This blog post details the creation of an open-source DMR (Digital Mobile Radio) transceiver using software-defined radio (SDR) with GNU Radio and the Codec2 vocoder. The author outlines the process of building the system, highlighting the integration of different components like the MMDVM modem, a modified version of the AMBE codec (Codec2), and GNU Radio for signal processing. The implementation allows for real-time DMR communication, demonstrating the feasibility of building a completely open-source DMR system. This project offers an alternative to proprietary DMR solutions and opens possibilities for experimentation and development within the amateur radio community.
QRP Labs has released beta firmware enabling SSB (single-sideband) transmission and reception on the QMX transceiver. This firmware adds upper and lower sideband modes, along with a new CW mode with adjustable sidetone frequency and a wider range of speeds. Existing features like digital modes, FreeDV, and the touch-screen interface remain functional. The SSB implementation is still considered beta and requires careful tuning, particularly regarding microphone gain settings to avoid overdrive. Users are encouraged to provide feedback to help refine the firmware before its official release.
The Hacker News comments express significant excitement about the new SSB firmware for the QRP Labs QMX, praising its features and Hans Summers' (the creator's) work. Several commenters discuss their pre-orders and eagerness to try it out, noting the impressive performance achieved in such a small and affordable package. Some discuss the complexities of SSB implementation compared to digital modes, while others appreciate the continued support and updates for the QMX platform. A few express interest in its potential for portable operation and digital modes like FT8. Overall, the sentiment is very positive, reflecting a high level of anticipation and satisfaction within the amateur radio community.
The TinyTen is a compact, highly portable, and experimental high-frequency (HF) transceiver built around a low-power DSP. It utilizes direct digital synthesis (DDS) for both transmit and receive, covering 160 through 10 meters, with a maximum output power of 1W. The design prioritizes simplicity and small size, featuring a minimalist user interface with a single rotary encoder and a small LCD display. It requires an external computer for initial configuration and incorporates readily available components for easier construction by amateur radio enthusiasts. Despite its experimental nature, the TinyTen aims to deliver a functional and portable HF experience.
Hacker News users discuss the TinyTen transceiver with interest, focusing on its impressive DSP capabilities and small size. Several commenters express admiration for the project's ingenuity and the author's clear explanations. Some discuss the trade-offs of DSP-based radios, noting potential performance limitations compared to traditional analog designs, particularly regarding dynamic range and strong signal handling. Others are curious about the specifics of its DSP implementation and the choice of components. A few share personal experiences with similar projects and offer suggestions for improvements or alternative approaches. The overall sentiment is positive, with many praising the project as a fascinating example of modern radio design.
A hobbyist built a low-cost, DIY plane spotting system using a Raspberry Pi, a software-defined radio (SDR), and a homemade antenna. This setup receives ADS-B signals broadcast by aircraft, allowing him to track planes in real-time and display their information on a local map. The project, called "PiLane," leverages readily available and affordable components, making it accessible to other enthusiasts. The website details the build process, software used, and provides links to the project's source code.
HN commenters generally praised the project's ingenuity and execution. Several appreciated the detailed blog post explaining the hardware and software choices. Some questioned the legality of publicly sharing ADS-B data, particularly decoded Mode S messages containing identifying information. Others offered suggestions for improvement, including using a Raspberry Pi for lower power consumption, exploring different antenna designs, and contributing to existing open-source projects like ADSBexchange. The discussion also touched on data filtering techniques, the range of the system, and the possibility of integrating ML for aircraft identification. A few commenters shared their own experiences with similar projects and related technologies.
Summary of Comments ( 5 )
https://news.ycombinator.com/item?id=43735945
Hacker News users expressed excitement about the open-source DMR implementation, praising its potential to democratize radio technology and make it more accessible for experimentation and development. Some questioned the legality of using DMR without a license and the potential for misuse, while others highlighted the project's educational value for understanding digital radio protocols. Several comments focused on the technical aspects, discussing the challenges of implementing DMR, the performance of Codec2, and the potential for integrating the project with existing hardware like the HackRF. A few users also expressed interest in similar open-source implementations for other digital radio protocols like P25 and NXDN.
The Hacker News post titled "Open Source DMR Modem Implementation in SDR with GNU Radio and Codec2" has generated a moderate amount of discussion, with several commenters expressing interest and raising pertinent questions.
One of the most compelling threads involves the licensing of the Codec2 voice codec used in the project. A commenter highlights potential GPL licensing implications when combining Codec2 with GNU Radio, which is also GPL licensed. This sparks a discussion about the nuances of GPL licensing and whether static or dynamic linking of Codec2 affects the overall licensing requirements of the project. This thread is important as it raises practical concerns for anyone looking to build upon or modify this open-source project.
Another commenter questions the choice of DMR, pointing out that it is a proprietary standard controlled by Motorola. They express a preference for open standards and question the long-term viability of building upon a closed standard. This raises a valid point about the potential limitations and risks associated with relying on proprietary technology.
Several commenters delve into technical details, discussing the challenges of implementing DMR, including the complexities of its two-slot TDMA structure. They also discuss potential applications of the project, including using it for emergency communications and amateur radio.
Some users also share their experiences with DMR and other digital voice modes, providing valuable context and insights into the practical use cases of such technologies. They discuss the tradeoffs between voice quality, bandwidth efficiency, and complexity.
Finally, a few commenters express excitement about the project and commend the author for their work, recognizing the potential of open-source DMR implementations to foster innovation and experimentation in the field of digital radio.
Overall, the comments section provides a valuable mix of technical discussion, licensing concerns, and practical considerations related to the open-source DMR modem implementation. It highlights both the promise and the challenges of working with open-source and proprietary technologies in the realm of digital radio.