Programme

10:00 - 10:15 Prof. Dr. Michael Hartje DK5HH, Markus Heller, M.A., DL8RDS: Welcome and Introduction

10:15 - 10:30 Andreas Spiess HB9BLA: Keynote

10:30 - 11:00 Lucas Speckbacher OE2LSP: SDR-Buffer - Time travel on ham bands

SDR receivers are capable of receiving entire ham radio bands simultaneously. Normally this is only possible in near real time, the goal is to make the data available over a longer period and to more than one user, the SDR-Buffer was developed, to allow listening to QSOs even days or weeks later. At the same time, the data has to be presented in a way that makes it easy to find the desired signals.

After initial tests on VHF/UHF the system was extended to cover the shortwave ham radio bands. It now covers almost all ham radio bands below 1 GHz and has been in operation for nearly two years. This publicly available and open source system is used by everyday hams and SWLs as well as the intruder monitoring community across the borders.

This talk will show in detail how the system is works, despite being designed on a fairly small budget, and some of the challenges along the way.

11:00 - 11:30 Rob Robinett AI6VN: Creating a low cost high performance FST4W/WSPR beacon site using the RFzero or QPR Labs QDX

In his presentation Gwynn Griffiths and Nigel Squibb have shown how the spectral spreading information logged by the WSJT-x FST4W decoder can offer hams and researchers new insights in to HF propagation. While there are dozens of wsprdaemon KiwiSDR FST4W receive sites around the world already decoding and logging FST4W spots on all of the HF bands, there are only a few sites transmitting those signals. The frequency accuracy and stability required by this use of FST4W means that existing low cost WSPR beacons like the widely deployed QRP Labs U3S and Zacktek cannot be easily converted to FST4W transmitters, and there are only a few very costly ham transceivers which come with external clock input ports. However QRP Labs has recently introduced the US $70 QDX digital mode transceiver kit which, when paired with a Raspberry Pi running WSJT-x and a low cost GPSDO, creates a 80-20M or 20-10M transmitter which meets the requirements of this application. It is to be hoped that the easy installation and low cost of such a system will encourage many more hams to deploy such beacons worldwide and thus expand propagation studies beyond North America and Europe.

11:30 - 12:00 Gwyn Griffiths G3ZIL, Nigel Squibb G4HZX: Propagation path analysis on the HF bands using Software Defined Radio and FST4W

Software defined radios (SDRs) such as the KiwiSDR receiver, the RFZero transmitter, and the QRP Labs QDX digital transceiver can provide the hardware components for an innovative application - a propagation path analyzer. The main software for the system is FST4W, a recently added protocol within the widely distributed WSJT-X package. Using straightforward time series and scatterplot data analytics of spectral spread and signal level or SNR different propagation modes can be identified. These include the obvious daytime one- and multiple-hop magneto-ionic refraction in the F2 layer of the ionosphere. The SDR and FST4W combination also gives a 'fingerprint' for less commonly known modes including two-hop side scatter that can dominate at frequencies above the maximum usable frequency for a band and time of day. Over long paths ionosphere-to-ionosphere modes can be identified, including chordal hop and perhaps ducting. The changes, or evolution, over a day in the propagation modes between pairs of stations can also be studied. Using a variety of paths originating in Europe and terminating in Europe, in the Arctic across the Auroral Oval, across the Atlantic, and to Australasia we show how applying the combination of SDRs and FST4W provides insights into propagation paths that cannot be obtained simply from SNR.

12:00 - 12:30 Lunch Break

12:30 - 13:00 Sylvain Azarian F4GKR: Ulrich L Rohde Award Ceremony

13:00 - 13:30 Laurence Barker G8NJJ: Completion of the Saturn SDR

This paper presents completion of the Saturn SDR. We had presented a first prototype at SDRA 2022. We describe the work that has been required to develop and debug the Xilinx FPGA and the SDR server application that executes on a raspberry pi processor to achieve a complete working HF software defined radio.

To optimise the DSP within the FPGA we describe a combination of logic simulation followed by GNU Octave scripts to analyse the data collected from the simulation. We present results showing the combination that could not be achieved using Vivado or Octave alone. Vivado has provided bit-true results; Octave has enabled graphical presentation and frequency domain analysis.

We present the completed radio and show it working with an established remote PC client application (Thetis) and an established local client application (Pihpsdr). Finally we present concepts for future work that is enabled by the combination of FPGA and local ARM processor.

13:30 - 14:00 Daniel Estévez EA4GPZ: Maia SDR: An open-source FPGA-based SDR project focusing on the ADALM Pluto

Maia SDR is a new open-source project with the main goal of promoting FPGA development for SDR and increasing the collaboration between the open-source SDR and FPGA communities. In the first stage of the project, the focus is on the development of a firmware image for the ADALM Pluto that performs most of the signal processing on the Zynq FPGA. A first version already provides the capability of displaying a realtime waterfall display of up to 61.44Msps in a WebSDR-like interface, and recording IQ data at up to 61.44Msps to the Pluto DDR (400MiB maximum recording size). The FPGA design is written in Amaranth, a Python-based HDL. There is an application running on the Zynq ARM CPU that provides a web server with a REST API for user interface and control. It is written in asynchronous Rust. Finally, the user interface is a web application written in Rust and compiled to WebAssembly. It uses WebGL2 to render the waterfall using a GPU. One of the goals of Maia SDR is to provide a portable solution for exploring the RF world in the field, using a smartphone to run the user interface.

14:00 - 14:15 Coffee Break

14:15 - 14:45 Dr. Stefan Scholl DC9ST: Radio Signal Identification with Deep Learning in Real-World Operation

Radio signal identification is the task of detecting the mode or type of an unknown RF signal, e.g. Morse code, SSB voice and RTTY. Recently, deep learning has been investigated as a new promising approach for radio signal identification, where a neural network is trained on large amounts of example signals. However, trained neural networks for RF signals are often only evaluated in academic settings with well-defined synthetic test signals (generated by software simulation) and no data from practical real-world applications. These neural networks may provide good results for synthetic data – but fail, when they face practical operation. This work investigates how training signals need to be designed in order to successfully perform mode identification also in practice. The resulting neural network can identify 20 different shortwave radio signal modes and achieves an accuracy of up to 95% for real-world signals.

14:45 - 15:15 Jakob Ketterl DD5JFK: OpenWebRX - - Recent State of Development

OpenWebRX is an open source web application that allows users to share a software defined radio receiver over the network. It supports a number of analog and digital modulations used, among others, in ham radio.

This presentation gives a short introduction to the application, its use cases and its mission, followed by a technological overview of the internal architecture, and an introduction to the newly developed DSP pipeline implementation.

15:15 - 15:45 André Buhart F1ATB: RemoteSDR - Browser Based SDR Transceiver Control

15:45 - 16:00 Coffee Break

16:00 - 16:30 Murat Sever TA2BTO: Communication Educational Kit - ComKit

Wireless communication has become an indispensable part of our lives. So how does this communication happen? With the “Communication Educational Kit (HaKi)” project, we aim to teach wireless communication in a fun way by experiencing it in the real environment. The kit is a low-cost integrated development environment which includes open-architecture hardware and software and it can be utilized to visualize and process RF signals that exist around us but that we cannot see, for example, to listen to the broadcast from an FM radio station, to analyze the signal coming from the mobile handheld radio or remote control, or to obtain the location and flight information by capturing the signals emitted by the aircraft in the air. The kit can be used to raise awareness and interest in communication systems with a simple user interface at the primary education level. A secondary school student can put his learning in Mathematics, Science and Informatics courses into practice in the communication field with the Python language. Combined with an integrated curriculum at the higher education level, the kit offers a one-place opportunity for students who want to improve themselves in the fields of Communication / Digital Signal Processing / Software Development. Hobbyists, on the other hand, will have all the things they need in order to realize the project they want. In short, the kit has an innovative, low-cost, and extensible structure, making it suitable for users of all ages and levels, and for both in-person and distance education models.

16:30 - 17:00 Dr. Bastian Bloessl DF1BBL: Seify: A Rusty SDR Hardware Abstraction Library

The Rust SDR ecosystem is growing and people start working on the first pure-Rust SDR drivers. This includes HTTP-based drivers (for example for the Aaronia Spectran devices) or Rust reimplementations of C drivers (for example for the RTL-SDR or the HackRF). Yet, the projects are developed independently without a common, compatible interface that would allow wrapping them in a hardware-independent interface for use with Rust SDR frameworks. Seify tries to fill this gap, providing a hardware-abstraction, similar to Soapy in C/C++ domain. While the API surface is identical to Soapy, Seify tries to do it the Rust way and provides several advantages, like typed interfaces. Seify also wraps Soapy as one driver option and is, therefore, compatible with all major SDR platforms. Giving Rust drivers precedence, there is a clear trajectory towards a Rust driver ecosystem, as we can gradually phase out legacy drivers as more and more native Rust drivers become available. Seify is work-in-progress and an invitation to collaborate, aligning driver implementations with a common interface to build a great Rust SDR ecosystem.

17:00 - 17:30 Gerhard Häring DK6RH: Selfmade Portable Hf-Transceiver with Hermeslite2 and Raspberry Pi

The lecture shows a way how to build a mobile SDR-Transceiver with a Hermeslite2 and a Raspberry Pi. The focus of this project is the installation and konfiguration of a CM4-module (quite different to a normal RPi-Board) and a RTC-module for digital modes. Suitable connectors for small cases will also be described.

17:30 - 18:00 Prof. Dr. Michael Hartje DK5HH, Markus Heller, M.A., DL8RDS: Final Discussion

The YouTube stream is available at: https://youtube.sdra.io