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ARRL Propagation Bulletin ARLP053 (2008)

ARLP053 Propagation de K7RA

QST de W1AW  
Propagation Forecast Bulletin 53  ARLP053
From Tad Cook, K7RA
Seattle, WA  December 19, 2008
To all radio amateurs 

ARLP053 Propagation de K7RA

Last week's sunspot group was only visible for three days, December
10-12.  The average daily sunspot number for all of 2007 was 12.8,
and if we see no sunspots for the rest of 2008, the average for this
year will be 4.7.  By comparison, the yearly averages of daily
sunspot numbers during the last solar minimum in 1995-1997 were
28.7, 13.2 and 30.7.  This solar minimum is much lower than the one
about 12 years ago.

Geomagnetic conditions have been stable and quiet this week, very
nice for those lower HF frequencies during the long nights.  As you
can see when checking the site,, there have
been many very quiet geomagnetic periods over the past few months.
That table is based on the calendar quarter, so check for the previous 30
days if you are reading this later than the end of 2008, only 12
days after this is written.

The daily A index (a linear scale, calculated from the eight daily K
index readings, which are on a logarithmic scale) gives an
interesting comparison to the last solar minimum.  We can check
those weekly averages beginning with the October 11, 1996
Propagation Forecast Bulletin, when we began presenting the
planetary A index at the suggestion of Robert Wood, WB5CRG (now
W5AJ) of Midland, Texas.

Go to and compare the
weekly averages with current averages at, and you can see that
during all those weeks of zero sunspots, geomagnetic activity was
much higher.  It is also interesting to note how quickly sunspots
returned toward the end of 1996, after those long weeks of no spots.

The outlook from USAF/NOAA shows solar flux below 70 through
December 25, then at 70 from December 26 to January 8.  Perhaps
during this period we may see more sunspots.  The same prediction
shows a planetary A index of 5, except for December 22-23 when it
rises to 10, then 8, and December 31 to January 2, with a planetary
A index of 8, 10, and 10.  Otherwise, all could be quiet.

Geophysical Institute Prague predicts quiet conditions for December
19-21, unsettled December 22-23, quiet to unsettled December 24, and
quiet again on December 25.

The 2008 Winter Solstice officially occurs in the Northern
Hemisphere at 1204z on December 21.  This is during darkness on the
West Coast of North America, where I am, so my Saturday night
through Sunday morning should be the longest night of the year.
This far north (Seattle) the Sun will set at 4:20 PM (0020z Sunday)
on Saturday night and rise at 7:55 AM (1555z) on Sunday, December
21. This is 15 hours and 35 minutes from sunset to sunrise, nearly
two hours longer than the same night in South Florida, and almost
two and a half hours longer than the same night on the southern tip
of the island of Hawaii.  Tierra Del Fuego, at the southern end of
South America will have a very short night this weekend, about six
hours and forty minutes from sunset to sunrise as it enters the
Southern Hemisphere's summer season.

With all of these quiet days, there is still fun to be had and
things to explore on HF.  Two weeks ago on December 5, Chuck Hooker,
VE3CQH of Orangeville, Ontario reported, "The low sunspot cycle
doesn't seem to affect me and Bill, K4KSR (of Yorktown, Virginia).
He added to his DX total during last weekend's contest (CQ World
Wide CW DX Contest), using a K1 transceiver, and he and I
communicated during our first sked (and my first QSO) in over a
year, earlier this week on 40 meters.  I called; he answered."

He continues, "Bill uses 5 watts or (usually) less to a hidden
antenna.  I applied 1.2 watts from a crystal-controlled Little Joe
through a home-brew antenna tuner to a G5RV about 20 feet up (but
downhill from the shack).  Bill gave me a 579 at 1900 GMT."

In last weekend's 10 meter contest we still saw activity, despite
the fading sunspots.  Dan Eskenazi, K7SS of Seattle, Washington
reported some scattered openings on Saturday to the south and
southwest, and some nice sporadic-E propagation into Colorado, and
double-hop propagation further east.

Terry Oldham, KH6MT of Grand Island, Florida reported hearing good
signals from the east coast and into Ohio, Michigan, Arkansas and
Louisiana, but not to Texas.

Vic Woodling, WB4SLM of Centerville, Georgia said the 10 meter
propagation was unique, and while he put a small effort into the
contest, he also said "there was something for everyone."

Vic reported, "Friday night 13 Dec, ground wave was awesome. Can't
say as to why, but could very easily work stations 200 to 300 miles.
Found conditions close to what one will see on 6 meters. I decided
to check 160 after about an hour from the start of the 10 meter
contest and logged UT3UA amongst others in EU. Went back to 10
meters at 0321 and had some very unusual prop into the NE. It may
have been Es, but let me explain: the conditions sounded like Meteor
Scatter with an E coupling.  CW signals were great. Hearing very
strong bursts with long decay and the residual was there for several
minutes. For example, K1ZZ was one call 100 watts and I heard him
many times over the next few hours in and out of the noise. Around
0400z band shifted to the 0's. I stayed up until about 0530z and
continued working 2's and 3's. Saturday afternoon 13 Dec some Es to
8 and 9 land."

Vic continues, "Sunday 14 Dec, between 0100z to about 0200z very
strong ground wave again but not as long a distance as the night
before. 10 meter Es to W0SD, but the E was sporadic. Checked 160 and
logged OK2PAY, SM5EDX, UR0MC, UX1UX and copy but not work EL2DX.
QRT at 0400z, but back on at 1624z and the band was open Es to all
call areas.  Didn't have to move the antenna, very strong signals.
Around 2015z the Papa Yellows (Brazil) appeared -- musta been every
PY in the country on along with OA (Peru), then a shift at 2047z to
LU9 land (southern tip of Argentina). Signals were in reality 5x5 to
5x7 (disregarding the usual exchange!), but no problems working them
very quickly. In the middle of the DX, stations in North Florida and
South Florida suddenly appeared with 20+9 signals (very short skip).
Went over to 6 meters quickly and got a partial on WP4 and some NE
stations but not staying as I wanted the DX on 10.  2120z the band
shifted again and into the scatter mode. I worked some more GA, AL,
SC and NC stations on groundwave and dropped up to 160 after the
0000z hour."

He goes on to say, "Monday, 15 Dec, after the 10 meter contest was
over, 160 was great for us with a dipole and couple hundred watts.
Logged RK3AWL and his signals were an honest 599 on the meter; mine
weren't so good at 449.  Worked GW3YDX, ES5QX, LA5HE, SM2LIY and
OH2BO, I'm first to hear him (Vic isn't clear which one), but with
his "QRZ?" to my call, it created an orange glow of EMP radiation
out of the NE, thus prohibited me from making the contact".

He ends with, "Overall I thought the 10 meter band was a pleasant
surprise. I wasn't expecting much, but what I'll call meteor scatter
with residual really got me going, and for me it's always been the
propagation and the wonder of it that has kept me in radio. Anyone
can buy a kit, have the biggest and best, but it's the absolute
wonder of radio wave propagation which keeps the headsets on."

Thanks, Vic!  There is much more to report, and this is running very
late.  I am between snowstorms in Seattle, and it is almost noon in
Newington Connecticut where a "blizzard" is about to blow in, so I
must put this to bed.  Expect to read more about meteor scatter in
the next bulletin, a hole in the terrestrial magnetic field, and a
thin ionosphere, which may come out as an extra on Monday, December
22 in addition to the following Friday bulletin on December 26.

Stay warm and safe!

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 11 through 17 were 12, 14, 0, 0, 0, 0,
and 0 with a mean of 3.7.  10.7 cm flux was 70.2, 71, 69.7, 68.8,
68.9, 69.4, and 68.8 with a mean of 69.5.  Estimated planetary A
indices were 3, 2, 1, 0, 1, 4 and 5 with a mean of 2.3.  Estimated
mid-latitude A indices were 4, 2, 1, 1, 1, 4 and 3 with a mean of


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