krokus
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Propagation affects noticies (solar, volcanic, meteoric, etc...)
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Nov 19 06:52 UTC 2003 |
I got something in the mail today talking about the solar activity coming
our way again. I figured this would be a good reason to start another
item, for posting notification of events that can seriously affect the
propagation of the radio bands. (Obviously, most of these will be
solar activity.)
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krokus
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response 1 of 4:
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Nov 19 06:53 UTC 2003 |
From the Popular Communicatins mailing list:
From : Popularcom@aol.com
Reply-To : Popularcom@aol.com
To : Popcomm-L@popular-communications.com
Subject : [popcomm-l] More Flares And HUGH Sunspots Observed
Date : Tue, 18 Nov 2003 10:54:03 EST
THEY'RE BAAACK!
Power-house sunspot Regions 10486 (currently the record-holder for
producing the largest solar x-ray flare in recorded history) and 10488
(another X-class producing spot complex) are returning to the eastern solar
limb.
Later today (and possibly tommorrow as well), these regions will be
renumbered. For now, we will refer to their old designations: 10486 and 10488
(or simply, 486 and 488).
Region 488 (which led Region 486 by roughly one day) has appeared as a
very large sunspot complex with a large penumbral mass. Size often matters
when dealing with large solar flares. Region 486 is not yet visible, but a
large solar flare behind the limb of the Sun where Region 486 should be, was
observed a few hours ago. An impressive loop prominence system (LPS) was
observed in h-alpha from this location. Major solar flare activity is now
considered possible given the strength of this current limb event.
Region 501 (formerly known as Region 484 last month) has also increased
in activity over the last 48 hours, producing numerous smaller (but
significant) M-class flares. An event on 17 November was associated with a
coronal mass ejection that is directed at least partially Earthward. Impact
of that disturbance could happen near the mid UTC hours of 19 November (as
early as tonight for eastern North Americans). Its arrival could
herald enhanced levels of auroral activity for many dark-sky middle latitude
observers.
Region 501 also produced a second influential solar flare a few hours
ago (just prior to the large solar flare on the eastern limb) that will
almost certainly help prolong auroral activity into 21 November when the
associated coronal mass ejection reaches the Earth.
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krokus
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response 2 of 4:
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Nov 21 19:23 UTC 2003 |
Got another one, sounds like a bad week for HF work.
Again, from the Pop'Comm mailing list:
From our Propagation Corner columnist, Tomas Hood, NW7US:
A severe geomagnetic storm is in progress at this time. As I
write this bulletin, the planetary K index (Kp) is at 7. The
Aurora Index is at 10 (maximum). The Bz (horizontal component of
the Interplanetary Magnetic Field) is strongly negative (oriented
southward), at -55.1 nanoTeslas. This stormy geomagnetic activity
is causing strong ionospheric recombination, decreasing the
maximum usable frequencies on all radio link paths. HF propagation
at all latitudes is poor.
This geomagnetic storm is a result of the arrival and passage of a
coronal hole mass ejection from 18-XI-2003. The solar wind speed
increased from 430 km per second to 750 km per second, with a very
strongly negative horizontal IMF component. Whenever the Bz is
negative (whenever the horizontal IMF component is oriented
southward), the IMF combines with the magnetosphere in such a way
as to create geomagnetic disturbances and ionospheric storms.
Aurora is also a typical result of such interaction.
This geomagnetic storm is expected to continue through the end of
20-XI-2003. Additional CME arrivals may continue to keep the
geomagnetic activity high.
At 0747Z, 20-XI-2003, a flare peaked at M9.6, further causing
degradation of the HF propagation, on the sunlit area of the Earth.
Continued C, M, and possible X flares are possible today and for
the next week. The major sunspot groups from the end of October
and the beginning of November have and are returning into view,
increasing solar activity.
Today's HF propagation outlook is poor. While the 10.7-cm flux
is climbing, the continued geomagnetic storm will significantly
degrade higher frequency propagation. The moderate to major flare
activity expected will also degrade mid-HF frequencies. Nighttime
propagation on low to mid HF frequencies will also suffer, as the
E-layer will be significantly recombined, decreasing its MUF.
VHF propagation via Aurora, Aurora-E, and Trans-equitorial
propagation (TEP) will be fair to good. I welcome reports, if
any, of your success on VHF during this period.
More information as events warrant will be posted in follow-up
bulletins. Live information is ongoing at
http://prop.hfradio.org/ and a discussion is at
http://hfradio.org/forums/
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eprom
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response 3 of 4:
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Jun 18 13:59 UTC 2004 |
I woke to my radio playing evenscence, which is kinda wierd considering
I have it set to 104.1, the Grand Rapids NPR station. the 104.1 I was
now listening to was WLBC, a station down in Muncie, IN. SO either the
Grand Rapids station is having technical problems, or there is some good
ducting going on right now.
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