Welcome

You are on the Sudden Ionospheric Disturbances Monitoring Station A118 website. Welcome!

The solar flares release energy that affect the near Earth environment and particularly a part of the atmosphere called ionosphere.

Through monitoring of the propagation of radio communication signals, this station aims at detecting some of the ionospheric effects resulting from solar flares. Those effects are known as Sudden Ionospheric Disturbances, or SIDs.

This station is an amateur observatory located in France. Operational since early 2006, it has received the AAVSO observer code A118 in July 2006 and provides data to a coordinated network of observers around the world.

This website gives you access to real time measurements collected by the station and to a database of SID events observed so far.

I have also include general and basic information related to ionosphere, and to Sudden Ionospheric Disturbances and their detection principle.

This website aims also at providing information for building your own station. The construction of the various parts is described: the VLF antenna, the VLF receiver and the data acquisition and processing software.

I hope you will enjoy this site. Comments and suggestions are more than welcome, so do not hesitate!

The origins...

Early 2005, a Sky & Telescope article mentioned the recording by an amateur astronomer of the effect of a GRB (Gamma Ray Burst) on the Earth ionosphere. This amateur was monitoring radio signals transmitted by VLF (Very Low Frequency) stations hundreds to thousands miles away.

As a child, I used to spend many hours in astronomy books or under the skies. Today, professional constraints impose me to live under light polluted skies and to be less and less available for watching the stars. The monitoring of SID (Sudden Ionospheric Disturbances) appeared to me as a good means to come back to astronomy and gave me the opportunity of discovering a whole new world...
Less than a year after reading the S&T article, after hundreds of hours surfing the web and seeking information, making the VLF receiver and writing software, the SID Monitoring Station was operational.

Latest News

Happy New Year 2010

01 Jan 2010 14:15 UTC

I wish you and your loved ones a very Happy New Year!

GreatCircle and LocConverter software

28 Dec 2009 15:55 UTC

Two new tools are available in the "Utilities" section:

GreatCircle caculates distance and bearing betweeen two locations on Earth, as well as the location of the subreflective points on the path.
LocConverter converts coordinates between the Maidenhead locator system and latitude/longitude.

[Read More...]

Addition of yearly plots

19 Dec 2009 22:45 UTC

A new tab gives access to a yearly representation of the evolution of the signal levels of DHO38 for the years 2006, 2007, 2008 and 2009.

[Read More...]

Empirical Mode Decomposition of VLF measurements

14 Dec 2009 06:22 UTC

A new option allows to display the EMD of the VLF signals measurements.

[Read More...]

Application of Empirical Mode Decomposition to the detection of Sudden Ionospheric Disturbances

05 Dec 2009 22:12 UTC

The author has written a paper on the application of Empirical Mode Decomposition (EMD) to the detection of Sudden Ionospheric Disturbances (SIDs). The results suggest a greater confidence in the detection of the events and a reduction of the detection limit from C1 to B5. A methodology for determining precisely the disturbance timing is also proposed.

[Read More...]

[View News Archive...]