QST de W1AW
Propagation Forecast Bulletin 54 ARLP054
>From Tad Cook, K7RA
Seattle, WA December 29, 2003
To all radio amateurs
SB PROP ARL ARLP054 ARLP054 Propagation de K7RA
This is the last Propagation Forecast bulletin for 2003. At the end are the numbers which were not included in last weeks bulletin since it was sent early because of the holiday.
During the reporting week of December 18-24, average solar flux and sunspot numbers were quite a bit higher than the previous seven-day period. Geomagnetic indices showed more stable conditions, with the average planetary A index about half the previous average. Geomagnetic indices have remained stable since December 24th, and sunspot numbers have been dropping along with solar flux.
Geomagnetic conditions should remain stable until Wednesday, December 31, when recurring solar activity is expected to manifest as a rise in A indices. The predicted planetary A index for December 29 to January 11 is 10, 10, 15, 30, 20, 15, 15, 30, 35, 35, 35, 35, 20 and 15. Solar flux is expected to decline over the next few days, dipping below 100 after January 1 and for the following 10 days or so.
Henry Platt, W3UI, wrote to comment on the statement in last week's bulletin concerning quiet geomagnetic conditions on December 24-25. With K indices at 1 or 2, from his home in Bryn Mawr, Pennsylvania using 100 watts and a half sized dipole on 80 meters he was able to work on the first attempt nearly every European call heard. He contrasted this to rough conditions over the past year on the same band with the same gear. The key seemed to be long winter nights with quiet geomagnetic conditions.
This week Straight Key Night is a popular operating activity beginning early New Year's Eve, North American time. It runs the entire 24 hours from 0000-2400z on January 1, and is a fun and relaxed event. The author of this bulletin plans to participate if he can only find his old J-38. For information and rules, see http://www.arrl.org/contests/rules/2004/skn.html.
For more information about propagation and an explanation of the numbers used in this bulletin see the Propagation page on the ARRL Web site at http://www.arrl.org/tis/info/propagation.html.
Sunspot numbers for December 18 through 24 were 114, 113, 104, 105, 152, 144 and 100 with a mean of 118.9. 10.7 cm flux was 123, 122.5, 130.1, 133.4, 137.6, 142 and 138.9, with a mean of 132.5. Estimated planetary A indices were 8, 7, 16, 21, 15, 9 and 8, with a mean of 12.