This Digital Radio Gets Messages to the World’s Remotest Locations

Shortwave radios are versatile tools for connecting locations on Earth with minimal infrastructure, but they have limited digital data transmission rates. Peter Bloom, founder of Rhizomatica—a nonprofit working with remote and off-grid communities globally—is behind the development of a digital shortwave-radio system called HERMES.

HerMES operates within the high-frequency (HF) band, from 3 to 30 megahertz, and incorporates a digital modem named Mercury. Rhizomatica staff travel worldwide, installing HERMES in remote locations, including Bangladesh, Brazil, and Ecuador, to link locals with the rest of the world. Bloom discussed HERMES’ capabilities in improving data rates and encryption for shortwave radios with IEEE Spectrum.

HerMES employs the ionosphere as a satellite, enabling information, voice, and data transmission across significant distances. Using radios emitting about 20 watts of power, reliable links can be established over 400 to 600 kilometers, connecting remote areas where terrestrial infrastructure is impractical.

Unlike basic voice radios, HERMES uses a software stack to send various file types, including photos, emails, and voice memos, effectively transforming them into data packets transmitted over HF. This capability is particularly crucial in emergency situations, such as sharing precise location data, manifest details, or medical records. Sending files offers more efficiency than voice communication, especially when it comes to providing evidence of illegal activities or sharing critical information quickly.

Additionally, HERMES incorporates encryption, a feature not typically permissible under amateur-radio regulations in many countries. This encryption is optional, allowing users to turn it on or off based on their needs. The encryption ensures that sensitive information shared in sensitive regions remains secure, protecting users from potential misuse of data.

The impact of HERMES has been notable. Rhizomatica partnered with artisanal fishers in Bangladesh, installing HERMES systems on 10 or 11 boats. One incident involved a mechanical issue on a boat in the Bay of Bengal, 100 to 200 kilometers offshore. With HERMES, the fishermen sent their GPS position and a distress signal, enabling the rescue of the crew and the vessel. This real-world application of HERMES highlights its effectiveness in critical situations, delivering tangible benefits to those it serves.