Propagation

• Earth Viewer
  You can view either a map of the Earth showing the day and night regions at this moment, or view the Earth from the Sun, the Moon, the night side of the Earth, above any location on the planet specified by latitude, longitude and altitude, or from a satellite in Earth orbit. Images can be generated based on a topographical map of the Earth, up-to-date weather satellite imagery, or a composite image of cloud cover superimposed on a map of the Earth.
• IPS Radio and Space Services
  IPS is a unit of the Australian Government Department of Administrative Services and provides the Australian radio propagation and space environment services.
• Make More Miles On VHF -- Solar Activity, Aurora & MeteorScatter
  To give a quick view over current, short-term and longer-term solar, geophysical and meteorstream events, these pages contain links to other pages that are of interest to the VHF radio amateur hunting dx via aurora scatter and meteorscatter.
• MiniProp
  By Sheldon Shallon W6EL -- Still one of the best Propagation programs around.
• OH2BUA WebCluster
  DX-Spots and WWV-information from PacketClusters.
• Propagation
  An excellent article aby Simon Collings, G4SGI.
• Radio Users' Page
  The Space Environment Center of NOAA provides radio operators with current data on the state of the ionosphere.
• Solar Terrestrial Dispatch (STD)
  The Solar Terrestrial Dispatch (STD) provides information regarding the state of the Sun and its effect on the Earth and the space environment near the Earth -- Several new ionospheric services that should be of wide interest to radio communicators (amateur and professional). Every hour, approximately 15 to 20 minutes past each hour, the system regenerates five real-time globally contoured maps of various important and useful quantities:
  • Global Maximum Usable Frequency Maps.
  • Global Maps of the F2-Layer Critical (Penetration) Frequency.
  • Global Maps of the E-Layer Critical (Penetration) Frequency (foE)
  • Global Maps showing the Height Maximum of the F2 Layer
    The altitude above the surface of the Earth where the ionospheric electron density is highest -- Information regarding the likelihood of non-great-circle propagation can also be determined.
  • Global Maps of Solar Zenith Angles
    The distance of the Sun away from the zenith (the point in the sky that is exactly overhead). Shows the elevation angle of the Sun above or below the horizon for any location on the Earth.