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ARRL Propagation Bulletin ARLP003 (1997)

ARLP003 Propagation de KT7H

Propagation Forecast Bulletin 3  ARLP003
From Tad Cook, KT7H
Seattle, WA  January 17, 1997
To all radio amateurs

ARLP003 Propagation de KT7H

Average solar flux and sunspot numbers for the past week were
almost unchanged from the week previous, but there was some
noticeable geomagnetic activity.  A coronal mass ejection from the
Sun on January 6 caused a disturbance four to five days later when
a magnetic plasma cloud caused a severe storm at high latitudes.
The planetary K index rose as high as 6 on January 10 at 0600 and
0900 UTC.  The planetary A index for the day was 31.

Over the next few weeks the solar flux should stay around the low
to mid-seventies, probably 72 to 74 most of the time.  Some
slightly unsettled conditions may appear around January 26, and
again from February 3 to 8, with some possible unstable conditions
on February 6 and 7.  Expect 160 and 80 meters to yield some good
conditions with solar flux low and the nights long.

A wire service story this week said that scientists from NASA and
the astronomy department at Yale University presented findings at a
meeting of the American Astronomical Society in Toronto which
predicted a decrease in overall solar activity for the next solar
cycle.  They admitted that their forecast is at odds with many
other predictions, and that solar activity is highly unpredictable,
but said that if their prediction is correct, it will reverse what
they claim is an overall 400 year trend toward greater solar

Sunspot Numbers for January 9 through 15 were 12, 13, 12, 0, 0, 0
and 14 with a mean of 7.3.  10.7 cm flux was 73.7, 75.4, 74, 74.5,
74.6, 74.9 and 75.8, with a mean of 74.7.  Estimated planetary A
indices for the same period were 6, 31, 13, 10, 5, 4, and 4, with a
mean of 10.4.


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