pi / 4-DQPSK;
Automatic adjustment of the reception frequency;
Displays information about the BS;
Displays ISSI, GSSI subscribers in the channels (for open channels only);
Displays a service exchange network (for open channels only);
It allows you to listen to the channels in manual or automatic mode selection (only open channels);
It allows to filter and distribute the listening priority specified for groups (GSSI);
It displays a message with the location (just a short message format)
The current features not yet implemented are:
And listen to correctly display any encoded information in a network;
Display SDS type 4 (short messages);
Record audio from the channels (menu added, but does not work);
We also note that as discussed in a previous post there is a companion program for this plugin called TETRA Trunk Tracker.
Back in August Maxim who runs his small company "ExpElectroLab" wrote in and shared with us news of his upcoming product called "SDR-Remote" which is a physical tuning knob and control panel for SDR#.
Recently the product was released for sale on his shop, and costs $57.50 USD + shipping. The vk.com store is for Russian customers only, but you contact him at [email protected] if you are non-Russian and are interested in his products. The features of the SDR-Remote are pasted below:
The heart is ARDUINO NANO V3.0, buttons, encoder and software.
tuning the frequency of reception with frequency of 1 kHz, 100 kHz, 1 MHz (additionally 50 Hz)
Maxim hand builds these in his home country of Russia, and has noted that since the case is 3D printed he can only create a few per week at the moment. The knob interfaces with SDR# via an Arduino driver and SDR# plugin which can be downloaded.
Over on YouTube a Russian reviewer has uploaded a video showing SDR-Remote v2.1 in action. The video is narrated in Russian, but YouTube auto-captions combined with auto-translate does a decent job.
The idea behind the article is to introduce people to SDR from a shortwave listening point of view, so high performance HF SDRs like the Airspy HF+, Elad FDM-S2 and WinRadio Excalibur are discussed. Thomas notes that these SDRs can perform as well as traditional DX-grade receivers that can cost two to three times more. He also explains what advantages SDR's bring to the shortwave radio listening hobby. This may be a good article to show those still using older hardware radios that haven't yet converted to the SDR world.
The article is currently part one of a three part series, with parts two and three to be released in October and November.
As expected, the AIR-T is not a cheap with it coming in at US$5,699, and this is with a 10% discount off the MSRP. However, the AIR-T is likely to be more of interest to high end industry and university researchers who have research money to spend. Also, compared to Ettus E310/N310 and LimeNET Mini SDRs which have built in non-GPU based computing platforms and similar SDR performance, the AIR-T could be seen as reasonably priced assuming that the software and drivers for it are decent. In the future we expect to see the price of similar SDR-AI development boards eventually reduce down to hobbyist level prices.
The basic idea behind the AIR-T is to combine a 2x2 MIMO SDR transceiver with a NVIDIA Jetson TX2 GPU that can be used to run artificial intelligence (AI) software fast. They will include software that will allow GNU Radio and Python code to be easily ported to the GPU architecture.
Why build tomorrow’s tech with yesterday’s signal processing tools? The Artificial Intelligence Radio - Transceiver (AIR-T) is a fully integrated, single-board, artificial intelligence equipped, software defined radio platform with continuous frequency coverage from 300 MHz to 6 GHz. Designed for new engineers with little wireless experience to advanced engineers and researchers who develop low-cost AI, deep learning, and high-performance wireless systems, AIR-T combines the AD9371 RFIC transceiver providing up to 2 x 2 MIMO of 100 MHz of receiving bandwidth, 100 MHz of transmitting bandwidth in an open and reprogrammable Xilinx 7 FPGA, with fast USB 3.0 connectivity.
The AIR-T has custom and open Ubuntu software and custom FPGA blocks interfacing with GNU Radio, allowing you to immediately begin developing without having to make changes to existing code. With 256 NVIDIA cores, you can develop and deploy your AI application on hardware without having to code CUDA or VHDL. Freed from the limited compute power of a single CPU, with AIR-T, you can get right to work pushing your telecom, defense, or wireless systems to the limit of what’s possible.
The SDR transceiver chip used is a Analog Devices 9371. This is a high end chip that can be found on high end SDR hardware like USRPs. If you're interested we had a post about decapping the AD9361 recently, which is a similar chip. It provides 2x2 MIMO channels, with up to 100 MHz RX bandwidth and 250 MHz TX bandwidth. The NVDIA Jetson TX2 is a GPU 'supercomputer' module specifically designed for AI processing. Many AI/machine learning algorithms, such as neural networks and deep learning run significantly faster on GPU type processors when compared to more general CPU's.
These are not cheap chips with the AD9371 coming in at over US$250 each, and the Jetson TX2 coming in at US $467. Although we don't know what sort of bulk discounts the AIR-T manufactures could get. But it will be certain that the AIR-T will not be for the budget minded.
The board is still awaiting release of it's crowdfunding round, and you can sign up to be notified of when the project launches on their Crowd Supply page.
The melding of AI and the RF spectrum will be common in the future, and a development board like this is one of the first steps. Some of the interesting use cases that they present are pasted below:
From Wi-Fi to OpenBTS, use deep learning to maximize these applications. By pairing a GPU directly with an RF front-end it eliminates the need of having to purchase an additional computer or server for processing. Just power the AIR-T on and plug in a keyboard, mouse, and monitor and get started. Use GNURadio blocks to quickly develop and deploy your current or new wireless system. For those who need more control, talk directly with the drivers using Python or C+. And for those superusers out there, the AIR-T is an open-platform, so you can program the FPGA and GPU directly.
Communicating past Pluto is hard. With the power of a single-board SDR with an embedded GPU, the AIR-T can certainly prove out concepts before you launch them into space. Reduce development time and costs by adding deep learning to your satellite communication system.
There is an endless number of terrestrial communication systems with more being developed every day. As the spectral density becomes more congested, AI will be needed to maximize these resources. The AIR-T is well-positioned to easily and quickly help you prototype and deploy your wireless system.
The AIR-T allows you to demodulate a signal and apply deep learning to the image, video, or audio data in one integrated platform. For example, directly receiving a signal that contains audio and peforming speech recognition previously required multiple devices. The AIR-T integrates this into one easy to use package. Whatever your application is, from speech recognition to digital signal processing, the integrated NVIDIA GPU will jump start your applications.
For many communications and radar applications once the signal is collected it must be sent to an off-board computer for additional processing and storage. This consumes valuable time. The AIR-T eliminates this. From its inception, it was designed to process signals in real-time and eliminate unnecessary latency.
Several new software defined radio talks have been released on YouTube this week from the big European 2018 Friedrichshafen Ham Radio Convention which just finished this month. The full list of 14 new videos can be found on the Software Defined Radio Academy YouTube channel. Below are two of our favorites:
The OVI40 / UHSDR Project, Developing An Open Standalone SDR
OVI40 is an Open Source standalone homewbrew SDR TRX project (VLF to 2m), developed with the aim of being modular and future-proof. The talk describes the hardware and the UHSDR software including a discussion on the evolution from the "single-system" software used for the well-known mcHF (initially written by Chris, M0NKA and Clint KA7OEI) to the multi-SDR approach in the UHSDR software project.
DF8OE, DB4PLE, DL2FW, DD4WH: The OVI40 / UHSDR Project - Part 1 and 2
András Retzler, HA7ILM: Let's code a simple receiver in C
For using SDR in amateur radio applications, it is easier to use existing receiver software, or create GNU Radio flowgraphs with pre-build blocks. On the contrary, in the do-it-yourself spirit of amateur radio, this talk will guide you through the steps of implementing a simple AM/FM/SSB receiver from scratch, in plan old C, in order to get a deeper understanding of what happens actually under the hood in popular SDR software. The talk builds on the author's learning experience of creating the open source CSDR command line tool, which is used for DSP in the OpneWebRX web based SDR receiver.
András Retzler, HA7ILM: Let's code a simple receiver in C
Analog Devices has recently released a new text book for free called "Software-Defined Radio for Engineers, 2018". This is an advanced university level text book that covers communication systems theory as well as software defined radio theory and practice. The book uses the PlutoSDR as reference hardware and for practical examples. The PlutoSDR is Analog Devices $150 RX/TX capable SDR that was released about a year ago.
The objective of this book is to provide a hands-on learning experience using Software Defined Radio for engineering students and industry practitioners who are interested in mastering the design, implementation, and experimentation of communication systems. This book provides a fresh perspective on understanding and creating new communication systems from scratch. Communication system engineers need to understand the impact of the hardware on the performance of the communication algorithms being used and how well the overall system operates in terms of successfully recovering the intercepted signal.
This book is written for both industry practitioners who are seeking to enhance their skill set by learning about the design and implementation of communication systems using SDR technology, as well as both undergraduate and graduate students who would like to learn about and master communication systems technology in order to become the next generation of industry practitioners and academic researchers. The book contains theoretical explanations about the various elements forming a communication system, practical hands-on examples and lessons that help synthesize these concepts, and a wealth of important facts and details to take into consideration when building a real-world communication system.
The companion site for the book which contains links to complimentary online lectures, slides, and example MATLAB code can be found at https://sdrforengineers.github.io. MATLAB is a very powerful programming language and toolset used by scientists and engineers. MATLAB is not a cheap tool, but there is a home user licence available for a more reasonable price. To do some of the exercises in the book you'll probably at least require the core MATLAB plus the Communications System Toolkit which is an extra add on.