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ARRL Propagation Bulletin ARLP054 (2009)

ARLP054 Propagation de K7RA

QST de W1AW  
Propagation Forecast Bulletin 54  ARLP054
From Tad Cook, K7RA
Seattle, WA  December 31, 2009
To all radio amateurs 

ARLP054 Propagation de K7RA

Here we are on the last day of the year, with finally some very
positive indicators for Cycle 24. Except for Christmas day, since
December 9 sunspots have been visible every day. Average daily
sunspot numbers for the week December 24-30 were 12.9, an 18.5 point
drop from the previous week, which was a 10.3 point rise from the
previous week, December 10-16.

Average daily solar flux dropped from 82.8 to 76.2 from the December
17-23 reporting week, but the December 30 forecast from the U.S. Air
Force predicts a solar flux value of 79 from December 31 to January
3, 80 for January 4-9, and 85 for January 10-18.  They also predict
a steady and stable planetary A index of five through February 13.
Geophysical Institute Prague predicts quiet for the first week of
January.  You can get an update on the Air Force/NOAA prediction
after 2100 UTC at,

Since December 26 we've been blessed with new sunspot group 1039,
which is now just past the zero degree meridian, referenced to
Earth.  This is the spot in the center of the solar image.  This is
the sixth new sunspot group to emerge in December.

After today we will know the three-month moving daily sunspot
average centered on November, and it looks close to the average
centered on August, 2007, which was 10.17.  The moving average has
not been above ten since then.  The daily average for the month of
December should be close to 15.7, the highest monthly average since
March, 2008.

A number of sharp-eyed readers caught the major gaffe in the last
bulletin, when I dozed off and with my fingers on autopilot I typed
Spring Equinox when I should have said Summer Solstice.  Needless to
say, Spring is not six months off.  The Vernal (Spring) Equinox is
only 79 days from today. Thanks to (in order of notification) N5UWY,
WE5I, KW6G, KF7FIU, W3DM, N0LNO, and WA3VKG for noticing and not
having too much fun at my expense.

Joe Reisert, W1JR, an exceptional low band DXer sent some comments
about the solar minimum.  I commented that the exceptionally quiet
conditions are remarkable, and may partially make up for a lack of
solar activity.  At least we aren't bothered by large flares.

Joe responded, "I really don't think the low bands are that improved
over times when the sunspots were there. Yes, it was nice to work
TX3A and K4M on 160 meters for new ones but I still can't get JT1CO
to hear me! Sometimes JAs spot me on 160 meters but no JAs call me!
Except for early last February when one morning I worked 7 JAs (!)
in a row starting at my sunrise (!), I haven't seen any really great
Asian openings. I guess I just have to hang in there. I did land
VK9XX on 80 near our sunset for number 341 about a month ago. That
was a real thrill as he was only working Europeans and somehow I
broke the pile up."

Rod Vorndam, K9ROD of Rye, Colorado wrote last week: "The past
couple of weeks have seen openings to Europe at sunrise on 20
meters. This Gray Line Effect has made for several strong contacts.
I worked I2OHO (Italy), ON5CD (Belgium), HB9RDE (Switzerland), and
received several others including OZ1IKY (Denmark) and S51ZZZ
(Slovenia). These are my first European contacts into the Western
part of the US."

Mark Lunday, WD4ELG of Greensboro, North Carolina has a nice blog
with observations on DX from his new QTH.  Read it at

Mark wrote, on Christmas Day: "One thing I have noticed recently
with the slight up tick in solar activity, is that 40 meters now
reminds me of 20 meters during the solar peak. Even during daylight,
there is DX open to somewhere on 40 in winter months. The exception
is high noon. But mornings and late afternoons have LOTS of activity
on 40."

"This afternoon, I copied HS0CZY/4 on 40 meters about an hour before
my sunset.  The last time I remember something like this was 1
January 2005 when I worked YB1A on 40 CW late in the afternoon."

"On Monday at 0100 local, I heard a fluttery signal RST 529, I copy
JA7DLE, call him twice, he gets my call, BAM he is in the log. I
have ONE JA QSO ALL-TIME on 80, and this is my SECOND EVER on 40.
This is with a single vertical and 100 watts.  What is neat about
this is that it happens at 0100 local while I can hear EU stations
599 AND South Cook Islands DXpedition 559. So I am copying Pacific,
JA, AND Europe at the same time.  When the Sun throws lemons, make
your own DX/lemonade."

"I heard 4S7NE on 40 CW at 2030 local, just after his sunrise.  I
have tried to hear Nelson since I worked him on 17 meters back in
2005, but I have never heard him since. Amazing!"

Thanks Mark.

Bob Doherty, K1VV of Lakeville, Massachusetts reminds us that
tonight is Straight Key Night!  Take a look at, and scroll down.

Jose Nunes, CT1BOH of Lisbon, Portugal (see sent some fascinating material
that he posted to the cq-contest email list at,
titled "Listen to what happens when a X4.0 Solar Flare hits your
contest operation."  He referred to K9LA's article, "Solar Flares at
ZF2RR," which you can read at,

Jose writes, "It just happens that while operating P40E during the
2000 CQWW CW Contest, I was recording the event. And I still
remember the black-out that followed the big X4.0 Solar Flare. I
thought it would be interesting to share the story and the audio
clip of the impact of the solar flare."

"First take a look at the Goes X-ray Flux (5 minute data) on the 25
and 26 November 2002:
I marked with an arrow the big solar X4.0 flare that occurred at
16:38 on 26 November, Sunday of the contest. P40E was QRV on 21 MHz
(21050 kHz).  In the 40 minutes before the Solar Flare impacted P40E
operation, 16:00 - 16:39, I had worked 107 QSOs at a rate of 160.5
QSOs per hour. In the 20 minutes after the Solar Flare impacted P40E
operation 16:40 - 16:59 first there was a 7 minute black-out and
then I managed to work 10 QSOs at a rate of 30 QSOs per hour."

"Very interesting is the surge of noise right after the Solar Flare
until almost total black-out of the bands and during the 7 minute
black-out. You will listen to a vanishing pile-up, to a dead band,
and then the recovery of activity."

"You can check P40E log at
to follow audio clip from 16:36z until 17:02z."

"Listen to the 26 minute audio clip at and note this was an SO2R
operation so you should use headphones. You will listen on the left
ear to radio 1 (RUN radio) on 21 MHz and right ear to radio 2 (S&P
radio) on 28 MHz before the QSY to 10."

Fascinating!  Thanks so much, Jose.

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 December 24 through 30 were 11, 0, 13, 17, 17,
17, and 15 with a mean of 12.9. 10.7 cm flux was 77.1, 76, 75.9,
76.8, 75.8, 75.1, and 76.9 with a mean of 76.2. Estimated planetary
A indices were 2, 2, 3, 2, 1, 0 and 0 with a mean of 1.4. Estimated
mid-latitude A indices were 1, 3, 2, 1, 1, 0 and 0 with a mean of


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