[SADXA] July SADXA Presentation Abstract on Tucson/Heard Island Gray-Lilne Propagation Study

Sun Jul 17 21:35:04 EDT 2016

Dick, 

Yes, perhaps not the best of time to present, in view of vacation travel,
schedules, and RNC convention. 

73s, Bill W7EXG

-----Original Message-----
From: SADXA [mailto:sadxa-bounces at mailman.qth.net] On Behalf Of Richard
Solomon
Sent: Thursday, July 14, 2016 3:29 PM
To: Southern AZ DX Association E-Mail Reflector
Subject: Re: [SADXA] July SADXA Presentation Abstract on Tucson/Heard Island
Gray-Lilne Propagation Study

This sounds very interesting,
I hope everyone gets a chance to
attend.
I am looking forward to it.

73, Dick, W1KSZ

On Tue, Jul 12, 2016 at 9:37 PM, W7EXG (Bill) <W7EXG at q.com> wrote:

>
> To: SADXA Members
> FROM: Bill W7EXG
> RE: Tucson/Heard-Island Gray-line study Presentation - Part 1
>
> Over the past 3 Months, I have studied extensively Gray-line Propagation,
> and especially as it relates to the Tucson / Heard Island Observations.
>
> Unfortunately, this is NOT a LOW BAND Gray-line discussion, since I am
> unaware of any Tucson-Heard 160m or 80m signal data to study. Perhaps the
> mire absence of low band data may be of value. However, I am convinced
that
> many of the lessons learned on the observed 40m, 30m, 20m, and 17m
> Gray-line
> signals, can be applied to the low band cases.
>
> I plan to present part 1 of this study in our July Meeting.
>
> PRESENTATION REPORT:
> Gray-line Propagation: Lessons Learned from the Tucson / Heard-Island
> Experience -- PART 1 of 2 Parts
>
> WHEN: July 21, 2016
> WHERE: SADXA Meeting
> DURATION: ~ 45 min / 15 min Q&A
>
> WHO: Bill Davis -- Licensed as W7EXG in 1956
> Bill is an Electrical Engineer, having retired from Motorola - after
> working
> 30 years, as an Analog IC Design Engineer / Manager. Bill was a Senior
> Member of the Motorola's Technical Staff.
>
> ABSTRACT - PART 1
>
>         This study was motivated by Gray-line Observations of signals
> between Tucson and the Heard-Island DXpedition, by several SADXA members.
> These Observations appeared to challenge or modify both past and current
> definitions and descriptions of Gray-Line Propagation.
>         After a brief review of such definitions and descriptions, an
> observed 40m Long Signal Path is shown as an interesting example of
oddity.
> Starting at night 2500 mi from the Sunset Terminator, this signal traveled
> 3600 mi in DARK, then about 10,200 miles in daylight, 1700 mi and 2.5
hours
> from the Sunrise Terminator. This signal path defied some Gray-line
> definitions such as "Near or Along the Edge of Terminator", or "requires
> Simultaneous Sunrise and Sunset"...etc.
>         Twenty Signal Observations were gathered by 6 members of the SADXA
> group, and were compiled as AM / PM, Long Path / Short Path, Band, and
> Date.
> Six example Timelines are shown for both AM and PM Observations. The
Impact
> of the Kp Solar Indices is discussed, during these observations.
> Eleven questions were raised regarding these observations, such as WHY:
> ALL
> propagation was AFTER Sunrise/Sunset?; NO AM Short Path or 40m Short Path
> propagation?; 40m Long Path observed before 30m long path? Or, how does a
> 40m signal travel over 10,000 mi in the DAY regions, 1700 mi from sunrise
> terminator?
>         A Review of Day/Night Ionospheric Layers is discussed, including
> Day/Night Band Use and Limitations. The concepts and importance of EMUF
and
> MUF on Gray-line propagation are also discussed.
> A review of electron charge distribution for each layer is shown over
> Day/Night Period, including Sunrise and Sunset.
> The important of the EMUF at Sunrise / Sunset is shown to be a critical
> factor in defining Gray-line geographic widths, using a mid band signal as
> example.
>         EMUF is defined in terms of the Critical E Frequency (foE).
> Ionsosndes (Vertical Soundings) foE Data is shown at Sunrise, from a Mid
> Latitude ionosonses Observatory. This foE data supports and explains the
> 40m
> Long Path propagation cited above. The E-Layer electron density and
> Rise/Decay time of foE is considered critical in defining Low/Mid band
> Gary-line geographic width and propagation. The foE data also demonstrates
> ionization in Twilight region, prior to Sunrise.
>         MUF is defined in terms of the Critical F Frequency (foF2). Using
> foF2 Data, World Color (MUF) Maps are shown for specific Tucson-Heard
> Propagation dates, and times. Long or Short Signal Paths are superimposed
> on
> these MUF maps as a function of time,  which explains the observed
timeline
> delays and durations, as well as the viability of Long or Short Paths for
> AM
> and PM propagation.
>         Finally, the 11 questions raised by the Tucson-Heard Observation
> data are reviewed and answered based on the preceding discussion.
>
> Part 2 presentation is planned, during September SADXA meeting. There is
> actually much more to say, such as ionization in the DARK region at
> Sunrise,
> effects of E and D-Absorption, Solar Indices effects, Band dependant
> Propagation Corridors, and Daily, Seasonal and Annual Angular World
> Coverage... etc.
>
> Best 73s,
>
> Bill W7EXG
>
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