QST de W1AW
Propagation Forecast Bulletin 1 ARLP001
From Tad Cook, KT7H
Seattle, WA January 3, 1997
To all radio amateurs
SB PROP ARL ARLP001
ARLP001 Propagation de KT7H
Solar activity was down over the past couple of weeks, as we settle back into conditions consistent with the bottom of the solar cycle after the recent, probably final upsurge in activity from the dying cycle 22.
Looking at the long term, recent data shows that sunspot numbers probably bottomed out around June or July of last year, but should return to late 1994 levels around June of this year. By August some projections show sunspot numbers about three times what they were during the same month a year earlier, and by December about four times the average for December, 1996.
For the ARRL RTTY Roundup this weekend look for slightly rising solar flux to the mid-seventies, with a possible small bump in geomagnetic activity coming Monday. Based on the 27 day solar rotation, the flux is expected to rise to around the mid-eighties by January 14, then drop below 80 a few days later, bottoming out in the low seventies from January 17 through the end of the month.
Recently 15 meters has seen some improvement, although a lot of the observed propagation is north-south, also referred to as transequatorial. Look for openings on 17 through 10 meters during daylight hours, and good conditions on 20 meters. Look for conditions to be best on 20 after sunrise and again before sunset. 40 meters is still a good bet for long and medium distance propagation, and given the continued low solar activity, look for openings on 80 and 160 meters during the long hours of darkness.
Recently we have been unable to get solar flux numbers resolved to a tenth of a point. This should change soon.
Sunspot Numbers for December 19 through 25 were 23, 13, 28, 26, 24, 0 and 0, with a mean of 16.3. 10.7 cm flux was 87.4, 83, 83.7, 81.5, 79.5, 79 and 77, with a mean of 81.6. Planetary A indices for the same period were 2, 2, 4, 6, 10, 3, and 6, with a mean of 4.7.
Sunspot Numbers for December 26 through January 1 were 0 every day, which is a mean of 0. 10.7 cm flux was 76, 75, 74, 74, 73, 72 and 72, with a mean of 73.7. Planetary A indices for the same period were 3, 1, 4, 3, 8, 4, and 2, with a mean of 3.6.