Escaping the Dead Zone: a Bottleneck in Humanitarian Ionospheric Radio Communications

High Frequency (HF) radio communications are used in humanitarian work in areas where local networks are non-existent, or destroyed by natural disaster or human conflict. Direct point-to-point communications are realized over long distances, independent of local networks, using the ionosphere as a natural high-altitude reflector. HF ionospheric radio is essential for humanitarian organizations del...