The K7RA Solar Update
Solar activity quieted this week, with the average daily sunspot numbers down nearly 37 points to 58.4 and the average daily solar flux declining 27 points to 116.9. Sunspot numbers for October 25-31 were 58, 71, 59, 55, 75, 56 and 35, with a mean of 58.4. The 10.7 cm flux was 130, 130.7, 121.7, 117, 108.4, 106.3 and 104.2, with a mean of 116.9. The estimated planetary A indices were 4, 4, 4, 3, 3, 2 and 5, with a mean of 3.6. The estimated mid-latitude A indices were 3, 4, 3, 3, 2, 1, and 5, with a mean of 3.
Predicted solar flux values are 100 for November 2-3, 105 on November 4-5, 110 on November 6-9, 120 on November 10-11, 125 on November 12-13, 130 on November 14 and peaking at 135 on November 15-20, then 130, 125 and 120 on November 21-23, and back down to 115 on November 24-26. It then drops to a minimum of 100 on November 29-December 1, then back to a high of 135 by mid-December. The predicted planetary A index is 10 and 8 on November 2-3, 5 on November 4-5, 7 on November 6-7, then 10, 12 and 15 on November 8-10, 5 on November 11 through December 4, and 10, 20 and 15 again on December 5-7, followed by a quiet 5 again through December 16.
A coronal mass ejection (CME) hit the Earth’s magnetic field at 1530 UTC on October 31. This sparked aurora and contributed to the planetary and mid-latitude A index of 17 on November 1, with the college A index (in Alaska) at a stormy 48. The activity is subsiding, with a declining A index predicted through the weekend. This will be important to domestic HF contesters, as the ARRL November CW Sweepstakes is this weekend. Conditions should be pretty good for the contest.
Last weekend (October 27-28) was the SSB portion of the CQ WW DX Contest; the CW weekend is right after Thanksgiving, November 24-25. Jeff Hartley, N8II, in West Virginia reports: “I operated 10 meters (single band) in the contest, but the band was nearly closed as expected at the start, so I migrated down for a few 20 meter contacts. Twenty was open nearly worldwide for the first two hours, with excellent conditions over the pole from just west of Japan all the way across to northern Europe. There were also a few very Southwestern Europeans who were workable, and the Middle East was loud as usual at that time of day. I worked many Russians, including all the call areas. RT4RO was S9 +25 -30dB. I logged stations in China, Indonesia, Qatar, India and Tajikistan, along with some very loud African stations in The Gambia, Cape Verde and Kenya. VK1CC in New South Wales, Australia called in via long path around 0100; it’s unusual to work that path so late. This was probably the best 20 meters has ever been at the contest start in my many years of contesting.
“The solar flux averaged around 120 over the weekend, with Saturday being slightly better. This allowed excellent conditions to all of Europe and fairly long openings to Russia, including UA9s in Zone 17. But propagation was very limited to Central Asia -- I worked two stations in Kazakhstan with good signals on Sunday -- and the in the Far East beyond Japan; conditions were better to there last year. Good European conditions and activity allowed me to make more than 2150 QSOs, with 1000 in the log by 1715 Saturday! There was activity up to above 28.8 MHz during the peak time to Europe. Even stations with poor antennas and those running QRP were easy to work for hours. Conditions to the South Pacific were rather poor (worse than expected), except from 2300-2330 on the last day. Sunday was pretty much dead that direction, except for Hawaii. Stations on Guam and the Mariana Islands were extremely loud from 2100 until 2300, much louder than the Japanese stations.”
Steve Brunt, K6AAB, of Fresno, California reports: “Conditions this weekend (CQ WW CW) were fabulous! Ten meters was open until 0200 on the West Coast. I could have worked 10 meters single band, but didn’t. Fifteen meters was also great with worldwide openings. Twenty meters was open, but there was odd propagation. I could hear lots of Eastern Europeans, but I couldn’t work them. I completely missed Zone 15 on 20 meters.”
Jon Jones, N0JK, in Kansas reports: “Sunday afternoon there were great conditions in the CQ WW SSB contest to the Far East. Many Japanese stations were 20 over S9 on 10 meters just before sunset on Sunday afternoon. I worked Guam, the Mariana Islands, Japan, China and Hawaii with 100 W and a CB mag-mount whip, with most stations worked on the first or second call.”
All times listed are UTC, unless otherwise noted.
Amateur solar observer Tad Cook, K7RA, of Seattle, Washington, provides this weekly report on solar conditions and propagation. This report also is available via W1AW every Friday, and an abbreviated version appears each Thursday in The ARRL Letter. You can find a guide to articles and programs concerning propagation here. Check here and here for a detailed explanation of the numbers used in this bulletin. An archive of past propagation bulletins can be found here. You can find monthly propagation charts between four USA regions and 12 overseas locations here. Readers may contact the author via e-mail.