ARRL Propagation Bulletin ARLP016 (1998)

ARLP016 Propagation de K7VVV

Propagation Forecast Bulletin 16  ARLP016
From Tad Cook, K7VVV
Seattle, WA  April 17, 1998
To all radio amateurs

ARLP016 Propagation de K7VVV

Solar activity has remained fairly high over the past week.  Average
sunspot numbers were up almost 30 points, and average solar flux was
about that same, at 122.  Average solar flux for the previous 90
days went up another two points from 102 to 104, and flux values
were above these levels on every day, indicating a good upward

April 9 saw a new high in sunspot number for the current cycle, when
it reached 192.  The sunspot number has not been that high since
October 26, 1992, when it was 193.

Solar flux for this weekend, April 17-19 is predicted to be 100, 100
and 95.  Through the end of the month look for solar flux to bounce
around between 95 and 108, then rise above 110 after May 2, peaking
around 125 about a week later.  Geomagnetic indices may be unsettled
today and also around April 24 and 25.

Higher solar activity has extended long distance 20 meter openings
well into the evening.  From the author's home in Seattle, New
Zealand and Australia are strong on 20 meters even as late as
midnight.  Look for openings on higher frequencies as well, although
on 10 and 12 meters the openings tend to be over north- south paths.

Next week this bulletin will be written by KH6BZF while the author
is on Maui.  Listen for us at KH6X until April 25.

Sunspot Numbers for April 9 through 15 were 192, 145, 132, 111, 82,
83 and 79 with a mean of 117.7.  10.7 cm flux was 139.7, 129.7,
128.3, 117, 114.8, 111.9 and 112.7, with a mean of 122, and
estimated planetary A indices were 9, 11, 12, 9, 5, 8, and 4, with a
mean of 8.3.

Here are some path projections to Hawaii from the continental United

From the west coast try 80 meters from 0400-1430z, 40 from 0230-
1630z, 30 from 0100-1030z and 1230-1800z, 20 from 1630-0800z, 17
from 1830-0500z, 15 on some days from 1900-0300z and on rare days 10
may be open from 2000-0000z.

From the midwest try 80 from 0430-1300z, 40 from 0330-1400z, 30 from
0230-1500z, 20 from 1400-1445z and 1600-0800z with better conditions
later in the period, 17 from 1600-0630z, 15 from 1730-0400z and 10
on some days from 1900-0300z.

From the east coast try 80 from 0430-1100z, 40 from 0400-1200z, 30
from 0230-0730z and 0930-1300z, 20 around 1400z, 1600-1730z and
2300-0600z.  Check 17 from 1630-0400z and 15 from 1900-2330z.