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ARRL Propagation Bulletin ARLP051 (1996)

ARLP051 Propagation de KT7H

Propagation Forecast Bulletin 51  ARLP051
From Tad Cook, KT7H
Seattle, WA  December 6, 1996
To all radio amateurs

ARLP051 Propagation de KT7H

Solar activity surely declined this week compared to last.  The
past couple of days have had a sunspot number of zero, the average
sunspot number declined over 38 points, and the average solar flux
dropped over 11 points when compared to the previous week.

As solar region 7999 crosses over the Sun's west limb, solar flux
is declining to the values of a few weeks ago, and is expected to
remain around 70 or lower until after the middle of the month.
Unless something new materializes and creeps around the Sun's east
limb to surprise us, after December 16 the flux should rise to a
high around 94 and then drop back below 90 around December 29.

Geomagnetic activity is projected to stay fairly quiet, with some
moderately unstable conditions projected around December 17, with
an A index around 12.  The Boulder A index is currently very low at
1, and the K index as this is written is zero.  The A index is
expected to bump around between 8 and 10 for most of the period
from December 8 to 24.

KL1V of Valdez, Alaska wrote to say that on November 23 from
1926 to 2109 UTC and again on the 25th from 1954 to 2321 UTC 15 meters
was open to the Pacific, South American and the southern U.S. and
was unlike any conditions he had experienced since about 2 years
ago.  Signals were booming in on 15 at well over S9.  He hopes that
it is a sign of good things to come.  I hope so too, but in fact
the recent surprising activity was probably a last blast from the
previous solar cycle, since it came from low latitudes, which don't
usually show much activity until later in a new cycle.

Sunspot Numbers for November 28 through December 4 were 37, 34, 33,
34, 11, 0 and 0, with a mean of 21.3.  10.7 cm flux was 98.1, 91,
87.5, 83.1, 78, 72.8 and 70.7, with a mean of 83.  Planetary A
indices for the same period were 5, 4, 2, 2, 8, 5, and 7, with a
mean of 4.7.


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