This is a guest post by JH0PCF HIROYUKI Kanda, from Japan.

FreeDV Logging in Japan and the Need for a Bridge Tool

I am HIROYUKI Kanda (JH0PCF), an amateur radio operator in Japan. When FreeDV version 2.2.0 introduced UDP output for received QSO logs, several overseas logging applications—such as KLog—were able to read these packets directly.

However, the situation in Japan was different. Most Japanese amateur radio operators use Turbo Hamlog, developed by JG1MOU (Mr. Hamada). Turbo Hamlog is extremely popular and widely used, but it could not directly receive or import the UDP log packets generated by FreeDV.

FreeDV operators in Japan approached me and said: “We have the binary UDP log data from FreeDV. Could you create a bridge tool that transfers this into Turbo Hamlog?” This request became the starting point for the development of FD Linker.

Human × AI Collaboration in Development

I had no prior programming experience. To make this project possible, I designed the specifications and performed all operational testing myself, while relying on cloud-based AI systems for the coding work.

• Gemini generated the program code
• Copilot reviewed and verified the code
• I handled the design, debugging, and validation

This collaborative workflow allowed rapid development, even during late-night sessions, and resulted in a stable and practical tool for Japanese FreeDV operators. There are two Editions of FD Linker.

This edition is designed for operators who want to accurately record the start time of a QSO:

• Press the Ctrl key when the QSO begins
• FD Linker stores the PC’s internal time
• When FreeDV outputs its UDP log packet, FD Linker parses the callsign,
  frequency, and grid locator
• These fields are automatically entered into Turbo Hamlog
• After confirmation, FD Linker sends the stored start time to complete
  the log

This edition continuously waits for FreeDV’s UDP “Log QSO” packets:

• FD Linker monitors the UDP port
• When FreeDV outputs a log packet, FD Linker immediately parses it
• Callsign, frequency, and grid locator are automatically transferred
  into Turbo Hamlog
• The operator only needs to confirm the entry

Technical Notes:

• Both editions use the public Turbo Hamlog API
• The software is lightweight and single‑purpose
• Development focused on transparency and reproducibility

Acknowledgements

I would like to express my sincere thanks to:

• Experienced FreeDV operators in Japan who provided early feedback
• JG1MOU (Mr. Hamada), developer of Turbo Hamlog
• Gemini & Copilot AI for assisting with code generation and review
• The FreeDV development team for implementing the UDP log output in version 2.2.0
• I am also grateful for the advice I received during the icon design process.

Conclusion

FD Linker was created to help Japanese operators enjoy FreeDV more easily by connecting it to the logging software they use every day. I hope this tool will support the growth of FreeDV activity in Japan and contribute to the global digital voice community.

Best regards,
HIROYUKI Kanda (JH0PCF)
PS: I also manage a Japanese FreeDV information site, including the “FreeDV Operation Guide”: https://freedv.info