Introduction

Telecommunication in the HF Band using skywave propagation offers hundreds to thousands of kilometers coverage with relative low power and simple antennas, but it is also challenging, given the extreme limitation on throughtput and very long transceiver turn-around times between tx and rx.

HERMES is a digital telecommunication system for the HF band, which uses a high-performance HF modem and UUCP (Unix-to-Unix Communication Protocol), for email transport and other ad-hoc services. UUCP is arguably the most relevant store-and-forward system to date, in use since the late 70's for software exchange, email, bulletin board systems news and even military communication. First released in Bell Labs' Unix Version 7, it is still present in all major Unixes (including Linux) and integrate seamless with email software like Postfix.

Upper network layers are composed by email software infrastructure and Web Interface for management and access to the services. HERMES network topology is flexible, but tipically configured as star, with a “gateway” station located where Internet is available (in order to route data from stations located in isolated areas) and “remote” stations located at communities without access to other telecommunication systems.