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ARRL Propagation Bulletin ARLP052 (2005)

ARLP052 Propagation de K7RA

QST de W1AW  
Propagation Forecast Bulletin 52  ARLP052
From Tad Cook, K7RA
Seattle, WA  December 9, 2005
To all radio amateurs 

ARLP052 Propagation de K7RA

This weekend is the ARRL 10-Meter Contest. This year's contest, the
one for 2006 and perhaps 2007 will probably all have very few
sunspots, but as we've discussed in recent bulletins, sometimes 10
meters opens when we least expect it, even in the middle of the
night or very early morning hours.

Mark Madcharo, AB2IW in Schenectady, New York will be running QRP in
the contest this weekend and wants to remind us to check paths from
the northern to southern hemisphere, which at times may provide the
only long distance openings. Don't be afraid to call CQ on what
sounds like a dead band.

You can also check the beacons down in the area between 28.2-28.3
MHz (where most of them are, anyway) or the very useful NCDXF
beacons. A list of 10-meter beacons we provided recently is at The NCDXF beacon details are at and

One of the remarkable features of the NCDXF beacons is that the
timing is precisely controlled, so it is easy to tell where a weak
signal is coming from if you know what time it is, even if you can't
copy the call sign. Also, they step through several discrete power
levels, at 100 watts, 10 watts, 1 watt and 100 mW. Another nice
thing is that their network also covers the globe for 12 meters,
which can sometimes give a hint of good things to come if 10 meters
is not quite open yet.

Sunspot numbers and solar flux declined as sunspot 826 moved to the
edge of the visible solar disk. Sunspot numbers peaked after the
beginning of the month. Average sunspot numbers for the past week
(the first week of December) were almost 39 points above the
previous week, at 72.6. Geomagnetic conditions were very quiet for
the past few days. For this weekend, the predicted planetary A index
from December 9-12 is 7, 12, 10 and 5. Predicted solar flux for
today (December 9) is 85, and 80 is predicted for the following five

There is very little chance for disruptive solar flares this
weekend, although conditions are expected to be slightly unsettled
compared to the past few days. The College K index, measured in
Fairbanks, Alaska has been 0 for sixty hours straight at the time of
the writing of this bulletin, early Friday morning.

You can access an array of magnetometers in Alaska to compare
current to recent conditions at, The
measurements are in NanoTeslas, which are used to calculate the more
familiar K index, but you can get a good visual indication of
relative quiet or activity. Note that at this site you can vary the
time observed from the last 24 hours up to one month, vary the
scale, and include readings for up to 8 stations.

Geophysical Institute Prague predicts unsettled conditions for
December 9 and 10, quiet to unsettled December 11, and quiet
conditions December 12-15.

David Moore sent us a article about space storms and
observing upper atmosphere disturbances. You can read it at,

Back in December 1999, Propagation Forecast Bulletin ARLP052 for
that year (see it at noted that the end
of 1999 would end the 9th calendar year of writing this bulletin,
and that December was the 17th season the author performed as the
Grandfather (a non-dancer's role) in Pacific Northwest Ballet's
production of "The Nutcracker."

This year marks my 23rd season in the Nutcracker and December 2005
the end of the 15th calendar year writing the bulletin. When I began
work on the Nutcracker, I thought if I was lucky the role might last
a few years. With this bulletin, I thought my tenure would be just a
few weeks. Thanks to you, the readers, and the ballet, both have
been a blast!

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 and an explanation
of the numbers used in this bulletin see the ARRL Technical
Information Service propagation page at, An archive of past
bulletins is found at,

Sunspot numbers for December 1 through 7 were 79, 98, 75, 91, 85, 58
and 22 with a mean of 72.6. 10.7 cm flux was 98.2, 106.3, 101.3,
95.2, 91.7, 89.1, and 89, with a mean of 95.8. Estimated planetary A
indices were 13, 12, 11, 5, 2, 3 and 0 with a mean of 6.6. Estimated
mid-latitude A indices were 12, 10, 9, 3, 2, 2 and 1, with a mean of


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