The K7RA Solar Update


2008 was a year of very low solar activity. More than 40 percent of this year's propagation bulletins reported zero sunspots for their respective weeks. The average daily sunspot number for the year was 4.7; in 2007, it was 12.8. The yearly averages of daily sunspot numbers for 1999-2008 were 136.3, 173, 170.3, 176.6, 109.2, 68.6, 48.9, 26.1, 12.8 and 4.7. Sunspot numbers for December 25-31 were 0, 0, 0, 0, 0, 0 and 0 with a mean of 0. The 10.7 cm flux was 69.3, 69.2, 69.4, 69.8, 69.8, 68.5 and 69.3 with a mean of 69.3. The estimated planetary A indices were 3, 1, 1, 2, 0, 1 and 10 with a mean of 2.6. The estimated mid-latitude A indices were 2, 2, 1, 1, 1, 1 and 8 with a mean of 2.3.

Two years ago we wrote, "This is the first bulletin of 2007, the year we'll likely see the end of sunspot Cycle 23, the beginning of Cycle 24, and the minima between cycles." One year ago in the first bulletin of 2008 we noted the same quote from the previous year, and wrote, "Now a year later we might say the same about 2008." This is probably still true for past year, because since early 2008, we saw Solar Cycle 24 spots, and what looks like a slow increase in activity toward the end of the year, although a week of sunspots at the end of December would have helped to sustain the upturn.

We've been looking at a three month moving average of sunspot numbers, and the average for October-December -- centered on November -- was 4.4, about the same as the number 4.5 centered on October. Here are the 3-month sunspot number averages since early 2007:

Jan 07 22.7
Feb 07 18.5
Mar 07 11.2
Apr 07 12.2
May 07 15.8
Jun 07 18.7
Jul 07 15.4
Aug 07 10.2
Sep 07 5.4
Oct 07 3.0
Nov 07 6.9
Dec 07 8.1
Jan 08 8.5
Feb 08 8.4
Mar 08 8.4
Apr 08 8.9
May 08 5.0
Jun 08 3.7
Jul 08 2.0
Aug 08 1.1
Sep 08 2.5
Oct 08 4.5
Nov 08 4.4

For those readers who track the solar cycle using Scott Craig's Solar Data Plotting Utility, there is a new data file on his Web site containing 20 years of data, from January 1, 1989 through December 31, 2008. The program can automatically suck up the data from the text of our bulletins. You can download the software for Windows and the update from the WA4TTK Web site. The updated data file is available directly here.

Mike Hoteling, KD7IBE, of Colville, Washington, wrote, "Just want to report some good propagation from Northeastern Washington on 160 meters late at night. These quiet sunspot conditions offer some unique opportunities. QSO into Wyoming and Texas complete with QSL cards with the century club on 1892 kHz with 100 W into a 75 meter dipole at 35 feet. Don't be afraid to give it a try!"

Elwood Downey, WB0OEW, of Socorro, New Mexico, along with many other readers, called attention to recent news from NASA that the ionosphere is now at lower elevation than in the past. I suppose this means that worldwide shortwave signals might not propagate as far. Read the article that Elwood sent here.

A number of readers, including Norm Priebe, W7ISD, of Alexandria, Minnesota, sent in links to articles about a big hole in our Earth's magnetic fields. The magnetosphere helps protect us from solar wind, so if these findings are correct, it wouldn't take strong space weather to trigger aurora.

Dave Deatrick, WA8OLD, was mentioned in ARLP051 back in December, 2006, when he told about the fun he was having on 40 meters with a shortened dipole in a vee configuration at 30 feet. He wrote again on December 20, 2008 to report more fun from the far north of Michigan with the same antenna, and about 4.8 dB more power (300 W vs 100 W). He lives about a mile from the Canadian border at Sault Ste Marie, and writes "Forty meters CW has been good lately, especially from about 1000 to 1200 UTC to the Caribbean and South America. I just worked H6VA at 1155 this morning, December 20. I was also able to work an AH6 same time period during the CQWW CW contest".

The local newspaper in Homer, Alaska ran an article this week about aurora borealis; this geophysical event often can be seen from Homer..

Finally, nothing to do with propagation, but check out this link to a historical page dedicated to the Novice license.

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 in The ARRL Letter. Check 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.