Wojciech Kaczmarski

Lore & Background

Kaczmarski's work has focused on open-source software and hardware for digital radio communications, emphasizing openly published specifications, permissive licensing, and community-driven development within amateur and experimental radio environments. He has published technical articles addressing signal processing and waveform design for modern digital radio protocols, and elements of this work have been presented at technical amateur radio conferences, including those organized by Tucson Amateur Packet Radio.

He contributed to the development of the M17 digital voice protocol, an open digital radio protocol intended for amateur radio use, discussed as an alternative to proprietary digital voice systems. M17-related work has been presented at international amateur radio and technical events, including those supported by the International Amateur Radio Union. Kaczmarski also worked on the LinHT handheld software-defined radio transceiver, which has been described in amateur radio and technical media, including a cover feature in the German amateur radio magazine CQ DL, and was included in the program of the OpenAlt 2025 conference in Brno.

In 2023-2024, Kaczmarski and co-author Grzegorz Kaczmarek examined the PCSK225 phase-modulated time code transmitted on Poland's 225 kHz longwave broadcast signal, Polskie Radio Program I, and implemented an open-source decoder based on publicly available documentation, clarifying details of the signal format and associated error control codes.

Reader's Guide

Kaczmarski's contributions have been implemented in experimental and commercial radio equipment and have been the subject of technical discussion in amateur radio and software-defined radio communities. Independent publications have examined the design goals and implementation of these systems in the broader context of open digital radio development. His work has been presented at technical conferences and amateur radio events, including meetings organized by IEEE chapters and amateur radio organizations, as well as academic and educational venues, including participation in activities associated with HamSCI focusing on the use of open digital radio technologies in educational and experimental contexts. Commentary on his work has appeared in technical and amateur radio media, focusing on open-source approaches to digital voice protocols and software-defined radio platforms, including both descriptive and critical discussion of design choices and implementation strategies. He has appeared in interviews and media coverage discussing open-source digital radio development, including coverage by independent bloggers, amateur radio publications, and broadcast media in multiple countries.

Did You Know?

• Kaczmarski received the ARRL Technical Innovation Award in 2021 for his work on open digital radio communications.
• He contributed to the M17 digital voice protocol, an open alternative to proprietary digital voice systems.
• He worked on the LinHT handheld software-defined radio transceiver, which was featured on the cover of the German amateur radio magazine CQ DL.
• In 2023-2024, he co-examined the PCSK225 time code on Poland's 225 kHz longwave broadcast signal and implemented an open-source decoder.