The latest version of the Gyrator series of VLF receivers (first developed in the 1990s) is the Gyrator III, a revision of Arthur Stokes' Gyrator II by Guglielmo Di Filippo (observer A-93).
Circuit diagrams and wiring for the Gyrator III are available here in Microsoft Word and PDF formats: .doc, .pdf
| OBS ID | Observer Name | Station Location |
| A-96 | Roberto Battaiola | Milan, Italy |
| A-97 | Jon Wallace | Torrington, CT, USA |
| A-118 | Lionel Loudet | Muret, France |
| A-119 | Jean-Pierre Godet | le Vauroux, France |
| A-120 | Bob Terrill | Ballarat, Vi |
When the ultraviolet rays from the Sun hit the Earths atmosphere the energy they possess work to knock electrons off of the atoms and molecules that the atmosphere is made up of. These free electrons make up a region of the atmosphere known as the Ionosphere. The region is strongest on the daytime side of the earth since it is dependant on the energy from the solar ultra violet rays.
VERY LOW FREQUENCY (VLF) RADIO STATIONS
Station Station Frequency Radiated
Site ID (kHz) Power
(kW)
U.S.Rodney Howe, Solar Section chair & SID leader
So, what are we looking for? Here are a couple references of SID events and their influence on the ionosphere: