George W8UVZ wrote back
<<As u probably recall, three of us are active on 160M here in Battle Creek.
All of us agree that contacts from here to northern EU are most non existent
during these condx. Same is true in the AM to Japan.
Believe IV3PRK is south of us in latitude - maybe the effect is minimized at
his QTH but I can honestly say it is not here.>>
Good point, George. This is something I brushed over in the article, and
should have stressed more. I think there's a misconception of where the
increased absorption of a stratwarm occurs. From all the literature I've
dug up (mostly from the German community, as they first observed increased
absorption at low frequencies during daylight hours concurrent with a
stratwarm back in 1952 in the Berlin area), the increased absorption is not
in the polar cap area (over the poles) - it's equatorward (south) of the
polar cap. That's why the Italy to US path seems to be a nice fit - it goes
right through the areas where the literature says the increased absorption is.
As for your observations, all I can say is I hope you separated out the
k-index so that "bad" days were indeed due to a stratwarm, and not due to a
high k-index. If the variables aren't controlled, then the conclusion isn't
worth a hill of beans (been there, done that).
I'm not too far south of you here in Ft Wayne (home of the popular Three
Rivers Festival raft race in July), and I've logged several good nights into
northern EU when a stratwarm was reported. And I've also heard nothing on
nights when a stratwarm was reported. That, in addition to IV3PRK's 160m
log, is why my general conclusion is they don't matter, and there's another
variable (in addition to the k-index) that affects 160m propagation.
Carl K9LA
--------------------------------------
R. Carl Luetzelschwab Mail Stop: 25-81
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Raytheon Systems Company
1010 Production Rd
Ft Wayne, IN 46808-4106
Phone: 219-429-4338 Fax: 219-429-6736
E-mail: rcluet@most.fw.hac.com
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