ARRL

ARRL Propagation Bulletin ARLP012 (2000)

SB PROP @ ARL $ARLP012
ARLP012 Propagation de K7VVV

ZCZC AP12
QST de W1AW  
Propagation Forecast Bulletin 12  ARLP012
From Tad Cook, K7VVV
Seattle, WA  March 24, 2000
To all radio amateurs 

SB PROP ARL ARLP012
ARLP012 Propagation de K7VVV

Spring is here, and 10 and 12 meters are the place to be. A high
solar flux and shifting seasons are again producing conditions where
low power mobiles can work the world on the highest HF bands.

Last year at this time, the average solar flux for the week was
147.5. This week it was 207.8, much higher, and almost 13 points
higher than last week's average. A steady upward recent trend can be
seen in the graph at http://www.dxlc.com/solar/.

Geomagnetic indices have been quite low, but this should change.
Active conditions are predicted for the next few days due to
recurring coronal holes and some recent flare activity. A large
coronal hole that has been returning for several months has split
into three groups, and one of them crosses the sun's equator and is
well positioned for disturbing radio conditions here on earth.

Weekend conditions for the CQ Worldwide WPX Phone Contest could be
stormy. The predicted planetary A index for the next five days,
Friday through Tuesday, is 25, 30, 20, 10 and 10, so it looks like
the best contest conditions may be on Sunday. On March 31 and April
1 conditions may be unsettled or active again, but should be quiet
until April 18. Solar flux predicted for the next five days is 230,
240, 245, 245 and 235. Flux values are expected to bottom out around
185 on April 12 or 13, then peak near 250 around April 22 or 23.

The High-Energy Solar Spectrograph Imager mission was set back at
least six months when the satellite was mistakenly vibrated too hard
in a test on a shake table at the Jet Propulsion Lab. The deployment
of the satellite, which is designed to observe solar flares in their
most energetic wavelengths, was expected to coincide with the solar
maximum this year. You can read about the accident at
http://www.msnbc.com/news/386019.asp?0a=23232C5 and about the HESSI
mission itself at the NASA web site
http://hesperia.gsfc.nasa.gov/hessi/index.html and at a University
of California site, http://hessi.ssl.berkeley.edu/.

Sunspot numbers for March 16 through 22 were 138, 152, 142, 208,
240, 191 and 212 with a mean of 183.3. 10.7 cm flux was 184.4,
192.4, 194.8, 208.2, 210.3, 230.5 and 233.8, with a mean of 207.8,
and estimated planetary A indices were 4, 6, 7, 8, 8, 6 and 11, with
a mean of 7.1.

The path projections for this contest weekend are from Charlotte,
North Carolina.

To Western Europe, 80 meters 2330-0700z, 40 meters 2230-0800z, 20
meters 2030-0530z, 15 meters 1200-2300z, 10 meters 1530-2100z.

To Southern Africa, 80 meters 2300-0430z, 40 meters 2300-0500z, 20
meters 2130-0600z, 15 meters 2100-0230z, 10 meters 2000-0000z.

To South America, 80 meters 2330-1000z, 40 meters 2300-1030z, 20
meters 2200-1100z, 15 meters 1030-1330z and 2000-0700z, 10 meters
1200-0300z.

To the Caribbean, 80 meters 2300-1100z, 40 meters 2000-1330z, 20
meters open all hours, best 2330-0900z, weakest 1500-1900z, 15
meters 1200-0230z, 10 meters 1400-2300z.

To Australia, 80 meters 0900-1200z, 40 meters 0830-1230z, 20 meters
0800-1300z, 15 meters 1300-1500z, 10 meters possibly 1400-1500z or
0200-0300z.

To Japan, 80 meters 0900-1100z, 40 meters 0830-1200z, 20 meters
0800-1300z, 15 meters 2000-0130z, 10 meters 2130-0030z.
NNNN
/EX