Studying and analysis a VLF radio waves reflection from the ionosphere layer in Thi-Qar Site

Abstract EN

Very Low Frequency (VLF) transmitter signals propagate in guided modes through the earthionosphere waveguide (EIWG) with very little attenuation and can be received literally around the globe.

The measurements of the amplitudes of VLF signals is the most cost effective method for studying the propagational features of VLF waves in the EIWG and probe the transient ionospheric disturbances in the D-region.

Our space weather monitors measure the effects on Earth which produce by solar flares by tracking the changes in VLF radio transmissions as itreflected by ionosphere.

Solar Center at Stanford University's has developed an inexpensive space weather monitors that students can install and use .

The instruments detect changes to the earth’s ionosphere caused by solar flares and other disturbances.

A Super SIDs receiver was installed in the location of the Faculty of Science - University of Thi-Qar , to start the project through the design of our antenna.

Data collection and analysis is handled by a local PC .

VLF signals from the five navigational transmitters; 1) TBB , Turkey (26.7 KHZ), 2) DHO38 , Germany (23.4 KHZ) , 3) HWU , France (21.75 KHZ), 4) GQD , UK (22.1 KHZ) , 5) NON , Occupied Palestine (29.9 KHZ) continuously from May 2017 to 15 September 2017 and analyzed to accomplish the scientific objectives of this work.

The signal strengths vary over the 24-hour period due to varying illumination of the transmitter receiver great circle paths (TRGCPs) by the sun.

The night and day time signal strengths are different from each other due to the change in the reflection conditions at the lower ionosphere.

Besides this, the signal strengths are largely affected by the discontinuity over the day and night propagation paths at the terminator which results in signal fading (minima) during sunrise and sunset transition of the terminator.

Effects of solar flares that occurred during the monitoring period on the amplitudes of five VLF transmitter signals as mentioned earlier have also been studied.

The amplitude enhancements of 1.3-15 dB for the solar flares of classes B9.2 - X9.3 respectively have been observed.