ad: SDRKits-1

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

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

ad: L-HROutlet
ad: l-rl
ad: Left-2
ad: abrind-2
ad: L-MFJ
ad: Subscribe
ad: Left-3
  1. W7UUU

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

    Over the last few years I've learned quite a lot about what to expect for gray-line propagation, and the twilight effects on both the D and the F layers. I've had especially good results on the lower bands (80/40) with less-than-ideal antennas, working some great CW DX on 80 at the crack of dawn that would not have been possible 2 hours before or 2 hours after. I never paid attention to this phenomenon prior to 2010 or so.

    But what I have noticed is there isn't much mention of gray-line prior to the Internet Age. In fact, almost none. I've checked all the ARRL handbooks I have going back decades, and there's no mention of gray-line at all in the sections on "propagation phenomena". At least none I've found.

    It would appear that prior to the Internet, the only way to really visualize the terminator and resulting gray-line was to go out and spend a heap of cash on a Geochron mechanical sun clock, customized for your location. Now granted, the first Geochrons were sold in the early 1960s.

    But realistically, only a tiny percentage of hams could afford one back then. You could certainly graph it on paper, but no sooner had you started graphing it would have changed again! Without a Geochron (in essence an analog computer) or modern digital computer, there really was no practical way to do this.

    Lots of internet searching only turns up the myriad visualization programs and sites to view the gray-line at any moment in time, but nothing really describing the history of "hams paying attention to it" or other radio services for that matter (surely SW BC stations were aware of the phenomena and built schedules around the gray-line over the course of a broadcast year).

    Curious: when did you start paying any attention to gray-line propagation effects? Does anyone know when the phenomenon was first noted in ham radio circles?

    N7ANN and NW7US like this.
  2. W4NNF

    W4NNF XML Subscriber QRZ Page

    You didn't need an expensive Geochron clock. I recall charts and paper sliderule like widgets being used long before their were those fancy clocks.
  3. W7UUU

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

    I would imagine such but have not found any ads, images or articles describing them. Doesn't mean they're not out there - just I haven't found them. Googling Gray-line is like Googling a celebrity name - you get millions of hits, but the quality is lowered because there is so much "noise" between valid hits

    I'd love to see ads for these "sliderule like widgets" - I can certainly picture what they would be like but have turned up pretty much nothing

  4. K1FBI

    K1FBI Ham Member QRZ Page

    I got turned on to this program years ago by a local ham. It made a big difference in my contacts.

    It is excellent for gray-line.

    The other big tip he gave me was world time; can't work 'em if they're sleepin'.
    Last edited: Apr 16, 2018
  5. W4NNF

    W4NNF XML Subscriber QRZ Page

    In the 80s, I seem to recall having a Commodore 64 program that drew a grayline chart. :)
    KA2CZU likes this.
  6. KA2CZU

    KA2CZU XML Subscriber QRZ Page;wap2

    I dunno... a simple search turned up a number of useful links with articles back to '92 (perhaps earlier).

    I seem to remember discussions about this from the 80's onward when I was active.... early or pre "usenet" days.
  7. N7ZAL

    N7ZAL Ham Member QRZ Page

    I don't remember any "techniques" but you developed a sense of what DX locations would be open by the clock. This was in the 1950s. A little observation and it was determined that around sunset at our location and a few hours into the night was best for European/African DX. Pacific areas were around the early AM hours.

    That was for 20 meters. Each band had it characteristics.

    I suspect the military had something but never heard of it.
    KC8VWM likes this.
  8. W4NNF

    W4NNF XML Subscriber QRZ Page

    I went googling too, but didn't find one, a sliderule for grayline calculations, that is. I did find the crazy cool (well crazy, anyway) online version of the infamous nuclear weapons effects sliderule! ;)

  9. W7UUU

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

    Yes, but..... my question is what was done prior to modern computers and the Internet? When did hams first start trying to use Gray-line as a reliable propagation means prior to modern technology?

    I'm not looking for all the myriad modern computer programs and web sites :)

  10. W7UUU

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

    Still missing the point - all of those resources reference computers or Geo-clock devices of modern (80s or newer) conception. I'm trying to go back BEFORE all the modern tech. 1930s? 1940s? 1950s? Early 1960s? And if so, what were they using to calculate things?

    When did hams start using gray-line without digital computers, Usenet, Geochron clocks, IBM mainframes, etc.

    There's very little history in where gray-line watching began. Maybe it wasn't until computers - I don't know. But that's the nut of the question.


Share This Page

ad: elecraft