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The K7RA Solar Update


This is a catch-up bulletin released Monday morning after the Thanksgiving holiday.

We had quite an active week on November 14-20, and today we are reporting the numbers for the following week, November 21-27, and beyond.

Average daily sunspot numbers fell from 193.3 in the earlier period to 63.6 in the latter, and in the four days since then, November 28 through December 1, the average daily sunspot number rose to 100.3.

Average daily solar flux was also off, from 166.9 in the earlier period to 130 in the latter, then in the following four days the average solar flux was 130.8.

Geomagnetic indices were quiet, except that on November 29 through December 1 the planetary A index was 8, 9 and 10. Still, these are very moderate numbers, indicating conditions were slightly unsettled.

Predicted solar flux is 130 on December 2, 135 on December 3-4, then 140, 145, 140, 135 and 140 on December 5-9, 165 on December 9-14, then 160, 155 and 145 on December 15-17, 140 on December 18-19, 135 on December 20, and 130 on December 21-24.

Predicted planetary A index is 15 on December 2, 10 on December 3, 5 on December 4-5, 8 on December 6, 12 on December 7-8, 8 on December 9, 5 on December 10-12, then 10 and 8 on December 13-14, 5 on December 15-21, then 8, 10 and 8 on December 22-24, and 5 on December 25-30.

Now that November is over, let’s look at sunspot number averages. Our 3-month moving average is up following increased activity, and we now know the 3-month average centered on October (including all data from September 1 through November 30.) The three month moving average of daily sunspot numbers centered on January through October is 73.6, 80.7, 85.2, 106.4, 106.4, 97.5, 85.6, 77.4, 91.2 and 102.9.

The monthly averages of daily sunspot numbers for June through November 2013 were 80.2, 86.2, 90.2, 55, 127.2 and 125.7.

For those interested in whether recent activity is part of a second double peak in this cycle, the earlier peak at the end of 2011 had monthly averages for September through December of 106.4, 123.6, 133.1 and 106.4.

On November 27, Dean Lewis, W9WGV, of Palatine, Illinois sent this report about the fun he had on ten meters during the CQ Worldwide CW DX Contest, with a very simple indoor antenna: “Last weekend’s 10 meter propagation was amazing; I worked three JAs; two on 10 meters, one on 15 meters; this may not sound like any great shakes to most, but being ‘CC&R-challenged’, I run 10 watts from an Icom 703 to a carefully pruned indoor end-fed 40 meter half-wave wire (full wave on 20 meters, three half-waves on 15 meters, two full waves on 10 meters with no feed line or RF ground, and a very simple small matching device). The signals were all well over S9 and no QSB; no fills, no repeats, no errors. Also worked a number of European stations, Niger, the Caribbean, and South America, plus KH6 and KL7. Ten was like the low end of 40 meters on a winter night. Don’t remember when last I had to use the 500-cycle CW filter on 10 meter, but I did on Saturday and Sunday.”

Dan Bates, N5TM, of Katy, Texas also enjoyed ten meters during the CQ Worldwide CW weekend: “I’ve never seen 10 meters with stations all the way up to 28.160 as was the case on Sunday morning of the CQWW.  Propagation opened to the Far East late in the contest and my last two Qs were to China and East Malaysia on 15 meters.” Dan also has restricted antenna space and operates very low profile.

For more information concerning radio propagation, see the ARRL Technical Information Service at For an explanation of the numbers used in this bulletin, see An archive of past propagation bulletins is at More good information and tutorials on propagation are at

Monthly propagation charts between four USA regions and twelve overseas locations are at

Instructions for starting or ending email distribution of ARRL bulletins are at

Sunspot numbers for November 21 through 27 were 85, 51, 65, 69, 52, 47, and 76, with a mean of 63.6. 10.7 cm flux was 141.2, 142.8, 135.6, 127.1, 119.1, 115.5, and 129, with a mean of 130. Estimated planetary A indices were 3, 3, 8, 2, 2, 2, and 2, with a mean of 3.1. Estimated mid-latitude A indices were 1, 2, 6, 2, 2, 2, and 2, with a mean of 2.4.



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