[SADXA] Terminator Speed at HEARD and DAYLIGHT Propagaion Distance of Greyline, after Sunrise

[Wes]

A suggestion that before getting too wound up about this, a look at this 
presentation might be "illuminating."

http://wwrof.org/webinar-archive/a-long-overdue-review-of-gray-line-propagation-on-the-low-bands-by-carl-luetzelschwab-k9la/

On 4/6/2016 9:22 AM, W7EXG (Bill) wrote:
> The Earth's Terminator Speed at HEARD is 623 mi/hr at -53 deg latitude.
>
> Since on 4/5 AZ time, VK0EK's signal was heard 2 hrs and 25 min. AFTER
> VK0EK's SUNRISE, the GREYLINE daylight propagation path DISTANCE AFTER
> SUNRISE (distance from Heard to westward moving Terminator) was  1505 miles.
>   
> This is an amazing distance, for a 40m signal to propagate in daylight,
> just to travel to the actual Greyline boundary [not to mention the 11,000
> miles around the world to Tucson].
>
> I guess it really doesn't come as a surprise to many,  based on the Easterly
> Stations still heard on 40m at Sunrise.
>
> To me, all this strongly suggests the D layer is slow to materialize after
> sunrise.. It is well known, the D layer quickly dissipates AFTER SUNSET.
>
> The reason I find this important for DX chasers, is this data suggests the
> actual propagation BAND of the Greyline, appears to be well over a 1000
> miles on the SUNRISE side of the Earth's visible light terminator.
>
> This might have value to some, in planning a GREYLINE DX target timeframe
> window.
>
> 73s,
>
> Bill W7EXG
>
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