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 delivering basic healthcare in poor and remote areas. Normally, with proper frequency planning, ionospheric radio will easily connect all field teams in a contiguous area with a radius of 200–400 km. However, in recent years humanitarian organizations reported a “Dead Zone” that occurs at a short distance from the base, with good reception at larger distances. This local communication blackout causes a security hazard to the field crews. This paper investigates the phenomenon, and makes an inventory of its possible causes and drivers.