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ARRL Propagation Bulletin ARLP040 (2002)

ARLP040 Propagation de K7VVV

QST de W1AW  
Propagation Forecast Bulletin 40  ARLP040
From Tad Cook, K7VVV
Seattle, WA  September 27, 2002
To all radio amateurs 

ARLP040 Propagation de K7VVV

Over the seven days of September 19-25 conditions were quiet with no
real geomagnetic activity except some unsettled conditions on the
19th. The sun has also been quiet. Average sunspot numbers were down
slightly for the past week and average solar flux was down quite a
lot. Solar flux over the past two weeks has declined from over 200
toward 150, and over the next few days it is expected to go below

After October 3 sunspots and solar flux are expected to rise, based
upon the previous solar rotation. Flux values are expected to reach
200 again in the second week of October. Currently holographic
images show no substantial sunspots on the sun's far side.

We are now in the Fall season, a great time for HF DX. Openings are
better and longer, particularly on the higher frequencies. Although
solar activity is still fairly high, we have passed the peak of the
sunspot cycle, and this Fall will probably be far better for HF
propagation than next Fall.

12 and 10-meters are now open to parts of the world that were
unheard a couple of months back. For most of North America 12 and 10
should be open in the middle of the day toward Europe, during all
daylight hours toward South America, and to Asia and the Pacific
late in the afternoon to early evening. 12-meters will generally
open earlier and close later than 10-meters.

For the CQ/RJ Worldwide RTTY DX Contest this weekend expect good
conditions with no radio blackouts or solar flares likely.

Sunspot numbers for September 19 through 25 were 206, 237, 217, 218,
209, 240 and 230, with a mean of 222.4. 10.7 cm flux was 165.3,
164.4, 158.6, 160, 153.8, 157.9, and 153.4, with a mean of 159.1.
Estimated planetary A indices were 13, 6, 9, 9, 5, 6, and 6, with a
mean of 7.7.


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