High-frequency Emergency and Rural Multimedia Exchange System

The High-frequency Emergency and Rural Multimedia Exchange System, better known by its acronym, HERMES, provides affordable digital telecommunications over shortwave/HF radio using a simplified visual interface accessed via smartphone or computer, allowing for the transmission and reception of data (chat, audio, documents, photos, GPS coordinates, etc). For security, this information can be easily encrypted and password-protected by the sender. HERMES, both architecture designs and software, is free and open-source.


We are excited that this project was selected as the winner of Mozilla’s Wireless Innovation for a Networked Society (WINS) Challenge, giving us the opportunity to develop the system into something truly useful for isolated communities. We are also happy to announce that in conjunction with Abradig and ISA, the project received support in 2019 to do initial trial deployments and trainings in the Brazilian Amazon.

Full system documentation and source code can be found in the Resources tab below and here.




The Goal

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Reliable and affordable communications in rural and remote places where access to Internet is difficult or non-existent due to isolation or disaster – places generally extremely limited in their back-haul and energy options – as it is too expensive to rent satellite capacity and too slow to install terrestrial links, as well as with regards to access to electricity.

The Idea

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We have set out to create modular, autonomous network infrastructure for use in very remote areas or in post-disaster situations, that assumes no availability of electricity or other communications access. The solution is installable by non-experts, reasonably portable, and fully-contained, allowing for both local and global communications. We aim to facilitate robust local communications and information with limited but useful communications with the rest of the world.

The solution, which integrates GSM and HF backhaul technology, can provide connectivity to places struck be natural disasters or populations living in remote areas. As the system does not rely on cables or satellites, it could also be used as a backup system for primary communications systems.

To ensure coverage and ease of use, the primary user-facing technology is 2G GSM. This is the most widespread digital communication technology in the world and is also minimally battery intensive, meaning users are able connect devices they already own to the network for longer, assuming no grid power is available.

The HF backhaul system was designed with and implemented in Amazon communities in the Brazilian state of Acre as part of the Fonias Juruá project (of which Rafael Diniz is also project lead), which has shown that it is possible to teach local communities to set up HF systems and keep them running for many years.

We have essentially married VoIP, GSM and HF so that users can send a text or voice message from their phone across the world without the need for a satellite.


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  • Transmission mode: Single Side Band

  • RF signal path: Near Vertical Incidence Skywave (NVIS)

  • Channel width: 2.5 kHz

  • Frequencies: between 5 and 7 MHz

  • Power output: 10 W – 100 W adjustable

  • Adaptive digital modulation modes: 4FSK, 4PSK, 16QAM, ranging from 1 to 10 carriers and different symbol rates, all with Reed Solomon Forward Error Correction


There are two sources for HERMES-related software created by Rhizomatica.

First is a dedicated page for the HF part, which can be found here

Second is a branch of RCCN that combines with HERMES and allows for integration of GSM and HF. Code can be found here


Network Diagram


Right-click, View Image for a better view



HF Radio

ICOM 7100 – HF Radio transceiver


Buddipole – Portable HF antenna



MFJ-1778 – Wire Antenna


Astron RS-35A – Power supply (not very portable) for HF radio


12V 50A Switching Power Supply (much more portable)


MFJ-941E – HF Antenna Tuner


Coaxial RF cables with PL-259 connectors


Cellular GSM

SysmoBTS 1020 – GSM Base Transceiver Station


Ventev / TerraWave T09060O10006 – Omnidirectional GSM antenna (outdoor)


Mean Well CLG-100-48 – 48 VDC AC/DC power supply


iCreatin PSE-480080G – POE+ Injector


Coaxial RF cables with N connectors

WiFi and local service

Jetway JBC373F38W-525 – Embedded PC


TP- LINK EAP110-Outdoor – WiFi Access Point


Ethernet / LAN cables


MFJ-1926 – Telescopic fiberglass mast


DX Engineering DXEA15 – Guying Earth Anchors


DX Engineering DXEGR – Guy Rings


80 meters of thin (4mm) nylon rope


HERMES em ação

HERMES Concept Video