A basic study of the near vertical inclined skywave: The last survival tool of radio communications to support telemedicine after N-disaster

For years, we have studied the Near Vertical Inclined Skywave (NVIS) to support telemedicine after major N-disaster. In the case of disaster and emergency situation, communication infrastructure availability is one of the key points for success of telemedical services: coordination among the medical personnel, monitoring of evacuation or treatments to the patients. However it is often happened that telecommunication infrastructure is not functioning in this situation because of damage or malfunction due to disaster or blockage because of high traffics, which is typical in cellular system. HF communication gives a good possibility to communicate during disaster, as it is cheap and easy to establish. The NVIS is a HF method to reach area at the radius between 80-113 km from the sender. This area is normally not reachable by the ground wave communication or conventional HF communication. This paper discuss about the features of NVIS communication and performance simulation with Pact communication.