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ARRL Propagation Bulletin ARLP001 (2010)

ARLP001 Propagation de K7RA

QST de W1AW  
Propagation Forecast Bulletin 1  ARLP001
From Tad Cook, K7RA
Seattle, WA  January 8, 2010
To all radio amateurs 

ARLP001 Propagation de K7RA

Recent sunspot activity is increasing, and the numbers bear this

The average daily sunspot number for 2009 was 5.  The average for
2008 was 4.7.  Not much difference in those numbers, but those are
for calendar years, and the trend toward the end of 2009 was
increasing sunspot activity.

Average daily sunspot numbers for 1999-2009 were 136.3, 173, 170.3,
176.6, 109.2, 68.6, 48.9, 26.1, 12.8, 4.7 and 5.

A few years ago we began recording a moving average of daily sunspot
numbers based on three calendar months, to help us spot a sunspot
cycle bottom.  Perhaps this would give us a more immediate
indication than smoothed sunspot numbers, which use a whole year of

Because we now have all of the sunspot numbers for December, we can
calculate the three month average centered on November 2009, 10.16,
which is the highest it has been since August 2007 when it was
10.17.  We will know the average centered on December at the end of

Over the past couple of years it looked like the moving average
bottomed out several times.  In late 2007 it appeared we hit bottom
when the three-month average centered on October dropped to 3.  Then
the average rose, and was in the range of 8.23 to 8.89 centered on
December 2007 through April 2008.  The average declined again, and
hit 1.1 in August 2008.  In September through November it moved to
2.5, 4.52 and 4.39, then declined to a new minimum of 1.5 in March,
2009.  From there it rose, stalled and rose dramatically when from
April through November 2009 it was 2.01, 4.23, 5.2, 4, 4, 4.64, 7.1
and 10.163.  The average daily sunspot number for just the month of
December was 15.7, which is a good trend, 5.54 points higher than
the 3-month average.

On Wednesday of this week the sunspot number was zero, but it rose
to 15 on Thursday with the appearance of new sunspot group 1040.
Over the weekend sunspot groups 1036 and 1038 are due to return,
although we don't know yet if they are still powerful enough to be
classed as sunspots.

The latest prediction is for geomagnetic conditions to remain quiet,
with the anticipated planetary A index at 5.  But looking at recent
predictions from USAF/NOAA, that value is probably a maximum, since
they have predicted that value almost every day for months, and
actual numbers were better (lower).  Check the table at and note that the
planetary A index hasn't gone as high as 5, and as of Friday morning
the last time it rose to 4 was December 14.

The same prediction shows solar flux at 79 for today (January 8), 80
on January 9-10, 82 on January 11, 84 on January 12, and 86 for
January 13-15.

Regarding recent conditions, from last week, Jeff Hartley, N8II of
Shepherdstown, West Virginia said in a New Years Eve email that
conditions seemed poorer on the higher bands (17 meters and up) than
the solar activity would suggest.

But then Jeff saw better conditions on lower frequencies.  He
writes, "Last night, the 30th was exceptional on 30, 80, and 160.
Several loud longpath JAs were worked on 30M, I tried 20M longpath
to no avail around 2320Z. Then signals from northern EU and other EU
were booming in on 160 from 0020-0130Z, I caught TF3SG on SSB. All
of the EUs heard on 80 at the same time were loud, and 4S7NE was
about S6-7 on 80 CW around 0120Z near his sunrise, attracting a

Last week we had an interesting email exchange with Jerry Spring,
VE6CNU of Calgary, Alberta, and comments from Carl Luetzelschwab,
K9LA, when I passed Jerry's email on to him.

Jerry thinks that HF conditions are poorer than expected, given the
solar activity.  He feels that conditions have not improved, and
wonders if there needs to be a certain threshold of activity, enough
to "kick-start" the F layers of the ionosphere.

Carl's comment was that we really haven't seen much sunspot
activity, enough to raise the MUF (Maximum Usable Frequency).  Carl
analyzed ionosonde data from Wallops Island in Virginia from last
August, and attached a graph representing the rise and fall of MUF
from day to day.  To see it, go to the web site

Carl wrote, "It shows the day-to-day variation of the F2 region MUF
over the Wallops Island ionosonde assuming it's the mid point of a
3000 km hop. Note that the MUF varies from a low of 11.6 MHz to a
high of 21.5 MHz - and to reiterate, this is with zero sunspots and
no change in solar flux.  Thus there are other factors that
ultimately determine the ionization - and these are geomagnetic
field activity and events in the lower atmosphere coupling up to the
ionosphere.  Surprisingly the day-to-day variation of the F2 region
is more due to these two factors than a small change in sunspots or
solar flux.  In fact, these two factors generally mask any small
increase in sunspots and solar flux."

Carl emphasized that only when sunspot activity rises significantly
will we see any long term improvements.  When we notice an
improvement in propagation, it may be due to other factors,
including seasonal changes.

Don't miss Carl's personal web site, a great resource devoted to
propagation at  He writes the
excellent monthly propagation column for WorldRadio Online, with a
new issue on the twentieth of each month, at  Note on that page
there is a link on the left to back issues starting with February

Tom Russell, N4KG of Harvest, Alabama lives for 160 and 80 meters.
He has an impressive array of antenna arrays at his place in the
woods west of Huntsville, including large ground plane antennas for
80 and 160, inverted L for 160, and dipoles on 80.  In fact, I was
just admiring his antennas, not from his photos, but publicly
available aerial images.  I went to and clicked
on Maps, then entered his address and ZIP code from his license
record.  He is actually west of the location that you land on, at
the end of a road.  Click on Aerial, then Bird's Eye, and note you
can click on vantage points from four directions, and can also zoom
in.  Look for multiple telltale Yagis in the woods.

Tom tells us that November and December had some fantastic 160 and
80 meter conditions, and he sent a long log listing of contacts in
Russia and Northern Europe from December 11-13, most on December 12
and most on 160 meters.  He notes more shortpath UA9s in two months
than in 30 years operating in Northern Alabama.  He says "These
Russian openings are not daily events by any means but there have
been (and continue to be) several very good nights (and mornings).
My friend N4NO (PhD in electromagnetic Field Theory and
Communications and very active DXer) suggested that these openings
are the result of historically low geomagnetic activity, a "seminal

Among his contacts over those days on 160 (mostly CW) were 4O3A,
EI2CN, ES2DJ, LA5HE, LY2J, LZ1ANA (S9++), RA0ALM (Zone 18, just

On 80 meters he worked RA4CC, RK3ER, SM4OTI (S9+), TF3SG (S9 SSB),
UA3TCJ, UA4HBW, UA4LY, UA9FMZ, UA9YAB, UU9DX, and UX4UU.  At the end
of it all, his amplifier died on December 13 and then he worked
RA0ALM, RA1AOB and UA3TCJ barefoot.

Tom reported on January 2 that "RZ0AF has been camping out on 160
and 80 Meters (3521), morning and night, around 1200 to 1300Z and
Friday evening from 2300Z to 0400Z, well past his sunrise which is
around 0200Z. He is located in Krasnoyarsk, about 300 miles north of
the NW border with JT, in Zone 18.  Is there a Big 160M station in
UA0Y (Zone 23 - my last needed Zone on 160M)?"

"UA9MA has also been active on 160 and 80M from Omsk in the SE
corner of Zone 17, peaking 569 on 3524 at 0342Z last night (Jan 2 in
GMT).  UA9KAA was running NA on 1823 (up 1) from 0500 to 0600Z,
peaking 569 at times.  He is in Northern Siberia in Zone 17. RX4HZ
was 599+ on 40M with a little help from his 4L Quad at 30M high at

The STEREO Mission has been a
tremendous asset, and this year is expected to move into a position
which allows us to see magnetic activity on the whole Sun.  This
weekend, on January 9 at 0836z the two satellites will be in
position to see 87% of the Sun, with the invisible spot on the far
side exactly 13%.  88% coverage (with 12% invisible) will be
achieved at 0611z on February 25, 2010.

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 31 through January 6 were 16, 16, 22,
20, 15, 13, and 0 with a mean of 14.6. 10.7 cm flux was 79.9, 75.2,
78, 76.4, 73, 76.8, and 77.3 with a mean of 76.7. Estimated
planetary A indices were 1, 1, 0, 3, 2, 1 and 1 with a mean of 1.3.
Estimated mid-latitude A indices were 0, 2, 1, 3, 1, 1 and 0 with a
mean of 1.1.


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