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The K7RA Solar Update


There were no sunspots for a full week, December 18-24. Christmas Day saw a return to sunspot activity, so the last two of those spotless days were in the Thursday through Wednesday reporting period in this bulletin, December 23-29. The average daily sunspot number for this past week rose nearly 15 points to 19.7, and the average daily solar flux was about the same as last week, moving from 80.1 to 80.3. Sunspot numbers for December 23-29 were 0, 0, 28, 28, 14, 31 and 37, with a mean of 19.7. The 10.7 cm flux was 80.1, 78.6, 79.4, 80.5, 80.1, 80.7 and 82.6, with a mean of 80.3. The estimated planetary A indices were 0, 3, 5, 2, 2, 13 and 3, with a mean of 4. The estimated mid-latitude A indices were 1, 3, 4, 2, 1, 8 and 3, with a mean of 3.1.

The latest forecast from NOAA/USAF shows solar flux for December 31-January 10 at 83, 84, 84, 82, 80, 80, 80, 83, 88, 88 and 88. The predicted planetary A index is 5 on December 31 through January 2, 7 on January 3-6 and 5 again on January 7-10. Our report from Geophysical Institute Prague predicts quiet conditions December 31 to January 3, unsettled geomagnetic conditions January 4, quiet to unsettled January 5 and quiet again on January 6.

Although there are two more days of sunspot and solar flux readings to complete the 2010 data, with 363 data points, we can easily calculate the year’s averages. Yearly averages of daily sunspot numbers for 2004-2010 were 68.6, 48.9, 26.1, 12.8, 4.7, 5.1 and 25.5. Yearly averages of daily noon 10.7 cm solar flux readings from Penticton for 2004-2010 were 106.6, 91.9, 79.9, 73.1, 69, 70.6 and 80.

These averages represent a nice increase in solar activity, but they still indicate a weak solar cycle. We can compare these averages with yearly averages around the end of the previous solar cycle. Solar Cycle 23 probably ended in late 2008, and Solar Cycle 22 ended in mid-1996, so averages based on calendar year are somewhat skewed, whereas counting 365 day periods or perhaps shorter increments after the end of a cycle would not be. For 1993-1998, yearly averages of daily sunspot numbers were 79, 48.1, 28.7, 13.2, 30.7 and 88.7. Over the same period, the yearly averages of daily solar flux were 109.5, 85.8, 77.1, 72, 81 and 117.9.

But looking over the data at hand as presented, tells us that the activity at the minima between Solar Cycles 23 and 24 was lower than between 22 and 23, and Solar Cycle 24 still seems to be advancing much more slowly. Perhaps at another time we could examine the averages over shorter periods following each minimum.

Jon Jones, N0JK, regularly reports on e-skip openings on 6 meters. This time he wrote: “Finally another winter season E-skip opening. From Wichita (EM17), I worked K4UI (EM76) with very loud signals at 0117 UTC December 27. I also heard a couple of ‘5s’ in EL09 and K5AB/EM10. Most of it was going overhead as was too close in for most of the E-skip.”

You can take a look at this opening by querying here. He listed contacts from 0111-0125 on December 27. Just leave everything at default, but select 50 MHz, Reported from 27 December 2010 at 0110 UTC until 27 December 2010 at 0130 UTC, and select the maximum number of returned QSOs at 100 or 250. Click on “Submit Query” and you will see the listing.

You can also click on the NA Map tab to see a map of the paths reported. And if you want, you can expand the times in your query to see more than what Jon reported. Note that if you don’t see QSOs listed all the way to the early and late times you’ve entered, either you have hit the 250 QSO limit or there were no QSOs reported during that period. If you hit the limit, then just narrow the time period and move the period forward and backward in time to get a full report on 6 meter openings. Also note that you can restrict the report to paths greater than some arbitrary value.

Jon also reported working Canada on 6 meter CW on December 28, VE3EN at 0214 UTC and VE2XK at 0309 UTC. You can do a similar search to examine this opening, too.

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 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.




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