Observation and Analysis of Solar Flares that Cause Large-area Short-wave Communication Interruption

When a solar flare erupts, the sun emits a flood of X-rays and high-energy particles that reach Earth at the speed of light, causing a sudden ionospheric disturbance event (SID event). The D layer of the ionosphere absorbs high-frequency radio signals. With the increase of flare intensity, the D layer's absorption capacity becomes stronger, which leads to the decline of shortwave communication quality and even the interruption of shortwave communication. In this paper, solar flares, which caused large area short-wave communication interruption in recent years, are observed and analyzed by very low frequency (VLF) method, and the influence of solar flares on short-wave communication is summarized. Finally, several methods to deal with the short-wave communication interruption caused by solar flares are proposed.

Development of IEEE 802.11 Compliant Antenna with WLAN Mobile Multimedia Messaging Application for Emergency Communication Purposes

In emergency or disaster situations, when communications were interrupted due to damaged local network infrastructures, coordination are affected. Moreover, the deployment of specialized technologies such as satellite and shortwave communication network were found impractical. The objective of the study was first, to construct an improvised antenna that will be tested on an area with no cellular network and test the router’s operating range using it, and second, to design and develop a mobile multimedia messaging application that utilizes WLAN to send data. Results of the testing shows that improvised antenna achieved operating range of 192 meters, the range achieved 215 meters in area with no cellular network, and the application was capable of sending multimedia messages over WLAN