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ARRL Propagation Bulletin ARLP052 (2001)

ARLP052 Propagation de K7VVV

QST de W1AW  
Propagation Forecast Bulletin 52  ARLP052
From Tad Cook, K7VVV
Seattle, WA  December 7, 2001
To all radio amateurs 

ARLP052 Propagation de K7VVV

This has been a quiet week with no geomagnetic disturbances. Each
day's planetary A indices have been in the single digits, indicating
stable conditions without the high absorption of HF radio signals
associated with solar coronal holes and flares.

Note that on Monday, November 26, an extra propagation bulletin
(number ARLP051) was released, which corrected a solar flux number
from the previous week. Prior to ten years ago, W1HDQ wrote this
bulletin on Sundays.

Since then this bulletin has been published on Fridays, to give
amateur radio operators information in advance of the weekend. From
time to time we will put out an extra bulletin on Monday when
warranted by updated propagation and solar news.

Average sunspot numbers were up over 84 points, and average solar
flux rose by nearly 49 points. Solar flux has probably peaked for
the short term in the past few days. For this weekend, Friday
through Monday, solar flux is predicted at 225, 225, 220 and 210.
Planetary A indices are expected at 8, 8, 15 and 15.

The rising A index is possible because of sunspot 9727, currently
moving toward the center of the visible solar disk with a complex
magnetic field harboring the possibility for solar flares.

Average daily solar flux values for November were up slightly from
the previous month, and were a fairly high monthly value for the
year. Average daily solar flux for January through November was
166.6, 147.2, 177.7, 178.2, 148.7, 173.7, 131.3, 163.1, 233.8, 208.1
and 212.7.

Holographic images of the sun's far side show no substantial
sunspots. Barring any emerging activity, the next short term minimum
in solar flux is expected from December 16-20.

This weekend is the ARRL 160-Meter Contest. The following weekend is
the ARRL 10-Meter Contest. Conditions should be good for the
160-Meter test, barring any geomagnetic upset. The 10-Meter Contest
seems to be around a lull in predicted sunspot/solar flux activity,
but we should have an update next week.

Recently 6-meter operators have been working a great deal of DX via
F2 layer propagation. K7MCX in Seattle wrote that on December 4 at
2342z he worked JA7BZU on 6-meters. When he checked his log, he
found that his last QSO with this station was exactly 12 years
earlier at 2350z on December 4, 1989. This was at the peak of the
previous sunspot cycle. Then 23 minutes later at 0005z on December 5
he worked JO1MWX, a station he also worked on 6-meters on December
5, 1989.

Sunspot numbers for November 29 through December 5 were 204, 158,
208, 271, 230, 214 and 260 with a mean of 220.7. 10.7 cm flux was
216.4, 225.8, 221.3, 245, 235, 233.3 and 237, with a mean of 230.5,
and estimated planetary A indices were 3, 3, 7, 4, 7, 6 and 8 with a
mean of 5.4.


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