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The K7RA Solar Update


Reporting this week from the Hill Country of West Texas in Kerrville, northwest of San Antonio. Happy to report that the food is delicious, the locals very friendly and hospitable, and gas costs only two bucks a gallon. Speed limit on the highways is 75 MPH, and it seems almost like the 1970s again.

We have fallen back to a period of zero sunspots, so far only lasting three days. This was after a brief uptick in solar activity from July 15-21. But looking at the STEREO site we can see that on the opposite side of the Sun there are still sunspots, which should drift back into view as our Sun rotates relative to Earth in a couple of weeks.

After those three blank days, the sunspot number rose to 13 on July 28.

Average daily sunspot number declined from 58.1 to 19.3 (comparing the July 21-27 period to the previous seven days), and average daily solar flux from 103.6 to 82.5. Average daily planetary A index went from 10.6 to 8.7, while the mid-latitude A index declined from 11.1 to 8.9.

Predicted solar flux from USAF and NOAA space weather observers is 70 on July 29 to August 3, 75 on August 4, 80 and 95 on August 5-6, 105 on August 7-16, then 100, 90, 85 and 80 on August 17-20, then 75 on August 21-22, and 70 on August 23-31. Solar flux the goes to 105 on September 3-11.

Predicted planetary A index is 10 and 8 on July 29-30, 5 on July 31 to August 2, 20 on August 3-4, 15 on August 5, 10 on August 6-7, then 20, 8, 12, 10 and 8 on August 8-12, 5 on August 13-14, then 8, 12 and 5 on August 15-17, 8 on August 18-19, then 5, 8, 15, 12, 8, 20, 12 and 8 on August 20-27 and 5 on August 28-29, 20 on August 30-31, 15 on September 1 and 10 on September 2-3, then 20, 8, 12, 10 and 8 on September 4-8.

At 0537 UTC on July 28, 2016 the Australian Space Forecast Centre issued a geomagnetic disturbance warning:

“Elevated geomagnetic activity possible due to the expected arrival of a high speed solar wind stream from a coronal hole on 28 July.


28 Jul:  Unsettled to Active, possible Minor Storm periods
29 Jul:  Quiet to Unsettled, possible Active periods”

Petr Kolman, OK1MGW, of the Czech Propagation Interest Group sent us this forecast:

“Geomagnetic activity forecast for the period July 29-August 24, 2016

Geomagnetic field will be:
Quiet on August 23-24
Mostly quiet on August 1-2, 12-14, 17-18, 22
Quiet to unsettled on July 31, August 5-7, 10-11, 19
Quiet to active on July 29-30, August 3-4, 8-9, 15-16, 20-21
Active to disturbed on August (3-4)

Increases in solar wind from coronal holes are expected: July 29-30, August 2-4, 7-9, 20-21.

Parenthesis (August 3-4) means lower probability of activity enhancement.

Petr Kolman, OK1MGW
(OK1HH & OK1MGW, weekly forecasts since 1978)” reported: “Earth is entering the outskirts of a broad stream of debris from Comet Swift-Tuttle, source of the annual Perseid meteor shower. Forecasters don't expect the shower to peak until Aug.11-13, but already NASA cameras are detecting Perseid fireballs streaking across the night sky as the shower slowly intensifies.” Meteor trails can enhance propagation.

David Moore reported, “Sun blasts out 2016’s strongest solar flare:

Scott Bidstrup, TI3/W7RI, sent this from Costa Rica:

"Here is an article that some of your readers might find interesting about how scientists are discovering that the details of how the solar wind powers auroras are a bit different than had been thought. New satellite data might lead to improved auroral forecasts:

“Been awhile since I've sent in a report on propagation from here in the single-digit latitudes, so here goes.

“On six meters, there's only been two really good openings into the States of any consequence, one on the 14th of June, another on the 12th of July, and so far, no openings at all into the South Pacific or Europe, which is strange, because they're normally common here. So far, I have yet to hear Rémi in New Caledonia, and I usually hear him several times per week.

“The opening on the 12th into the States was a really spectacular one; I got 76 QSOs in the log, easily the best opening since I've been down here in Costa Rica, mostly working the East Coast, but occasionally into the Midwest, as far west as Denver. Worked my first VEs on 6 from here, and got two of them, a half hour apart.

“Everybody's really been singing the blues around here about the lack of openings otherwise, though. Even the nightly TEP openings into South America that are a usual feature of six meters this time of year here, have simply not been happening at all. I've only heard those familiar watery signals twice so far this year, and even then the signals weren't particularly strong, nor were they to any stations I haven't already worked many times.

“The frequent, almost daily Es openings into Venezuela and French Guiana we enjoyed last year are only a memory so far this year. If low-latitude sporadic E is supposed to be correlated with low solar activity, you couldn't have proved it by me.

“The HF bands are also suffering from the lack of solar activity. The higher bands, 20 through 10 meters, have seen noticeably weaker signals, with propagation entirely absent on 10 meters for days at a time, and only a very few weak signals on 15.

“That's ominous, because even during the last solar minimum, there would be a decent, if brief opening on 15 meters most days, and afternoon TEP on 10 meters into South America was a daily occurrence. But it is not happening at all so far this year. Most of my HF activity has been on 20 meters just because there hasn't been any other choice. Even 17 meters hasn't been an option.

“The low bands, too, are affected down here by all this. My local gringo friends and I usually have an early morning coffee klatch on 75 meters between 5 and 6 AM, and until recently, the signals, as soon as we would get on, were strong and stable as one would normally expect on that band.

“But lately, the band has been shortening up for local paths quite a bit later than it ever has in the past - often not until an hour or so after sunrise. At times, the propagation on 75 has been so long that Stateside QRM has been stronger than our local Central American stations! Jay, HP3AK, reports that this has been great for his morning gray-line 75m DXing, especially into VK/ZL, but it has shortened up our morning coffee klatch by a half hour or more, because we just can't make ourselves heard locally early.

This strange propagation seems to be an issue on 40m as well, which often isn't opening up for regional short skip until as late as 9 or even 10 in the morning. It's really bizarre - never seen anything quite like it, even during the last solar minimum. In the past, 40m here has always been open as soon as the Sun was up.

“I've noticed that these really late openings on the low bands seem to be correlated with really low 304 angstrom UV index numbers. I'm noticing that the current SOHO 304a number is very close to the lowest I've ever seen it (a few weeks ago, it was the lowest), even during the last solar minimum. I'm wondering if that's real or if it's degradation of the sensor on the satellite. Judging from how the bands have been behaving, it must be real."

I’ve been intending to run this for weeks, but it keeps falling off the agenda. Notice how there are progressively fewer sunspots, as the record transitions from April 2014 to April 2016 and the months beyond:

And finally, this item is interesting because, among other reasons, I cannot imagine being shut inside a capsule and hurtled through some vast void!

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 21 through 27 were 49, 36, 34, 16, 0, 0, and 0, with a mean of 19.3. 10.7 cm flux was 100.1, 90.4, 86.2, 82.2, 73.6, 73.5, and 71.6, with a mean of 82.5. Estimated planetary A indices were 5, 8, 8, 14, 18, 5, and 3, with a mean of 8.7. Estimated mid-latitude A indices were 6, 8, 10, 12, 15, 7, and 4 with a mean of 8.9.




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