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ARRL Propagation Bulletin ARLP052 (1997)

ARLP052 Propagation de K7VVV

Propagation Forecast Bulletin 52  ARLP052
From Tad Cook, K7VVV
Seattle, WA  December 27, 1997
To all radio amateurs

ARLP052 Propagation de K7VVV

Sunspot numbers were down a little last week, while average solar
flux was up about five points.  Recently the average solar flux for
the previous ninety days had dropped one point from 94 to 93 after
many months of steadily rising, but last week it rose to 94 again.
Solar flux rose above this value for the last three days of the
week.  Geomagnetic activity has been very stable, indicating good
conditions.  Solar flux is expected to peak over this weekend around
104, then drop to 102 by Monday, then drop below 100 next week,
below 90 by January 6, and above 90 again around the middle of the
month.  No geomagnetic disturbances are forecast, although January 6
and 7 could have slightly more active conditions.

For the last bulletin of 1997 an assessment is due, as well as a
look forward into 1998.

A year ago the average solar flux for the first 24 days of December
was 78.8.  This month the average for the same 24 calender days is
97.6, nearly a 19 point gain.  The current NOAA SESC prediction for
smoothed 10.7 cm flux is predicted to increase about 30 points over
the next six months and over 50 points or more a year from now.
Look for better conditions in 1998 as cycle 23 really gets going.
10 and 12 meters should finally open on a regular basis, with
excellent conditions by next Fall.

Sunspot Numbers for December 18 through 24 were 35, 16, 27, 30, 41,
72 and 67 with a mean of 41.1.  10.7 cm flux was 86.2, 87.7, 89.6,
92, 97, 104.1 and 107.8, with a mean of 94.9, and estimated
planetary A indices were 6, 2, 2, 3, 2, 3, and 3, with a mean of 3.


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