ARRL

ARRL Propagation Bulletin ARLP024 (1996)

SB PROP @ ARL $ARLP024
ARLP024 Propagation de KT7H

ZCZC AP45
QST de W1AW
Propagation Forecast Bulletin 24  ARLP024
From Tad Cook, KT7H
Seattle, WA  June 15, 1996
To all radio amateurs

SB PROP ARL ARLP024
ARLP024 Propagation de KT7H

May had several periods of spotless days, where no sunspots were
visible.  Late April and early May had ten days with no spots, save
for one day with a sunspot number of 13.  Following this was a four
day period of no spots, then an eight day period after a two day
respite.  Now we may be headed into another spotless period.

As we reach the bottom of this solar cycle it is interesting to
look at the rise in the number of spotless days per month.  An
early period of no spots was April, 1995 which had over ten
spotless days.  After this the spotless days per month declined,
and then had a fairly steady rise since August of last year.  Since
January of this year every month has had over ten spotless days,
and May had over 15.  There is a good chance that the next ten days
or so could be mostly spotless, since the predicted solar flux is
headed toward the mid-sixties, and is not expected to go over
seventy until the end of the month.

During this period of inactivity the geomagnetic field is quiet,
meaning that there is less absorption over high latitude paths.

During May some new sunspots appeared which seem to be from the
upcoming solar cycle.  Region 7963 appeared in the North on May 10,
followed by a couple of unnumbered regions in the south on May 17
and 19.  Region 7965 showed up on May 22, and 7967 on May 31.

Sunspot Numbers for June 6 through 13 were 32, 38, 29, 34, 17, 11
and 11, with a mean of 24.6.  10.7 cm flux was 72, 73, 70, 70, 69,
68, and 67.4, with a mean of 69.9.
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