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ARRL Propagation Bulletin ARLP034 (1998)

ARLP034 Propagation de K7VVV

Propagation Forecast Bulletin 34  ARLP034
From Tad Cook, K7VVV
Seattle, WA  August 21, 1998
To all radio amateurs

ARLP034 Propagation de K7VVV

Solar activity was down slightly this past week, but conditions are
still very good and activity is still up.  The average solar flux
for the previous ninety days rose from 112 to 114 this week, and
flux values were about twenty points higher on every day, indicating
a strong upward trend.  The solar cycle is definitely out of the
doldrums.  For dramatic graphic evidence of the strong upward trend,
check out on the web.

Activity should remain strong, with flux rising over the next few
days to 142, 146 and 150 predicted for Friday through Sunday.  The
planetary A index for the same period is predicted at 20, 18 and 10.
Currently the A and K indices are rising as this is being written on
Thursday evening, probably due to a major solar flare on August 18
as well as a northern polar coronal hole that extends somewhat down
the solar surface.  Additional flare activity could come from solar
region 8307 before it departs around the end of August.

Solar flux should continue rising to around 160 for August 25-30,
down to 150 around September 1-7, then up again around September 8
and 9 to 155.  Watch for unsettled conditions around September 5-7.

Look for good 10, 12 and 15 meter conditions as we move toward the
fall equinox in about a month.  With higher solar flux, 10 meters is
opening up, particularly for those who live more toward the equator.
Using a popular propagation prediction program, when I run a path
projection for 10 meters to Ohio from my home in Seattle, the solar
flux must be higher for good signals than if the path is from Los
Angeles to Ohio.  Los Angeles is nearly 1000 miles and 14 degrees
latitude south of Seattle.

There were some interesting VHF propagation reports this week, with
N0HJZ in Minnesota experiencing E-layer openings on both 6 and 2
meters to New Jersey and Connecticut, and 2 meter meteor propagation
from Ontario.  N5JHV in New Mexico worked several Europeans on 6
meters, and N9LR in Illinois worked WA2FGK in Pennsylvania on 222
and 1296 MHz via a tropospheric opening.

Sunspot Numbers for August 13 through 19 were 109, 80, 106, 90, 90,
104 and 132 with a mean of 101.6.  10.7 cm flux was 136.8, 137,
133.4, 139.7, 136.3, 132.6 and 134.6, with a mean of 135.8, and
estimated planetary A indices were 9, 7, 6, 5, 5, 6, and 9, with a
mean of 6.7.


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