Hi Luke,
March and April (and September and October) are the months when
the interplanetary magnetic field (IMF) is twice as likely to be
oriented southwards (-Bz) than in June, July, December and January.
S outhward IMF orientation is far more significant than the intensity
of coronal hole high speed streams (CH HSS). CH HSS energy in
the solar wind very efficiently transfers into the earth's magnetosphere
and ionosphere when the IMF is oriented southwards for at least a
few hours. T he earth's magnetosphere does an excellent job repelling
almost all CH HSS energy w hen the IMF is oriented n orthwards (+ Bz)
or neutral (-Bz less than 5 nT).
Disturbed propagation will be much more extreme and much longer
lasting when coronal mass ejections (CMEs) occur more frequently,
likely starting next year. During the years near solar minimum the
southward orientation of the IMF only infrequently lasts for more than
two or three hours but when CMEs become more frequent the IMF
sometimes persists in a southward orientation for days! ugh...
By next year you'll be longing for the good old days of just a few
hours of disturbed propagation caused by southward IMF concurrent
with CH HSS.
73
Frank
W3LPL
----- Original Message -----
From: "List Mail" <mail10@barefoothorse.com.au>
To: "Bob Kile" <midnight18@cox.net>, "Topband" <topband@contesting.com>
Sent: Tuesday, March 30, 2021 11:22:05 PM
Subject: Re: Topband: W7 Propagation 3/29/2021
These Coronal Hole high speed solar winds seem to be quite relentless! I get
the impression that I’m more affected by the disturbances than those North of
me. I’m at 37 degrees South.
I’ve been on some mornings, looking for Europe CW contacts. There seems to be a
bare handful of ops on. I worked my first EA6 yesterday morning. Josep was
using only 100 watts! In our evenings, there are a bare handful of CW ops on in
NA too. Conditions that way have been very poor, when usually, the Equinox
gives us good openings.
As ever, we live in hope! There is no “Top Band Season” as far as I’m
concerned. I’m on every day.
73, Luke VK3HJ
Sent from Mail for Windows 10
From: Bob Kile
Sent: Wednesday, 31 March 2021 3:35 AM
To: Topband
Subject: Topband: W7 Propagation 3/29/2021
Out of the blue with continuous solar disruptions and high A and K
indexes an opening occurred last evening. A Index zero and K index less
than 1 the band was a bit noisy, typical of Spring time levels. Miracles
do happen.
I worked SM5EDX and SM3EVR from AZ QTH before I discovered my power
level was only 25W! OK1CF made it into the log as well. Heard but not
worked G3PQA, G3YRO and DL8LAS. Then the bell struck. At 04:00 UTC I
lost remote Internet connection for the rest of the evening. :(
160m the magic band....
Bob W7RH
--
W7RH DM35OJ
“Small is the number of people who see with their eyes and think with their
minds.” – Albert Einstein
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