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ARRL Propagation Bulletin ARLP014 (2002)

ARLP014 Propagation de K7VVV

QST de W1AW  
Propagation Forecast Bulletin 14  ARLP014
From Tad Cook, K7VVV
Seattle, WA  April 5, 2002
To all radio amateurs 

ARLP014 Propagation de K7VVV

Average daily solar flux rose last week by 27 points, and average
sunspot numbers by over 9 points. We've had active geomagnetic
conditions this week caused by a stream of high speed solar wind,
yielding aurora displays at high latitudes. Saturday through
Wednesday were very active, with a number of three-hour periods when
the planetary K index was 4.

Solar flux for the short term is expected to peak around 215 for
Friday and Saturday, then drift below 200 after Tuesday.
Geomagnetic conditions could become slightly active or unsettled on

Currently there is a large complex of sunspots crossing the visible
solar disk. A helioseismic image also shows a pair of large sunspots
on the sun's far side.

Kenzo Nose, JA3EGE wrote in about some great recent 6-meter openings
he observed in Japan. On March 17 from 2035 to 2300z he worked
stations in the South Pacific, and long path into Europe and the
Caribbean. He said it was the most unusual propagation he has
observed in 30 years. He worked 9H1, EH3, IS0, IT9, EH6, FJ5, FM5,
FG5, PJ2, YV5 and P49.

You can reach Kenzo via email at You can reach
the author of this bulletin at

The beginning of April marked the end of the first quarter of 2002
so it is time to look at some of the numbers.

Average daily sunspot numbers for the last five quarters, from
January 1, 2001 to March 31, 2002 were 147.3, 164.8, 170.4, 198.1
and 178.3. Average daily solar flux for the same five periods was
164.4, 166.7, 175.5, 219.1 and 203.9. Both solar flux and sunspot
numbers were higher this past quarter than the first three quarters
of 2001, but lower than the last quarter of last year, which had a
lot of activity.

Average sunspot numbers for the past five months, November through
March, were 178.6, 217.5, 189, 194.5 and 153.1. Average daily solar
flux for the same five months was 215.8, 236.5, 227.3, 205, and

We can definitely see the peak that occurred around December, and
that January of this year had more activity than November of last
year. But March solar flux and sunspots were definitely down.

Sunspot numbers for March 28 through April 3 were 144, 189, 171,
133, 189, 262 and 162 with a mean of 178.6. 10.7 cm flux was 176.2,
181.3, 188.7, 204.4, 207, 206 and 209.4, with a mean of 196.1, and
estimated planetary A indices were 6, 7, 17, 14, 16, 15 and 13 with
a mean of 12.6.


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