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ARRL Propagation Bulletin ARLP021 (1996)

ARLP021 Propagation de KT7H

Propagation Forecast Bulletin 21  ARLP021
From Tad Cook, KT7H
Seattle, WA  May 24, 1996
To all radio amateurs

ARLP021 Propagation de KT7H

There were four consecutive days of zero sunspots last week.  The
average solar flux was down five points from the previous period.
Expect similar conditions through the rest of 1996 as we experience
the solar minimum.

A note from Shel Shallon, W6EL pointed out that the progress of any
solar cycle is judged in terms of smoothed sunspot numbers, and that
the smoothed number for a given month is an average of 13 months of
data, centered on the month of interest.   Therefore we won't really
know when the sunspot cycle minimum has occurred until some time
after the event.  Shel is the author of the popular Mini Prop
propagation prediction software.

Shel goes on to say: ''Reports last year that the first spots from
cycle 23 had been observed were erroneous.  It is now believed that
the first spot from cycle 23 was observed on May 10, 1996.
Typically, the sunspot cycle minimum does not occur until at least
twelve months following the appearance of the first spots of new
cycle.  Therefore, the minimum between cycles 22 and 23, and the
official start of cycle 23, may not occur before May 1997.''

Current solar flux progress for the short term points to a slow rise
to a peak just above 70 around June 7 or 8, and then a drop below 70
around the middle of June.

For the WPX contest this weekend look for more of the same
conditions; few sunspots with a quiet geomagnetic field.

Sunspot Numbers for May 16 through 22 were 26, 12, 0, 0, 0, 0 and
11, with a mean of 7.  10.7 cm flux was 71, 71.2, 70.3, 68.8, 68,
66.9 and 66, with a mean of 68.9.


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