ARLP036 Propagation de K7VVV:
August 31, 2001

Propagation Forecast Bulletin 36 ARLP036
From Tad Cook, K7VVV
Seattle, WA August 31, 2001
To all radio amateurs

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

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.

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.