Next Saturday: The Great Medium Wave Grey Line Challenge!

Let’s have some fun for a couple of hours chasing MW DX along the grey line.

Here are the rules:

  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.
  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.

A final point: this is not a contest; it is a challenge. The reward for every participant will be fun and fellowship.

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

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5 thoughts on “Next Saturday: The Great Medium Wave Grey Line Challenge!

  1. David

    Sorry for asking what might appear to be a silly question but is the listening period in the morning or evening as my understanding is that there are 2 periods of civil twilight, one before surise and one after sunset.

    1. Jock Elliott


      Darn good question; sorry it did not make it clear. Civil twilight at sunset. I figured that would be a lot easier for most people.

      Cheers, Jock

      1. 13dka

        Sorry for the late comment but this should be optional – the grayline happens twice a day, with the morning grayline favoring westerly propagation paths and the evening grayline the east (this may be the other way around on the southern hemisphere?).

        Unless you aim for pretty hardcore DX targets, only one of the 2 daily graylines promise may result in DX stations that can be caught with simple equipment. For example, someone on the East Coast may benefit more from the morning grayline putting some South America into focus (besides the continental US still in the dark), while someone on the West Coast may prefer the evening grayline for the same effect. Both have only transoceanic stations along their respective other grayline path, and unfortunately most people will not be able to receive those for a couple of unfortunate reasons .

        An excellent visualization tool is “Simons World Map” from the author of SDR Console (available at the same website).

    1. Jock Elliott


      I will make a post early in the morning on Saturday. Publish your report on your results in the comments to that post.

      Cheers, Jock


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