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ARRL Propagation Bulletin ARLP035 (1996)

ARLP035 Propagation de KT7H

Propagation Forecast Bulletin 35  ARLP035
From Tad Cook, KT7H
Seattle, WA  August 23, 1996
To all radio amateurs

ARLP035 Propagation de KT7H

Solar activity was down again last week, with average solar flux 2.7
points lower than the previous week, and average sunspot numbers
about ten points lower.  Every day last week had a solar flux that
was lower than the average for the previous 90 days, but we have not
actually seen a spotless day since July 25.

Solar activity is expected to rise over the next few days, but only
to the minor degree that one can expect at the bottom of a solar
cycle.  Watch for flux values to rise to the high seventies around
August 28 and 29, and then gradually drift to 70 by September 4 and
below 70 a week later.  No geomagnetic disturbances are expected,
but a recurring active area could come into view causing minor upset
around August 27 and possibly the 28th.  With the coming Fall
equinox, it looks like August 28th or 29th could be the best days
for HF propagation for the near term.

Looking at the long term, the latest figures from NOAA based upon
previous solar cycles predict an up tick in solar flux after the end
of this year, and an increase in sunspots as early as this Fall.  Of
course this is just based on the average values for the past five
solar cycles, and there isn't any consensus on any trends apparent
in previous cycles to tell us for certain if the next one will be
dramatic or not.  But based on past data, the activity beginning
next year and until the end of this century should be quite exciting
for fans of HF propagation.

Sunspot Numbers for August 15 through 21 were 26, 14, 15, 14, 13, 13
and 12, with a mean of 15.3.  10.7 cm flux was 67.6, 67.6, 67.8,
66.7, 67.7, 68.5, and 69.7, with a mean of 67.9.


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