High-frequency Emergency and Rural Multimedia Exchange System


We are excited that this project has been selected as a promising idea by Mozilla’s Wireless Innovation for a Networked Society (WINS) Challenge and look forward to developing it more over the coming months. Full system documentation and source code can be found in the Resources tab below.




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.

The Team

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  • Rafael Diniz – the newest member of Rhizomatica and a PhD candidate at University of Brasília in Computer Science. Rafael has been coordinating a project in the Brazilian Amazon called Fonias Juruá to provide connectivity using stock narrow band HF radios and SDR tools.
  • Keith Whyte – Rhizomatica Technology Coordinator.
  • Peter Bloom – Rhizomatica Founder and General Coordinator.
  • David Rowe – holds a PhD in signal processing, and is a world leader in low bit rate speech compression and HF modems, with a focus on combining these technologies for digital voice over HF radio applications.
  • Dr. Marco Zennaro – a researcher at the Abdus Salam International Centre for Theoretical Physics (ICTP) in Trieste, Italy, where he coordinates the Telecommunications/ICT4D Laboratory and a Visiting Professor at Kobe Institute of Computing (KIC) in Kobe, Japan.
  • Ermanno Pietrosemoli – founder and current president of Escuela Latinoamericana de Redes (EsLaRed), an organization that has been promoting information and communications technologies in Latin America since 1992. Since 2010 he is a full-time member of the Telecommunications/ICT4D Laboratory at the International Centre for Theoretical Physics (ICTP) in Trieste, Italy.


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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