HF Propagation

Radio and TV signals aren't always limited to traveling line of sight distances. On HF this is commonly caused by refraction (bending) of the signal at the upper layers of the atmosphere known as the ionosphere. On frequencies higher than this, while solar activity plays a role, Earth based weather events are the most common cause of propagation. These links explore several sites, and software, that can be used to help predict how a HF signal will propagate. For propagation topics above 30 Mhz, please see our DXing Above 30 Mhz article.

If you're just getting started in the HF hobby, AE4RV's Propagation Primer is an excellant place to start. Note that you need the most up to date Flash software to view this site.

Links and Online Maps

Links

• AC6V Propagation Links
• EHam Propagation Links
• Ham Radio Online- Radio Propagation Conditions
• Spaceweather.Com

Online Maps

• Grey Line Map
• Hourly Propagation Maps via HFPack
• Earth View great for seeing Greyline
  • Earth View (Mercator projection)
  • Earth view (from above)
• Planetary View another Greyline view
• 4D View of Ionosphere NASA website

Software

• ACE HF
• Geoclock
• SunClock
• VOACap
• VOAProp
• W6ELProp propagation prediction software
• Daylight Clock applet Greyline Display and Clock for the Logitech SqueezeBox series Wifi players.
• Proplab Pro

Technical

• DX QSL Net-Propagation
• DXLC Solar Conditions
• Solar Cycle 24
• HFRadio.org Propagation, Space Weather and Sunspot Cycle Resource Center
• NOAA Space Weather Prediction Center
  • Estimated Planetary K Index
• Solar Terrestrial Dispatch
• The Solar Guide via R Nederlands
• Solar Terrestrial Dispatch
• Topband Propagation
• WM7D Solar Research Page