ARRL

ARRL Propagation Bulletin ARLP036 (2001)

SB PROP @ ARL $ARLP036
ARLP036 Propagation de K7VVV

ZCZC AP36
QST de W1AW  
Propagation Forecast Bulletin 36  ARLP036
From Tad Cook, K7VVV
Seattle, WA  August 31, 2001
To all radio amateurs 

SB PROP ARL ARLP036
ARLP036 Propagation de K7VVV

Solar flux has been rising this week. There are several new sunspots
visible, and flux values are up around 200 again. Average solar flux
rose nearly 35 points this week. The latest projection shows solar
flux rising above 200 over the next few days. Friday's flux is
expected at 205, with 210 on Saturday and Sunday, and 205 on Monday
and Tuesday.

Sunspot 9591 caused a big stir last weekend when a coronal mass
ejection caused a sudden HF radio blackout. N5XE reported that
everything went dead at his QTH in Oklahoma around 1632z on
Saturday. This was right around the time of a major solar flare,
which WWV reported as occurring at 1635z on Saturday. This was
reported as the largest solar flare since April, 2001.

On Wednesday a pair of new spots appeared on the sun's northeastern
limb, and they pose a threat for more flares.

This is tough to project accurately, but the planetary A index for
Saturday and Monday is predicted at 15, which suggests unsettled
conditions, and 20 for Sunday, which calls for a geomagnetic storm.

KA0OSC asked about the path projections. These are done using Shel
Shallon's W6ELprop software, which can be downloaded at
http://www.qsl.net/w6elprop/ .

Conditions are a bit dicey for the All-Asia DX Phone Contest this
weekend. There have been plenty of sunspots, and this time of year
HF conditions are becoming more fall-like, but geomagnetic
disturbances could be a problem.

Here are some path projections for the All Asia DX Phone Contest
this weekend. These are all plotted toward Japan.

From Minneapolis, Minnesota, 80 meters 0930-1200z, 40 Meters
0830-1230z, 20 meters 0530-0800z and 1200-1600z, 15 meters
2000-0330z, 10 meters possibly 2000-0400z.

From Atlanta, 80 meters 0930-1100z, 40 meters 0830-1130z, 20 meters
0600-0700 and 1100-1400z, 15 meters 1930-0430 and around 1400z, 10
meters 2100-0030z.

From the center of the continental USA, 80 meters 0930-1230z, 40
meters 0830-1300z, 20 meters 0600-0830 and 1230-1600z, 15 meters
2000-0500z, 10 meters 2100-2330z.

From Seattle, 80 meters 0900-1400z, 40 meters 0830-1500z, 20 meters
0600-0900 and 1430-1800z, 15 meters 2030-0500z, 10 meters possibly
2100-0300z.

From New York City, 80 meters 0930-1000z, 40 meters 0900-1100z, 20
meters 1000-1330z, 15 meters 2000-0200z, 10 meters possibly
2000-0200z.

From California, 80 meters 0930-1400z, 40 meters 0830-1430z, 20
meters 0600-1000 and 1330-1630z, 15 meters 2000-0700z, 10 meters
2130-0200z.

From Dallas, Texas, 80 meters 0900-1230z, 40 meters 0830-1230z, 20
meters 0600-0830 and 1130-1530z, 15 meters 1930-0600 and around
1400z, 10 meters 2100-0200z.

Sunspot numbers for August 23 through 29 were 194, 187, 132, 139,
182, 189 and 136 with a mean of 165.6. 10.7 cm flux was 169.7,
174.9, 199, 189.9, 192, 199.2 and 197, with a mean of 188.8, and
estimated planetary A indices were 12, 4, 10, 12, 12, 15 and 9 with
a mean of 10.6.
NNNN
/EX