External links

SID and VLF

• Reference website for the D region (in french only)
• AAVSO (American Association of Variable Star Observers) SID Program
• Radio Waves below 22kHz - Articles on VLF, ELF and ULF signals
• SID-GRB@home - A collection of links and information on SID, GRB and various station designs

Solar activity

• SpaceWeather.com - Realtime and archived information on active regions and solar activity
• SpaceWeather.com - News and Information about the Sun-Earth environment
• Space Weather Prediction Center (formerly Space Environment Center - SEC)
• 3-day GOES X-ray Flux Monitor (GOES measurements)
• 6-hour GOES X-ray Flux Monitor (GOES measurements)
• Solar Terrestrial Activity Report, Forecast, Active Solar Regions

Gamma Ray Bursts

• GCN: The Gamma ray bursts Coordinates Network
• GCN Circulars Archive

A few books to go deeper...

• Ionosphère : région D, sondage passif et propagation des signaux LF et VLF Jean-Jacques Delcourt, Hermes Science Publications (in french only)
• Murmures ionosphériques : Techniques de réception sous le seuil de 100 kHz Jean-Jacques Delcourt, Luc Lejeune, Ellipses Technosup (in french only)
• Radio Nature Renato Romero, IK1QFK, Radio Society of Great Britain

Other Sudden Ionospheric Disturbance Observatories

• NCSIDO - Northern Colorado Sudden Ionospheric Disturbance Observatory (Colorado, USA) Station description and real-time measurements
• Moore Observatory VLF Monitor (Kentucky, USA) John Kielkopf's station with access to real-time measurements of NAA 24kHz
• Kiel Longwave Monitor (Germany) Peter Wilhelm Schnoor's station with access to real-time broadband VLF spectrograms
• SID-GRB@home, David Saum's station tuned to the 24kHz NAA transmitter
• Station of Ernst D. Schmitter, Germany, with two VLF receivers 40km apart and a magnetometer

Directories

• DMOZ - Open Directory Project (English))
• Net-Liens Directory (French)