Preliminary result of VLF receiver installation for space weather research

About 40 km altitude, VLF radio waves are partially reflected and partially absorbed by the D-layer of the ionosphere. By measuring the amplitude of radio signals after they have reflected from the ionosphere, it is possible to detect various kinds of ionospheric and space activity taking place. Recently, Division Ionosphere and Telecommunication. Space Science Center, National Institute of Aeronautics and Space (LAPAN) have installed VLF receiver to investigate effects of solar flare to ionosphere, mainly Sudden Ionospheric Disturbances (SIDs). By monitoring transmissions from Earth-based beacons, which are affected by changes in the ionosphere, giving an indirect indication of events on the Sun. The VLF Receiver output is a voltage varying with time, which may be fed to any data logger or digital multimeter. In this paper, we discuss the UKRAA (United Kingdom Radio Astronomy Association) VLF receiver system, our research plan related to this instrument, and the preliminary results of VLF receiver installation.