When did hams start paying attention to gray-line propagation effects?

Discussion in 'Ham Radio Discussions' started by W7UUU, Apr 16, 2018.

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  1. W7UUU

    W7UUU Super Moderator Lifetime Member 133 Administrator Volunteer Moderator Platinum Subscriber Life Member QRZ Page

    Now we're talking!! That's the sort of thing I was looking for just couldn't find the right words!!

    Homebrew solutions to view something easy to see via computer, but not so much in the era prior to computers being common

  2. KA2CZU

    KA2CZU XML Subscriber QRZ Page

    sorry, yeah.... the "point" often flies right by me :(

    so, that out of the way, here's the first calculator I can find:

    NK2U likes this.
  3. WD0BCT

    WD0BCT Premium Subscriber QRZ Page

    I suspect the term "gray line" was coined once we got into the computer generated global sunset and sunrise locations. I recall global map "gray line" wall clocks clocks beings used by a satellite monitoring outfit I worked at in the mid 90's. However, operation during the sunrise and sunset period was always considered as a good operating MO if interested in DX as young ham in 1974. We may not have been aware of where the physical gray line was globally...but we were aware of it at our QTH.
  4. KB2FCV

    KB2FCV Ham Member QRZ Page

    Trying to remember how it was in the late 80's / early 90's before the web... being on the air a lot.. you tend to discover what you hear, on what bands.. and when. While I didn't have exact greyline timing.. you just sorta knew / learned what you would hear when and where. Some days would be better or worse than others. I don't recall if it was ever discussed to much in detail, but then again I wasn't a part of any serious dx clubs back then (nor am I now). There is a DX club nearby that's been around decades where it probably has been discussed and well known for decades upon decades.

    The geochron clocks are pretty. If I had the money to burn I'd have one hanging in the shack but I'd have a long list of other things I'd want to spend money on first.. besides I can just have it sitting open in a web browser if I needed it.. or better yet just turn on the radio and spin the VFO :)
  5. W6RZ

    W6RZ Premium Subscriber QRZ Page

    In the early editions of "80 Meter DXing" by ON4UN, this gray-line globe from Columbus-Verlag was featured. It was internally illuminated to show the terminator.

    VK2WP, AG5DB and KA2CZU like this.
  6. W6RZ

    W6RZ Premium Subscriber QRZ Page

    The original gray-line article was by K6UA and W6NLZ in the September 1975 issue of CQ.
    KA0HCP and KA2CZU like this.
  7. KA2CZU

    KA2CZU XML Subscriber QRZ Page

    I was just looking for discussions around long path propagation and am leaning towards the same idea that it was discussed but not called out specifically regarding the day/light terminator. Partly because of the different effects at different frequencies, the height of differing ionized layers etc.
  8. N4OGW

    N4OGW Ham Member QRZ Page

    One pre-internet device was the "DX Edge":


    Lots of people use the term incorrectly...the low band sunrise/sunset enhancement is different from propagation along the greyline. The late N4KG explained it well:


    For the low bands knowing your and the target sunrise/sunset times are mostly what you need even if you don't have a full graphical visualization of the greyline on the globe.

    W2AI, WZ7U, W7UUU and 1 other person like this.
  9. KD0CAC

    KD0CAC Ham Member QRZ Page

    When I found out there was such a thing , Technician Study Guide ;)
    W7UUU likes this.
  10. W3WN

    W3WN Premium Subscriber QRZ Page


    I can’t give you an exact date, but I know people talked about grey line back when I was on the contest team at K3CR (as a very junior operator), going back to before Sweepstakes SSB in November 1975.

    I know there were a few books written about it, as well, at least in the 70’s and probably earlier. At the time, I had so much to learn that I didn’t pay attention to those details.

    A lot of “grey line” work, pre-internet, was done by seat-of-your-pants efforts. As in manually tracking approximate local sunsets/sundowns (via newspapers and other calculations, by hand for the most part), then trying to be in the shack at the right times and hoping for the best.

    A lot of the big-guns at the time did this, but rarely talked openly about it. It was kind of a ‘trade secret’ that many used to maintain their ‘edge.’
    W7UUU likes this.

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