Topband: My first VK on 160M!

[Jim - WS6X]

On Sat, 31 Mar 2018 18:10:08 -0400, Mark K3MSB wrote:

 "Huge day for me this morning....
After several years of trying, I worked my first VK on Top Band! Well,
actually my first 2 Vks!!"

>> First, congrats Mark, for your first VK on 160! We all know the feeling
of stalking a station or country for many years, and the rush of finally
making it! For me it was EY8MM.
This is not to distract from your accomplishment in any way, but I would
have to say, at SR that morning (local) was one of the best openings to the
west since I've lived at this QTH in the Shenandoah Valley. I have worked
both Ron and Luke multiple times, but to make the QSO always required a kW.
That morning, about 20 minutes before SR, I could just begin copying the two
VK3 signals. Right at my SR they both peaked at an honest S9! I had just
fried my linear the night before, but hearing those 2 fat signals was too
much to let pass without a try. I succeeded to work them both with 100
Watts. I only wish there would have been a bunch of other stations from that
area active that morning!
Which leads me to another observation... I have been intrigued by Roger's
(G3YRO) comments about the lack of SR peaking at his QTH. I had observed
that -- sometimes very dramatic -- peaking at local SR for decades in CA.
There I lived in such a suburban noise bag, that I most often depended on
the SR peaking effect to even make the Q.
However, here in VA, I still see the same SR increases in signal strength.
(Witness the above account of the VK3s.) I live way out in the sticks at a
very quiet location. In fact, most of the time my Inv-L hears just as well
as any of 5 RX systems I've used here. I see that SR peak to the west on
both 80 and 160 almost every time the band is open.
Since my location is so quiet, I am reasonably sure that what I'm observing
is true increase in signal strength, not simply an improvement in S/N at SR.
I also assume Roger is savvy enough to recognize the same. 
So, I'm curious... How does geographic location play into this effect? Roger
and I are separated by ~17 degrees latitude. Is that a contributing factor?
Why would this effect at a specific location (like G3YRO's) seem to change
over the years?
Thanks, and again, congrats Mark!
Jim - WS6X