ARRL Propagation Bulletin ARLP007 (2010)

ARLP007 Propagation de K7RA

QST de W1AW  
Propagation Forecast Bulletin 7  ARLP007
From Tad Cook, K7RA
Seattle, WA  February 19, 2010
To all radio amateurs 

ARLP007 Propagation de K7RA

We've now observed sunspots continuously for the past 30 days,
certainly a turnaround from the quiet conditions of the past few
years.  In fact, in ten weeks we have seen only three days with no
sunspots, on December 25, January 6 and January 19.  This is a
little over 4% no-sunspot days, a nice contrast with all of 2009,
with over 71% days with no sunspots.

Sunspot group 1049 emerged on Wednesday, and it is growing.

The minimum non-zero sunspot number is 11.  This is because the
numbers are derived from the number of sunspot groups, plus areas
inside the groups.  Each group counts for 10, so the minimum sunspot
number is 11, and the minimum sunspot number for at least two
sunspot groups is 22.

In 2009 only 87 days (23.8%) had sunspot numbers greater than 11,
and 21 of those days were in December.  Only 43 days (11.8%) had a
sunspot number greater than 15 (14 of those in December), and only
26 days in 2009 had a sunspot number of 23 or more (none had 22).

Since the first of the year, average weekly sunspot numbers were
14.6, 26.4, 18.6, 28, 14.6, 43.3, and 38.7.

This weekend is the ARRL International CW DX Contest, and there is
every reason to expect continued good conditions.  Predicted
planetary A index for today, February 19 is 10, followed by 5 for
the next week.  Solar flux for February 19-25 is predicted at 85,
85, 84, 84, 82, 80 and 78.  Geophysical Institute Prague predicts
quiet to unsettled conditions for February 19, and quiet conditions
February 20-25.

The wonderful STEREO tool at
disappeared about a week ago, and hasn't been seen since.  Server
problems, I am told, but the folks at NASA who work on the STEREO
project say it is out of their hands.  They keep expecting it to
return in the next 24-48 hours, but it hasn't yet.

At you can see
current images from the program, and note that the end of that URL
is a date, which you can change to see images from different days.
We just don't get to see that marvelous and very useful spinning Sun

page also has links to data, but I don't pretend to know what much
of it means.  Next Thursday, February 25 images from the STEREO
spacecraft will achieve 88% coverage of the Sun.

Many emails have been coming in this week about a new application
for the iPhone that gives real-time views of the Sun from STEREO,
and will even alert users if a significant event is taking place.
It is called "3D Sun," and you can find out more about it at and also in an article at

Another propagation related iPhone app was released last year, which
you can peruse at,

We have some new links this week for those who like to monitor
ionospheric sounders, or ionosondes.

For an introduction, see  Check out for a geographic view of
ionosonde stations and access to their real time data.

Carl Luetzelschwab, K9LA sent a link to an article from 2007
summarizing what must be all the known predictions for the current
sunspot Cycle 24.  See it at and
note the last page for a colorful representation of the range of

There is a new article on helioseismology this week in Science
Daily.  See it at,

Angel Santana, WP3GW of Trujillo Alto, Puerto Rico had fun on PSK31
on February 15. At 1500 UTC he heard on 2 meters that 12 meters was
active.  Then he went to 15 meters where he heard Western Europe and
the Caribbean.  Many PSK31 signals on 20 meters, then at 1700 UTC
worked EI3GBS and 9H4N on 17 meters.

Angel wrote, "At 2000 UTC went to 10 meters and heard USA! (Absent
for some months.) Began to call on 28.465 and K4KV answered at 2012.
He told me he was listening via backscatter, and I told him my
antenna was pointing to Africa/Europe and he was booming in. Then
went to 40 meters at 2245 UTC and worked 9A3AGS from the island of
Brak. And heard the band so crowded we say here in Spanish, 'esta
Esplaya!' coined by Fernando, KP3AH."

Check out Angel's personalized page at QRZ.COM at,

Jim Puryear, N5TSP at EM00xf in Austin, Texas wrote, "On Feb. 13 at
0300Z I noted Es propagation from XE1 on 10 and 6 meters coming into
central Texas. Then heard VK2APG on 28.485 calling CQ and made a
quick QSO with signals about 55 each way. I imagine this may have
been an Es hop to XE1 followed by F2 to VK--a pleasant surprise for
a late evening on the upper end of HF. Now if we can just get this
happening on 6 meters."

Jeff Hartley, N8II of Shepherdstown, West Virginia has been excited
about increased solar activity and better conditions.  He asked for
a good site to get solar flux data.  The most immediate is straight
from the observatory in Penticton, British Columbia at

You will note there are three readings per day, and the one at local
noon (2000z) becomes the official solar flux number for the day.
Later it is rounded off and posted with the sunspot number at

Jeff sent this report yesterday, February 18:  "I feel we have
turned the tide on very low solar activity and now can expect low to
moderate activity consistently with daily good 17 and 15M openings
to EU from this area."

"I took the day off from radio Saturday, and Sunday February 14 it
didn't take long to realize something was up; at 1333Z I checked 15
meters to find lots of EU signals; I called E73XL and a UA4 running
QRP 1 watt called me as I was signing. We both QSY up and UA4HFD
went in the log first followed by the 1 watt station UA4CDV who was
S3.  Even during the good conditions on 15 during the CQWW phone
last October, there was little or no opening to UA4."

"So, after a breakfast break at 1358Z, I check 12 meters to find the
band just opening to EU. PY0FF was logged, then I called CQ. The
first QSOs were with HA and OK followed shortly by weak LA5YJ at
1416Z.  OQ5M was S9+, then at 1435Z 4Z4DX was logged S9 followed by
a very loud OZ8ABE. 9X0CW was S7 next. The band was in good shape
until after 1535Z when I went QRT."

"Monday was a day of strange conditions with obviously some solar
flare activity. For example, at 2217Z well after the normal opening,
I worked OH3SR on 17 meters and he went from S5 to S9, then back
again to S5 within about a minute; the QSO was probably via auroral
E. 15 meters was open well to EU all morning, but the remarkable
QSOs were with UX1UF and ER4DX (S9+) around 1650Z about 2 hours
after their sunset. Signals from western EU were booming in then. 12
meters was open well to the Caribbean/SA most all of the day and was
marginal to EU with only a few Is and EAs answering my CQs. 3B8DB
was S5 at 1543Z. TX4T was logged on 17 meter CW very early at 1612Z.
But 12 meters blew wide open to EU from 1730-1800Z with some
incredibly loud signals from western EU; the Belgians seemed to have
the sweet spot on the other end with a couple of them well over S9,
including ON7TZ and a couple of QRP stations, ON3VR and ON6AB S5-S7.
10 meters opened for about 45 minutes to the west coast around
1900Z, then around 1945Z TX4T was worked on 10 meter SSB and FO/N6JA
was logged at 2122 on 10 meter CW (both French Polynesia) followed
by very loud signals from LU and PY. PU2KLM was over S9 with just a
vertical and 100 watts on his end."

"Also of note was stateside propagation. I chase counties. Towards
sunset N4JT/M in LA was S9 or better on 20, 30, and 40 meters near
the same time. Also around 2300Z on 40 meters, everyone calling him
on the net from NY, PA and VA to MO + MN and farther was S9 or
better and N4JT was about 15 dB over S9. I've never heard 40 meters
that good for several years going back to near the peak of the last

"15 meters has been open to JA between 2230-2315Z quite a few days
and 17 meters open daily and longer."

Thanks Jeff.

Randy Crews, W7TJ of Spokane, Washington sent a URL for a site I'd
lost track of for some 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

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Sunspot numbers for February 11 through 17 were 64, 38, 37, 28, 27,
28, and 49 with a mean of 38.7. 10.7 cm flux was 94.2, 95.5, 94.1,
89.4, 87.6, 86.8, and 86.9 with a mean of 90.6. Estimated planetary
A indices were 5, 6, 3, 4, 14, 9 and 4 with a mean of 6.4. Estimated
mid-latitude A indices were 4, 4, 2, 3, 8, 11 and 2 with a mean of