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ARRL Propagation Bulletin ARLP012 (2009)

ARLP012 Propagation de K7RA

QST de W1AW  
Propagation Forecast Bulletin 12  ARLP012
From Tad Cook, K7RA
Seattle, WA  March 20, 2009
To all radio amateurs 

ARLP012 Propagation de K7RA

This reporting week (March 12-18) there were no sunspots, but we saw
a couple of promising magnetic anomalies which faded away before
ever emerging as sunspots.

On Saturday, March 14, reported (see
a sunspot which might have been emerging south of the solar equator.

In addition to displaying an image from the SOHO/MDI (Michelson
Doppler Imager) project, provided a link to images
from Matthias Juergens in Germany.  (See for the

Matthias identified the images as evidence of "small flare activity"
in the southeast.

Also see an image on from Pete Lawrence, in West
Sussex UK.  (See for the

Note the image in the first link shows the possible
sunspot in the lower left quadrant of the visible solar disk, which
according to terrestrial mapping conventions would be the southwest
quadrant.  Why is the solar convention opposite?  I believe it is
based on a mirror image of the earthly convention.

Instead of imagining yourself in space, looking down at the Earth
with west on your left and east on your right, and then applying the
same convention if facing the Sun, instead look at the Sun from an
earthbound perspective.

Imagine a sunny day, and you are lying flat on a lawn, facing the
Sun, with your body oriented so that your head is toward the north
and feet toward south.  Without actually looking at the Sun, your
right side would be pointing west, and if you raise your right arm
to point to the right side of the Sun, according to convention that
is also the west.

So sunspots travel across the Sun (relative to Earth) from left to
right, from east to west.

On Sunday, March 15, reported a blank Sun at,,
but that "two proto-sunspots" were visible near the Sun's equator.
But the next day, and all week the Sun remained blank.  Solar flux
has been quite low also.

If you check
for daily forecasts, you will see that every day the solar flux
prediction has been a solid and unchanging 70 for the following 45
days.  But solar flux values have actually declined slightly over
the past few weeks.  As reported in this bulletin, the weekly
average solar flux ending on Wednesdays for the period beginning
February 19 and ending March 18 was 70.2, 69.5, 69 and 68.6.

If you check the latest 45-day forecast, which at the time of the
writing of this bulletin was March 19, you will see that the
predicted planetary A index for March 20-21 is 8, followed by a
slightly quieter level of 5.  The next moderate geomagnetic
disturbance is expected April 9-10, with planetary A index of 15 and

By the time you read this, the Vernal Equinox has passed and it is
Spring in the Northern Hemisphere.  The equinox is early on March 20
for much of the Western Hemisphere, at 1144z, which is 04:44 PDT and
07:44 EDT. This is a popular time of year for fans of HF
propagation, with the Southern Hemisphere moving into the fall
season, and bathed in sunlight equal to the Northern Hemisphere.

Al Lorona, W6LX of Arcadia, California asked about transitions from
one solar cycle to the next, and what the overlap was like.  If we
want to take a look at the last transition, from Cycle 22 to Cycle
23, you can inspect old copies of this bulletin in 1996, which was
the last solar minimum.  The archive is at and just click on Show Older
Bulletins, then Propagation for 1996.  You can see the weekly
averages, and in the Fall of that year there were weeks of no
sunspots.  But in 1997 you can see the weekly averages rose
substantially.  Such is not the case right now.

Looking back to the ARRL International DX Contest, SSB weekend, Jeff
Hartley, N8II of Shepherdstown, West Virginia wrote on March 7:
"There were surprisingly good condx at least on 20M in the few hours
I've operated in the ARRL DX test. On 20M, at the start, the band
was open fairly well to JA and KL7RA was loud. J5UAG answered a CQ,
and South America up to as far north as Cuba was loud, but by 2335Z
the PYs and LUs were fading out here in favor of areas farther west
and by 2355Z almost all stations to the south were gone. But, KH6
was loud. 40 was open well only to southern and western EU at 01Z.
At 1515Z, I started tuning across 15M which was only open to the
south, but the opening kept improving as I tuned up the band with
Caribbean stations becoming loud. I worked as far north as KP2M and
FS5KA. V48M who was S5 and not workable thru his pile-up was S9 and
easy 10 minutes later. P40A running 100W was the loudest station I
heard about 20 db over S9."

John Coleman, K5JVC of Oklahoma City worked the same DX contest,
using 5 watts and a 31 foot vertical on 15 meters, which I guess
would be about 5/8 wavelength on that band.  On Saturday, March 7
beginning at 1335z he worked HI3K, VP5H, 6Y1V, HI3TEJ, VP2E, LT0H,
LU2QC, P40A, KP2M, WP4U, PJ4G, and VP8KF (The Falklands were LOUD!)
with the last at 1938z.  On Sunday he worked (starting at 1518z)
(Europe!), and ZF2AM.  CS2C was at 1934z and ZF2AM at 2146z.

John wrote, "All stations were ebbing and flowing rapidly.  I would
wait a few minutes to see if where their signal was peaking over the
course of 3-5 minutes and if they were peaking above S2 I would
pounce during the peak.  Most peaks only lasted 10-20 seconds and
then they were back in the noise."

Harvey Moskowitz, W2YWC of Livingston, New Jersey wrote, "I am
working on 5 Band DXCC with only one contact needed for 10 meters to
complete the cycle.  I check 10 meters periodically daily and the DX
websites, as well. Sunday, March 8 openings to SA were apparent and
I worked OA4SS, Lima, loud and strong for number 100!  Also many
signals from Brazil and Argentina. (3 element beam and running 100
watts!) U never know."

George Hall, W4BUW of Taylors, South Carolina also sent a report on
10 meter activity on March 8.  He said he didn't spend much time on
10 meters, but did work OA4SS at 2106z with S9 signals, and LU7DAG
at 2109, also S9.  He heard many other stations on 10 meters, but
didn't bother to work them.  Like several people who wrote this
week, he thinks that may people will tune into a quiet band, and
because they don't call CQ, they never know that it was actually
open, and think the band must be dead.

Brian Webb, KD6NRP who I believe is in Ventura County, California
wrote, "It's a good thing I read last week's propagation bulletin.
On Saturday, March 14, I recalled that your propagation bulletin
mentioned recent 10-meter openings between the U.S. and South
America. At about 2200 UTC I decided to give 10M a try. I tuned
around and found a CW station calling CQ. I answered and
subsequently had a QSO with KH6ZM on Hawaii's big island. What a
pleasant surprise! Although I have worked several stations on
10-meters via E-skip, this was my first long-range contact on that

Brian has a very interesting web site,
which has info on launches from Vandenberg Air Force Base.

I've noticed that sometimes I can see the antennas of readers who
write in to the bulletin, via aerial photos at  Just look up the street address online at or and enter it with the
ZIP code on the page.  On many locations, an option called
"Bird's eye" will appear.  Click on this option and instead of a
satellite photo, you can see a high resolution aerial photo taken
from a low flying plane.  In the upper left you can use + to zoom
in, and if you select another direction (it defaults to north), you
don't just turn the image, but you actually see a different photo
from a different perspective, often taken on a different day with
different lighting conditions.  For example, enter 225 Main St,
06111 for a view of W1AW.

Finally, Art Jackson, KA5DWI of North Richland Hills, Texas has an
interesting and useful document on seasonal sporadic-E propagation,
which will probably increase next month.  Read it at,  This looks like it
perhaps could be an update to a similar document mentioned in
Propagation Forecast Bulletin ARLP018 from last year, which is no
longer available at the URL mentioned at that time.

If you would like to make a comment or have a tip for our readers,
email the author at,

For more information concerning radio propagation, see the ARRL
Technical Information Service web page at,  For a detailed
explanation of the numbers used in this bulletin, see  An archive of past
propagation bulletins is at

Monthly propagation charts between four USA regions and twelve
overseas locations are at

Instructions for starting or ending email distribution of this
bulletin are at

Sunspot numbers for March 12 through 18 were 0, 0, 0, 0, 0, 0, and 0
with a mean of 0.  10.7 cm flux was 68.7, 68.2, 68.5, 68.4, 69.4,
68.8, and 68.4 with a mean of 68.6.  Estimated planetary A indices
were 6, 16, 9, 7, 5, 3 and 1 with a mean of 6.7.  Estimated
mid-latitude A indices were 6, 10, 7, 5, 4, 3 and 0 with a mean of


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