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Seattle, WA  September 25, 2009
To all radio amateurs

SB PROP ARL ARLP039
ARLP039 Propagation de K7RA

This week we had a double-dose of good news.  Right at the time of
the Autumnal Equinox, on Tuesday, September 22, sunspot 1026, a new
Cycle 24 sunspot, came into view over the Sun's eastern horizon.  We
watched this emerge a week ago on the Sun's far side via the STEREO
project (see http://stereo.gsfc.nasa.gov/).

STEREO is a fantastic tool, because it gives us all a live view of
nearly the whole Sun, and it displays very recent images.  It turns
out that images from each craft--the ahead (leading earth in its
orbit) and the behind (trailing earth in its orbit) satellite--are
updated approximately every 15 minutes!  No more guessing about
activity on the other side of the Sun, because we can see it live in
animated form based on real time data.

On that animated Sun display you can see there are longitude lines
every 30 degrees.  Since there are twelve of them, and a rotation of
the Sun takes approximately 27.5 days (it varies by latitude), then
on average it takes about .0764 days (1 hour, 50 minutes) for the
Sun's rotation to progress one degree longitude.  Therefore, when we
saw the sunspot at -120 degrees longitude, we could estimate that it
would take about 2.2917 days (2 days and 7 hours) for the spot to
reach the Sun's eastern horizon (at -90 degrees) and first become
visible.

On Monday the daily sunspot number was 11, then on Tuesday and
Wednesday a second Cycle 24 spot (number 1027) emerged in the Sun's
Northern Hemisphere.  Tuesday's daily sunspot number rose to 26,
then on Wednesday it was 31 as the area of the spots grew.  On
Thursday the sunspot number was 32.  From Monday to Tuesday the
total sunspot area increased by seven times, then on Wednesday it
doubled, then on Thursday rose about 29% over Wednesday's area.  You
can see the sunspot numbers, solar flux and sunspot area for each
day at, http://www.swpc.noaa.gov/ftpdir/indices/DSD.txt.

Checking http://www.swpc.noaa.gov/ftpdir/indices/DGD.txt shows us
that geomagnetic indices are extremely quiet and stable, so I
suppose there are three pieces of great propagation news this week.
Both sunspots have moved into their maximum geo-effective position
(around zero degrees longitude, in the center of the solar disc as
viewed from Earth), led by sunspot 1027.

The current prediction from NOAA/USAF is for continued quiet
conditions today with a planetary A index of 5, then on Saturday
some unsettled conditions and a planetary A index of 12.  It drops
to 8 on Sunday, then back to 5 for the foreseeable future.  Solar
flux is expected to continue at about the same level through the
first few days of October.

Geophysical Institute Prague has a similar prediction for
geomagnetic values, quiet to unsettled September 25, unsettled
September 26, quiet to unsettled September 27, and quiet conditions
September 28 through October 1.

Ken Tata, K1KT of Warwick, Rhode Island (grid square FN41gs) reports
that the Fall 144 MHz Sprint saw some great activity along the East
Coast.  This is sponsored by the Southeastern VHF Society
(http://www.svhfs.org/) and lasted for just four hours, from 7:00 PM
to 11:00 PM local time, on Monday, September 21.

Ken wrote, "From Rhode Island the band was open from at least
central Virginia to southern Nova Scotia. Overall, signals were
stable with shallow, slow QSB. This was perhaps the most active 2
meter contest I've seen. At 8 PM local time it sounded like an HF
contest!"

Tim Hickman, N3JON of Timonium (Baltimore area), Maryland said
"Propagation is up!" after he worked VK4MA long path on September 23
at 2137z.  Tim was running barefoot with a small 2-element multi
band beam, and received an S5 signal report.  Unfortunately, he
didn't say what band he was using, but I will bet it was 20 meters.

K4WY, KI4BXN and others tipped us off to a fascinating new story
about solar wind during the cycle minimum.  Dr. Sarah Gibson, lead
scientist on the study, found that solar wind may be much more
active during cycle minima than previously thought.  See the story
at, http://tinyurl.com/ndlffo, http://tinyurl.com/kw32nv and
http://tinyurl.com/y8n6old.

This weekend is the CQ World Wide DX RTTY Contest, and FT5GA, the
Glorioso DXpedition will be active.

With the heightened solar activity, here are some rough propagation
estimates for the path to Glorioso Island this weekend, which is off
the East Coast of Africa, northwest of Madagascar.