QST de W1AW
Propagation Forecast Bulletin 52 ARLP052
From Tad Cook, K7VVV
Seattle, WA December 7, 2001
To all radio amateurs
SB PROP ARL ARLP052
ARLP051 Propagation de K7VVV
This has been a quiet week with no geomagnetic disturbances. Each day's planetary A indices have been in the single digits, indicating stable conditions without the high absorption of HF radio signals associated with solar coronal holes and flares.
Average sunspot numbers were up more than 84 points, and average solar flux rose by nearly 49 points. Solar flux has probably peaked for the short term in the past few days.
For this weekend, Friday through Monday, solar flux is predicted at 225, 225, 220 and 210. Planetary A indices are expected at 8, 8, 15 and 15. The rising A index is possible because of sunspot 9727, currently moving toward the center of the visible solar disk with a complex magnetic field harboring the possibility for solar flares.
Average daily solar flux values for November were up slightly from the previous month, and were a fairly high monthly value for the year. Average daily solar flux for January through November was 166.6, 147.2, 177.7, 178.2, 148.7, 173.7, 131.3, 163.1, 233.8, 208.1 and 212.7.
Holographic images of the sun's far side show no substantial sunspots. Barring any emerging activity, the next short term minimum in solar flux is expected from December 16-20.
This weekend is the ARRL 160 Meter Contest. The following weekend is the ARRL 10 Meter Contest. Conditions should be good for the 160-meter event, barring any geomagnetic upset. The 10 Meter Contest seems to be around a lull in predicted sunspot/solar flux activity, but we should have an update next week.
Recently, 6-meter operators have been working a great deal of DX via F2 layer propagation. K7MCX in Seattle wrote that on December 4 at 2342 UTC he worked JA7BZU on 6 meters. When he checked his log, he found that his last QSO with this station was exactly 12 years earlier at 2350 UTC on December 4, 1989. This was at the peak of the previous sunspot cycle. Then, 23 minutes later at 0005 UTC on December 5 he worked JO1MWX, a station he'd also worked on 6 meters on December 5, 1989.
Sunspot numbers for November 29 through December 5 were 204, 158, 208, 271, 230, 214 and 260, with a mean of 220.7. The 10.7-cm flux was 216.4, 225.8, 221.3, 245, 235, 233.3 and 237, with a mean of 230.5. Estimated planetary A indices were 3, 3, 7, 4, 7, 6 and 8, with a mean of 5.4.