Mirko S57AD, congratulations! I'm much closer to Alaska and I only work
Alaska a couple times a year on 80M.
I have been a ham for 39 years now, but I am a "newbie" to 80M. I never had
an actual 80M antenna until 2008.
The first week I had my 80M antenna up, I didn't "know" that "80M was only
a nighttime band" and I would go CQ on 80M before my sundown. That's how I
worked VK6HD on 80M while it was still daylight outside :-)
I have since gone on to place high in DX Marathon 80M category several
years in a row. Never #1 but up there.
Only a handful of my 80M DX contacts are made while the sun is above the
horizon on both ends, almost all are purely conventional pure-dark paths or
at least deep-dark-on-one-end paths.
That's in contrast to, say, long path on 40M to JA in my winter afternoon.
That's seems quite common in comparison.
A truly captivating study of 80M grey line was made and published by N4II.
He analyzed the grey line paths from Cocos-Keeling to W4 on 80M. He
published a QEX article that explores grey line through log statistics,
propagation models, and truly excellent anecdotes who caught rare DX on 80M
via grey line. A powerpoint presentation by N4II has many of the details
and highlights: http://www.qsl.net/k4fk/presentations/VK9C-W4.pdf
N4II's article and presentation deserves some kind of award. It is the
pinnacle of ham radio excellence as it combines theory, data, and reduction
to practice in "catching the big one".
Tim N3QE
On Fri, Feb 17, 2017 at 1:36 PM, S57AD <mirko.s57ad@gmail.com> wrote:
> W6EL prop program helped me to work my first (and single, so far) Alaska on
> 80m some 20 years ago.
>
>
> 73, Mirko, S57AD
>
> 2017-02-17 18:50 GMT+01:00 Merv Schweigert via Topband <
> topband@contesting.com>:
>
> > I agree seat time is the only sure way. I have tried a number of
> > different prop programs
> > and have not been satisfied so to speak.
> >
> > What I use now most of the time does not specifically show grey line, but
> > does do long
> > and short path, and you can "estimate" grey line by the sunrise / sunset
> > times shown
> > and the path predictions to the destination.
> >
> > It is the old old W6EL prop program.
> >
> > For me it has been very accurate in predicting openings, simple to use.
> > Have been able to snag needed countries on the low bands using this tool,
> > its interesting
> > to be sitting on the freq and hearing just whispers of the DX, and as the
> > time plotted
> > by W6EL approaches the signal comes up out of the noise and you have a
> > shot at
> > working them.
> > Some times the window is very short, but it seems to be pretty accurate
> > as to time / freq.
> > It only covers 80 to 10 meters by the way.
> >
> > 73 Merv K9FD/KH6
> >
> > Hello Kris N5KM,
> >>
> >> Thanks for the clarification.
> >>
> >> 80m is a different story. Yes, we can predict greyline propagation on
> 80m
> >> (I assume when you say greyline propagation, you mean propagation along
> >> the
> >> terminator). And our predictions say there is still significant loss
> along
> >> and near the terminator on the low bands. Simply put, absorption is
> >> proportional to the product of electron density times electron-neutral
> >> collision frequency - so as we progress from day to night, absorption
> >> moves
> >> up from the D region to the lower E region. There is still a prohibitive
> >> amount of absorption along the terminator on the low bands.
> >>
> >> What I and others believe is that what really happens is the RF takes a
> >> short cut across the dark ionosphere, where absorption is minimal. The
> RF
> >> gets far enough away from the terminator to minimize absorption, but not
> >> far enough away to look like it's not greyline. Thus the importance of
> the
> >> greyline is to put both ends of the path in or near darkness. For a
> great
> >> article on 80m greyline, read Ed N4II's article in the Nov/Dec QEX
> titled
> >> "Gray Line Propagation, or Florida to Cocos (Keeling) on 80m". I have
> >> written about the problems with "greyline propagation" numerous times,
> but
> >> N4II's article is more elegant!
> >>
> >> So can we predict this alternate explanation of greyline? Unfortunately,
> >> no
> >> - as it involves two great circle paths joined by a skew point. Having
> >> said
> >> that, many years ago Rod VE7VV developed a DOS program to address these
> >> skewed paths. I am not familiar enough with it at the moment to offer
> any
> >> comments. I believe Bill W4ZV has used it more extensively. One comment
> -
> >> the output of this program appears to be in terms of a monthly median,
> >> since the model of the ionosphere in our prediction programs is a
> monthly
> >> median model. In other words, VE7VV's predictions say something like a
> >> signal will be so many dB above 0.5 uV on a percentage of days.
> >> Unfortunately, we do not know which will be the good days. Bottom line -
> >> keep you butt in the chair at the appropriate times.
> >>
> >> Carl K9LA
> >> _________________
> >> Topband Reflector Archives - http://www.contesting.com/_topband
> >>
> >>
> > _________________
> > Topband Reflector Archives - http://www.contesting.com/_topband
> >
>
>
>
> --
> Mirko S57AD
> _________________
> Topband Reflector Archives - http://www.contesting.com/_topband
>
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