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The K7RA Solar Update


Average daily sunspot numbers over the past week rose over 23 points to 109.4, compared to the previous reporting week. Average daily solar flux was up nearly 21 points to 127.9. Two days, July 6 and July 10, had the most geomagnetic activity, with a planetary A index of 25 on July 10. Planetary A index of July 6 was 21.

The forecast issued on July 7 had a predicted solar flux of 145 on July 11-12, and 150 on July 13-15, but alas, this has been scaled back.  The latest forecast calls for solar flux at 110 on July 12-14, then 105, 110, 115 and 120 on July 15-18, 125 on July 19-20, then 120, 110 and 105 on July 21-23, 100 on July 24-25, 105 on July 26, 110 on July 27-28, then 120, 125 and 130 on July 29-31.

Predicted planetary A index is 8, 15, 25, 12, 8 and 10 on July 12-17, then 15 on July 18-21, 8 on July 22, 5 on July 23 to August 3, and 10 on August 4-5.

OK1HH of the Czech Propagation Interest Group has his own geomagnetic forecast, and he foresees a mostly quiet geomagnetic field on July 12, active to disturbed on July 13, quiet to active July 14, quiet July 15, mostly quiet July 16, quiet to unsettled July 17, quiet to active July 18, quiet to unsettled July 19, active to disturbed July 20, quiet to active July 21, quiet to unsettled July 22, quiet July 23-24, quiet to unsettled July 25, quiet to active July 26, quiet to unsettled July 27-28, quiet July 29-31, mostly quiet August 1, quiet to active August 2, active to disturbed August 3, quiet August 4-5, and active to disturbed again on August 6-7.

Carl Luetzelschwab, K9LA is now hosting the installation file for the W6ELprop Propagation Prediction Program, which is free, and runs on computers running the Windows operating system. The file disappeared from the W6EL web page, and now you can find it by going to and clicking on Tutorials on the left side.  The file is W6ELPropInst270.exe.

Ted Leaf, K6HI sent a link to an article about a large sunspot group, . The article says activity in the Sun’s southern hemisphere is finally picking up. It goes on to claim that this could be an indication of a double sunspot peak, with a second peak emerging as late as early 2014. I would love to see our Sun peppered with energetic spots. Unfortunately in this cycle, when they do emerge they tend to be weak, evidence of the overall listless nature of this cycle.

K9LA talks about a second peak in his article from May 2013 at .

Several articles this week of interest to sun watchers:

The ON4AA site, not mentioned here in some time:

From N0NBH:

A real-time 160 meter propagation tool:

Sorry, no reports from readers this week.

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 July 4 through 10 were 109, 113, 115, 112, 143, 98, and 76, with a mean of 109.4. 10.7 cm flux was 137.7, 140.8, 134.2, 125.6, 119.3, 119.9, and 117.9, with a mean of 127.9. Estimated planetary A indices were 5, 9, 21, 8, 6, 9, and 25, with a mean of 11.9. Estimated mid-latitude A indices were 4, 10, 20, 7, 7, 8, and 20, with a mean of 10.9.



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