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The K7RA Solar Update


The average daily sunspot numbers rose this week from 56 to 81.3, while the average daily solar flux increased from 101.4 to 129.7. Sunspot numbers for September 20-26 were 68, 74, 46, 57, 90, 121 and 113, with a mean of 81.3. The 10.7 cm flux was 117.4, 116.9, 124.5, 133.6, 136.6, 139.8 and 139.2, with a mean of 129.7. The estimated planetary A indices were 9, 5, 4, 2, 2, 2 and 6, with a mean of 4.3. The estimated mid-latitude A indices were 10, 5, 3, 1, 2, 2 and 6, with a mean of 4.1.

As reported in The ARRL Letter on Thursday, September 27, the increase in solar flux was expected to continue over the next few days, with the solar flux peaking at 150 on September 28-29 -- but what a difference a single day makes. You can see the radical change in forecasts by going here and selecting the September 26 prediction, and then compare it to the September 27 prediction. Instead of a solar flux on September 28-October 1 of 150, 150, 145 and 145, the latest prediction for those days is 130, 130, 125 and 125. Each day shows a 20 point lower solar flux than the earlier prediction.

So as it is now, from the September 27 prediction, we see solar flux of 130 on September 28-29, 125 on September 30-October 2, 120 on October 3-4, 130 on October 5, 125 on October 6-7, 120 on October 8, 115 on October 9-10, 120 on October 11, 115 on October 12-13, and rising to 120 on October 14-15. It is then expected to rise to a peak of 150 on October 20 and 150 again on October 25-26, with the average solar flux on October 21-24 around 141.

The average planetary A index declined from 7.4 last week (September 13-19) to 4.3 this week (September 20-26). The predicted planetary A index values are 5 on every day through October 4, then up to 8 on October 5, 5 on October 6-11, then 10 and 12 on October 12-13, and 5 on October 14-16, followed by 10 on October 17, 8 on October 18-20, and down again to 5 on October 21-25.

John Parnell, K7HV, of Seattle, Washington, has enjoyed working DX with low power and then documenting each new country worked on video, for what he refers to as “YouTube DXCC.” Check out his videos. John also reports from K7SS some great conditions on 10 meters last weekend (September 22-23).

We also heard of great 12 meter conditions last weekend from Chris Callicott, G4DJJ, of Northumberland, England: “Between 1810-1850 on September 22, I worked 15 stations across Illinois, Indiana, Minnesota, Ohio and Wisconsin. On September 23 from 1600-1620, the band opened from the UK to the Central and Southwest US, giving easy SSB QSOs with 35 stations in Arizona, California, Nevada, Washington, Illinois, Indiana, Minnesota, Michigan, Ohio, Wisconsin and Mexico. All loaded up to LoTW, of course!”

A little solar activity helps, and of course we have transitioned to fall conditions, which makes a big difference. The equinox was last weekend on September 22 at 1449 UTC.

Angel Santana-Diaz, WP3GW, of Trujillo Alto, Puerto Rico, reports: “I suppose you had a big report on 10 meters this weekend! The afternoon of Saturday, September 22 was really busy on 10. Around 1534, I worked V5/DL3ZAD and at 1556, VP9LP. Later, at 1951 and 2001, I worked 7Z1TT, EA9BW and EA7QC, who told me it was around 10 PM his local time. The band was teeming with life! Then on Monday, I worked JX9JKA on 12 meters at 1915 UTC, which is a new DXCC entity for me. On other bands, I worked ZB2B, T77NM, 8P6CF and OX3KQ. And the bands still are interesting -- I hope they are great for the CQ WW SSB Contest next month.”

Both John Kelley, K4WY, of Fairfax Station, Virginia, and John Campbell, K4NFE of Huntsville, Alabama, sent a tip about an article that claims we actually reached a sunspot cycle peak last year, but that was just for the Sun’s northern hemisphere; the peak for the southern hemisphere may not occur until 2014. Although the article talks about the disconnect between the two hemispheres, suggesting a grand minima in our future, note the comment from Michael Proctor, a solar physicist at the University of Cambridge, who is not convinced that this will happen: “This present cycle is similar to the weak one that ended in 1913, and that was followed by a strong cycle.”

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.




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