Doing long distance digital links using the HF radio band / Rhizomatica's HERMES project in Mexico
Rafael Diniz, Keith Whyte
In this talk we will present the system we used in the HERMES (High-frequency Emergency and Rural Multimedia Exchange System), winner of the Off-the-Grid Internet Challenge of Mozilla WINS Challenge.
At HERMES demonstration in Mexico the system was composed by a couple of ICOM IC-7100 radios (100W peak output power), doing NVIS (Near Vertical Incidence Skywave) skywave communication between a community in the mountains and capital of the state. An SDR modem designed to be used with standard HF transceivers, and the software to connect everything (including the Osmocom GSM stack) together with a GSM BTS were assembled to provide emergency communication to any isolated place.