Shortwave radios enable global communication with minimal infrastructure but suffer from low data rates, typically hundreds of bits per second. Peter Bloom, founder of Rhizomatica, a Philadelphia-based nonprofit, developed HERMES (High-frequency Emergency and Rural Multimedia Exchange System), an open-sourced digital shortwave-radio set operating in the HF band (3–30 MHz). HERMES uses the ionosphere to relay signals, enabling reliable 400- to 600-kilometer links with 20-watt radios.

It functions as a software stack that sends any file—photos, emails, voice memos, GPS data—over HF, overcoming the limitations of basic voice radios. Encryption is optional due to varying amateur-radio regulations, protecting sensitive communications in high-risk areas. Rhizomatica has deployed HERMES with artisanal fishers in Bangladesh, where a boat in the Bay of Bengal, 100–200 km offshore, used the system to send its GPS position and an SOS during a mechanical failure, enabling a successful rescue.

HERMES provides critical data transmission for emergencies, telemedicine, manifests, and evidence collection in remote, off-grid regions where terrestrial infrastructure is impractical. The system was featured in the October 2026 print issue of IEEE Spectrum as “Peter Bloom.”.