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

[W7EXG (Bill)]

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