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ARRL Propagation Bulletin ARLP014 (1996)

ARLP014 Propagation de KT7H

Propagation Forecast Bulletin 14  ARLP014
From Tad Cook, KT7H
Seattle, WA  April 6, 1996
To all radio amateurs

ARLP014 Propagation de KT7H

Solar activity remains very low.  Two days last week, March 30 and
31, had a zero sunspot count, and as this bulletin is being written
a week later the Sun is again spotless.

Over the next few weeks expect the solar flux to remain near 70,
with possible mild geomagnetic disturbances centered around April 7
and April 17.

20 meters is the best daytime band, with the solar activity being
too low to sustain much propagation on 15 meters or higher
frequencies.  40 meters is the best band for worldwide
communication at night, with low solar activity making this the
best time of the solar cycle for 160 meters.

Regarding the end of this solar cycle and progress toward the next
one, the latest projections based upon current conditions and
previous solar cycles suggest that for the next few months we will
be at the sunspot number minimum.   The minimum is centered around
April through June of this year, with sunspot numbers reaching the
Fall 1995 levels in February 1997.

Previous bulletins have mentioned a 10.7 cm solar flux minimum
centered around Spring of 1997, but the latest projection moves
that period up a bit toward the current period.  What it shows is a
minimum based on an average flux of 72 for October 1996 through
February 1997, with the flux also averaging 72 for June 1996.  The
projected flux for the dates in between is 73.

Spring of 1998 should present a radically different picture.  By
then the average flux will be climbing toward 100, and 10, 12 and
15 meters should be alive with activity again.  In April 1999 the
average solar flux is projected at 158, and 192 is the value for
April 1999.  The next cycle is projected to peak around the turn of
the century in August, 2000.

Sunspot Numbers for March 28 through April 3 were 24, 22, 0, 0, 13,
14 and 14, with a mean of 12.4.  10.7 cm flux was 71.9, 70.5, 70.2,
70.1, 68.2, 70.7 and 71.1, with a mean of 70.4.


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