WWW Shortwave Listening Guide. The NASWA WWW Shortwave Listening Guide is now closed.
It has become clear that the people behind it no longer have time to maintain the database, and leaving it in place with increasingly misleading listings is no longer tenable. We thank you for your visits over the many years that this resource was available. John Figliozzi now publishes a book, The Worldwide Listening Guide, the successor to the book on which this site was originally based. The book covers all methods of hearing international programs, not just shortwave. Search for SWL Broadcasters by Frequency at HFRadio.org. Welcome! - ILG Software. Hard-Core-DX.com - Probably the best DX site in the world. Grey Line Map. The "grey line" is a band around the Earth that separates daylight from darkness.
Propagation along the grey line is very efficient. One major reason for this is that the D layer, which absorbs HF signals, disappears rapidly on the sunset side of the grey line, and it has not yet built upon the sunrise side. Ham radio operators and shortwave listeners can optimize long distance communications to various areas of the world by monitoring this band as it moves around the globe.