by Jock Elliott, KB2GOM

On the very helpful advice of 13dka, who noted that “this should be optional – the grayline happens twice a day, with the morning grayline favoring westerly propagation paths and the evening grayline the east,” participants in the challenge can now choose either the grey line in the morning as the sun rises, or the grey line in the evening as the sun sets . . . but not both.

Otherwise, the rules remain the same, and the challenge will be open for participation with the grey line at dawn tomorrow.

1. Frequency range is the medium wave band: 520-1710 kHz
2. From one hour before Civil Twilight your local time on Saturday, October 14, to one hour after Civil Twilight at your location . . . at either sunrise or sunset.
3. Any radio with any antenna, but must be the radio at your location (no using remote internet radios)
4. The listener must hear the signal in real time
5. The stations must be ID’ed by listening to the signal.
6. Your report should include:
   • Your name (or Internet handle)
   • Your receiver and antenna (stay with the same setup from beginning to end; if you use multiple setups, provide a separate report for each).
   • Your location
   • The time, the frequency, and the ID of each station heard
   • The total mileage of your top five most distant stations.

Thank you 13dka for the sage advice.

You can find when Civil Twilight begins at your location by visiting www.wunderground.com  . Enter your location, click on “Full Forecast” then scroll down to the “Astronomy” section.