[SADXA] Optimum GreyLine-Termination Angle for VK0EK (Heard) / AZ Propagation

Tue Apr 5 14:59:41 EDT 2016

Thanks Bob, 

63 years ago, Scouts started MY Interest in Ham Radio, since we were
required to learn the Morse code to be a 1st Class Scout. Scout Master was a
HAM, and sucked many of us into the hobby, by working a CW station -- right
next to Mars. This led me to an interest and degrees in Electrical
Engineering, and a 30 year Design Engineering / Design Management Career at
Motorola. Funny how life works!!  

At 13, my dipole hung between two trees in back yard of my parent's house.
That was a close enough bearing, to work the next state with 17W on 40m CW!!
Hi Hi. 

Best 73s, 

Bill W7EXG

-----Original Message-----
From: k7bhm at cox.net [mailto:k7bhm at cox.net] 
Sent: Monday, April 04, 2016 5:06 PM
To: Southern AZ DX Association E-Mail Reflector
Cc: W7EXG (Bill)
Subject: Re: [SADXA] Optimum GreyLine-Termination Angle for VK0EK (Heard) /
AZ Propagation

Bill and all..

An excellent analysis of "Gray-Line" and how it effects propagation 
between Arizona and Heard.........Tucson and Phoenix Gray-line being only
a few minutes apart...

63 years ago while learning how to use a compass in Boy Scouts, we
were taught that in Arizona, Magnetic North was always 13 degrees
away (East) from True North. We had to make that adjustment when
locating different objects in the field.

Who would'a thunk the concept was alive and well today with our radios!!!!

Bob - K7BHM

---- "W7EXG (Bill)" <W7EXG at q.com> wrote: 
> The described Greyline bearing vs true Bearing difference of 13 deg would
> not seem to have much difference on a directional antenna's gain. 
> 
> I simulated 13 deg 20m gain loss for a 3 ele SteppIR to be about 0.7dB.
The
> same analysis for my 20m DB42 (5 ele on 42 ft boom) yielded a 1.2dB
> difference. 
> 
> Although this does not seem like much, but when signals are at or near the
> noise level, a 1.2dB signal improvement is helpful. 
> 
> Frequency propagation considerations are uniquely different along the
> Greyline, and uniquely dependant upon the near-side or far-side targets. 
> 
> For near-side, both stations are experiencing the Light to Dark (Dark to
> Light) transition together, while for far-side, one station is progressing
> from dark to light, while the other station is experiencing light to dark,
> or visa versa. This last case, is the case for HEARD. 
> 
> There is no other propagation region on Earth, where over a distance of
> about 1200 miles, the Light side shows a strong D layer, and High MUF with
> F2 layer, while the Dark side shows weak, or no D layer, [with F Layer low
> band DX propagation] and low MUF. I find the MUF gradient interesting
across
> the Greyline.  
> 
> For near-side propagation along the Greyline, both stations start low
> frequency and work toward high frequency, or visa versa, dependent upon
dark
> to light, or light to dark transition respectively. 
> 
> For far-side propagation along the greyline, one station is transitioning
> from low to high MUF, and the other is transitioning from high to low MUF.
> This is a complicated process to accurately predict/model, but may be
> possible. 
> 
> Somewhere in the middle of the near-side/far-side greyline, the
propagation
> works.. 
> 
> I was amazed on 4/2/16 0300Z to 0400Z UTC, VK0EK [11,000 miles away] was
> being heard/worked on 40m, 30m, 20m, and 17m almost at the same time.
Don't
> hear this too often. No place line the Greyline Experience. 
> 
> Greyline propagation is unique, and in some cases it is not clear what
> frequency to utilize, especially for the near-side/far-side propagation. 
> 
> 73s, Bill W7EXG
> 
> -----Original Message-----
> From: SADXA [mailto:sadxa-bounces at mailman.qth.net] On Behalf Of Jerry
Wothe
> Sent: Sunday, April 03, 2016 4:01 PM
> To: Southern AZ DX Association E-Mail Reflector
> Subject: Re: [SADXA] Optimum GreyLine-Termination Angle for VK0EK (Heard)
/
> AZ Propagation
> 
> You have to consider what frequency you are working with also. The dark 
> side is better for the low bands and the sunny side for the higher 
> frequencies. Who is in the dark and who is in the light and when. If you 
> are worrying about where to set your antenna, _+_ 10 degrees, very few 
> antennas are that sharp that you can notice it. Plus depending on 
> frequency the signal my not be best right on the great circle bearing. 
> Lots of antenna rotating goes on right at SR/SS to find out just where 
> is the signal coming from.
> 
> W6XI
> 
> On 4/3/2016 3:06 PM, W7EXG (Bill) wrote:
> > By now, most of us have recognized the two opportunities per day, for
> > propagation between AZ and VK0EK, due to the Greyline.
> >
> > QRZ bearing data shows 186 deg Short Path (SP) (6 deg Long Path (LP))
> >
> > The question becomes: Is this geometrical bearing, the correct bearing
> when
> > Greyline propagation is being considered? I submit the correct answer
is..
> > Not Always.
> >
> > For April 4th, 0140Z UTC, the greyline passing through Tucson, also
passes
> > slightly West of Heard Island. The Greyline Terminator line is along the
7
> > deg / 187 deg line. It is almost the perfect storm, since the Greyline
> > propagation path is close to the required 186 deg SP bearing. As most of
> us
> > know, the evening propagation for VK0EK has recently been exceptional.
> >
> > (HEARD considering staying put!)
> >
> > However, for April 4th, 1300Z UTC, the greyline passing thought Tucson,
> > passes significantly more West of Heard Island. In this case, the
Greyline
> > Terminator line is along the 353 deg and 173 deg line.
> >
> > This suggests the morning propagation may be best at a SP bearing of 173
> > degrees, not 186 degrees (a 13 deg bearing difference)
> >
> > Because of the further west Greyline for HEARD, and an indirect
> propagation
> > path, this suggests the AM propagation between AZ and HEARD may
currently
> > not be as good as in the PM.
> >
> > This analysis is based on the greyline prediction websites.. some of
> which,
> > may not yield identical results. The link below is easy to use, and will
> > verify my analysis above. It agreed with several others greyline
> predictors
> > I tried.
> >
> > https://academo.org/demos/day-night-terminator/
> >
> > 73s, and good luck with HEARD!
> >
> > Bill W7EXG
> >
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