ARLP044 Propagation de K7VVV:
October 31, 1997

Propagation Forecast Bulletin 44 ARLP044
From Tad Cook, K7VVV
Seattle, WA October 31, 1997
To all radio amateurs

SB PROP ARL ARLP044 ARLP044 Propagation de K7VVV

Disturbed conditions forecast for last weekend hit quite hard. A coronal mass ejection a few days earlier caused the planetary A index to hit 25 last Friday, 19 on Saturday and 14 on Sunday. This caused HF havoc during the CQ Worldwide DX Contest.

Last week we saw the average solar flux drop a few points, and the average sunspot number decline by 10. At the same time the average flux for the previous 90 days went up by one point from 86 to 87, and the solar flux was below this average for six out of the seven days.

This weekend is the ARRL CW Sweepstakes, and conditions for this domestic contest should be quite a bit better. Conditions are expected to be quiet to unsettled, with solar flux climbing from 90 to 95.

Northwest Research Associates has an interesting web site devoted to space weather, including charts of 10.7 cm solar flux, effective sunspot numbers and geomagnetic indices. Check it out at

Sunspot Numbers for October 23 through 29 were 0, 11, 13, 14, 44, 50 and 41 with a mean of 24.7. 10.7 cm flux was 79.7, 78.6, 81.4, 82, 84.4, 85.5 and 87.2, with a mean of 82.7, and estimated planetary A indices were 6, 25, 19, 14, 15, 13, and 10, with a mean of 14.6.

Here are some projections for domestic paths for this contest weekend: