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-   SUDDEN IONOSPHERE DISTURBANCE (SID) MONITOR   -

 

If a sudden ionosphere disturbance occurs, the signal level of the observed VLF station (violet graph) will drop or rise quick. The score of the propagation turbulence indicator (PTI) will rise and trigger the alarm. At that moment a automatic tweet will be generated by @SIDdetectorNLD at Twitter.

The yellow graph around the base at -60dB (right scale) is the "propagation turbulence indicator" ( PTI ).
That other yellow sine shape graph is the sun altitude indicator.
The red line at -58 dB is used to show the alarm trigger limit.

The Green graph is the VLF noise level.
Violet is the signal level of the VLF stations who is observed here (ID's in Spectrum graph, below).

Observing location is Appingedam in The Netherlands,  Europe.

The observed VLF station catched in a audio spectogram.