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The K7RA Solar Update


Solar activity seems to dip back into the doldrums again, with the average sunspot number for the past week (72) lower than any reporting week since bulletin ARLP013, which was for the week of March 21-27. You can go through the recent bulletins at and note that two weeks ago we had twice that number, when the average daily sunspot number was 144. From last week, the average dropped more than 12 points from 94.3. Average daily solar flux was down more than 10 points to 107.6.

But tracking the 3-month moving average of daily sunspot numbers, (which is based on calendar months) the three months ending May 31 had a much higher average than the 3 months ending April 30, and in fact more than any trailing three month average since the one ending on January 2012.

At the end of 2011 we saw a rally in solar activity, and with the weak activity in all of 2012 some are suggesting another double-peaked solar cycle. The three month periods centered on July through December 2011 had average sunspot numbers of 63, 79.6, 98.6, 118.8, 118.6 and 110. The first few months of 2012 were weaker, with the 3-month averages centered on January through March at 83.3, 73.7 and 71.2. But now the numbers are trending up. The 3-month averages centered on January through April 2013 were 73.6, 80.7, 85.2 and 106.4.

If you are unfamiliar with moving averages, using our method for the 3-month period centered on March, 2013, we added up all the daily sunspot numbers from February 1 through April 30. The sum was 7,581. We divided by the 89 days in those three months, and got approximately 85.2. For the period centered on April, we added all sunspot numbers from March 1 through May 31, and the sum was 9,792. As there were 92 days in this period, the average rounds off to 106.4.

On June 3 NASA updated their forecast for the peak of the current solar cycle, available at This differs from a month earlier, when on May 1 they predicted a cycle maximum in fall 2013 with a smoothed international sunspot number of 66. Now they predict a peak at 67 in summer 2013. Summer officially begins at the solstice, two weeks from today, on June 21 at 0504 UTC, which by the way is the Friday before Field Day weekend.

The active geomagnetic days over the past week were June 1-2, when the planetary A index was 49 and 19, the mid-latitude index was 41 and 16, and the high latitude college A index (measured near Fairbanks, Alaska) was 58 and 44. These numbers reflect the concentration of geomagnetic activity toward the poles. The source was an interplanetary shock wave of uncertain origin.

Again as this bulletin is written early Friday morning on the West Coast, we are in a geomagnetic storm, the result of the earth passing through south-pointing magnetism in the solar wind. There is a possibility on June 8 of getting buffeted again, this time the result of a CME, and possibly two.

The planetary A index was 17 on June 6, with increasing K-index values from 2 to 3 to 4. Now early on June 7 we see planetary K-index of 5 and 6, which is the equivalent to an A index reading of 64. Now after 1200 UTC it dropped to 56.

The Australian Space Forecast center issued a geomagnetic disturbance warning at 0217 UTC on June 7. It reads, “A CME from a disappearing solar filament has arrived earlier than anticipated and is accompanied by a strongly southward pointing magnetic field. This is producing Minor Storm levels of activity in polar regions and may produce Active conditions at mid latitudes over the next 1-2 days.” They predict a minor geomagnetic storm today, June 7, and unsettled to active conditions through the weekend, June 8-9.

The latest prediction from USAF/NOAA is for solar flux at 110 on June 7, 105 on June 8-9, 100 on June 10, 95 on June 11-12, 100 and 105 on June 13-14, 120 on June 15-16, 125 on June 17-19, then with flux values bottoming out at 105 on June 24-28, and rising to 125 on July 2 and again on July 14-16.

Predicted planetary A index is 18 on June 7-8, then 10 and 8 on June 9-10, 5 on June 11-20, then 25, 18, 10 and 8 on June 21-24, 5 on June 25-27, then 30, 20, 12, 8, 5, 8, 12, 10 and 5 on June 28 through July 6.

Petr Kolman, OK1MGW predicted a quiet geomagnetic field for June 7 (the prediction was sent around 1900 UTC on June 6), mostly quiet June 8-9, quiet June 10, quiet to unsettled June 11, quiet to active June 12-14, mostly quiet June 15-17, quiet June 18, quiet to unsettled June 19-20, active to disturbed June 21, quiet to active June 22-23, quiet to unsettled June 24, mostly quiet June 25-26, quiet to active June 27, and active to disturbed June 28-29. You can see quite a difference from the NOAA/USAF prediction in the previous paragraph, but the NOAA forecasters have the advantage of revising their forecast every 24 hours, while OK1HH and OK1MGW only do it once per week.

Bert Cook, K6CSL of Riverbank, California which is northeast of Modesto in the San Joaquin Valley, wrote to comment about the ARRL Propagation Charts. He finds them useful, but said the monthly charts are never available until well into the new month. I checked and learned these are prepared by the lab at ARRL headquarters, but the delay is due to some technical issues that may not be resolved right away.

As these are prepared using the VOACAP prediction engine, I suggested an alternative that should suit his needs if he would rather not set up the VOACAP program himself. Several months back we mentioned the subscription service at There is a free 30-day trial, and if you should choose to continue, the subscription cost is reasonable. This has the advantage of customization for the user’s exact location, plus you can make predictions for future months as well.

You can also customize your account for antennas and power levels, and when you run the program it emails you a set of URLs for the bands you have chosen as well as the region, either North America or world wide. Rather than look at these online, I found it much better to download the pdf files, then page through the 24 hourly pages for each band. You get a set of beautifully rendered maps with colors corresponding to coverage areas and signal levels. When you can quickly flip through these after downloading, you watch the projection of the signal levels for different areas progress across the map, hour-by-hour.

Another alternative is to use the free W6ELprop software for Windows computers. Check the K9LA tutorial at, and you can download the software at W6ELprop is free, but K6TU tells me he is about to add some great new features to his service.

Larry Nelson, K5IJB of El Paso, Texas reports: “Several 6-meter CW beacon stations were very helpful last Sunday (June 2) when listening for band openings. From about mid-morning up to noon, these beacons were S9 as the band opened to the West and mid-West from El Paso: N0LL/B, N7DGI/B, WB0RMO/B, W5GPM/B, and N0SAP/B. I made several CW and SSB contacts using the Icom 703 (10 watts) to a homebrew vertical dipole at 25 feet.”

Lou DiChiaro, WB2IJT reported “As a Navy civilian physicist, I don't get to spend much time on the air during the work week. However, I do occasionally get on the air over the weekends. This past Saturday (June 1) was an extraordinary day for Es on 6 meters. I'm running 100 watts out from an IC-7000 to a large loop antenna running around the inside perimeter of my attic (to avoid the wrath of the subdivision esthetics enforcers). From Grid Square FM29 (Delaware) I worked in quick succession a number of Florida stations, some in Georgia, Arkansas, and Missouri. One of the Georgia stations measured S9+20 dB on the S meter (he was running a KW into a 5 element Yagi - it helps!).”

“It was a band opening to remember. And I'll bet you're getting lots of reports like mine. Hopefully, we'll get lots more openings like this from Old Sol before he runs out of hydrogen and starts burning helium in his core.”

And finally, Jeff Hartley, N8II reports from West Virginia: “From 0245-0400Z Friday May 31 I caught the best conditions towards EU on 15M I can ever remember so late in the evening, in 42 years on the air.  Since the solar flux was around 120, my guess would be there was a sporadic E link to the opening on the North American end, but the stations worked were in daylight ranging from around sunrise to mid morning. Prefixes worked in order from 0242-0306Z on 15 CW were DJ2, UT7, UA3, UT9, RA1, RA4LW (S9+5db, then +20 db at 0330Z!), UK8OWW, SP7.  Then, I tried some CQ's on 12M with no answer and scanned 10M towards EU where there were no signals to the NE including beacons, but several W6 beacons were loud via double hop Es. I went back to 15 CW at 0328Z and worked RU4, YO4, LA6, RZ6, UB6, UR4, UX7, RD3, UA6, and LZ2 thru 0352Z.

I made a quick check of 15 SSB and found Ed, 4Z4UR who was S9. He mentioned he uses WWV near Fort Collins on 20 MHz often as a propagation indicator for NA, a smart idea. He says he can frequently hear WWV around 0300-0400Z at this time of year indicating a band opening which I would guess rarely extends as far east as my QTH in FM19cj. I checked 15 the next night around the same time and there was no opening to anywhere.

On June 1 from 0125-0149Z, I did catch UN5C and UN5J with good signals on 17M CW as well as FO8WBB, ZL1BD, and a VP2V on 12M. 10M was dead including beacons. During the day I worked the AL QSO party in which even 10M was open to AL on Es from 19Z thru about 0020Z, though it was not utilized by most AL stations. All of the stations I asked to QSY to 10M up from 15 or 20M were successfully logged mostly with very strong signals. 15 was fairly active on CW and 20 was in great shape with strong signals all day until about 0120Z. 40M was barely usable at first, but was open from here pretty well from 2045Z onward. The high bands were the best ever to AL in the ALQP from here. In the late afternoon, I also worked AF3X/M on 20 roaming around the NYC boroughs with S9 signals only about 250 miles away.

I operated part time in the WPX CW contest May 25-26 on 20M. Conditions were disturbed at the beginning, then quite so Saturday 1200Z thru at least 0300Z Sunday. There were some very loud southern and central EU at the start thru around 0115Z when the band gradually closed. A few Russians and Asians were found, but were almost gone by 0215Z whereas normally I have run pile ups from western Asiatic and European Russians from 0200-0400Z on 20 CW. Sunday 0100-0200Z was pretty much rock bottom, but I managed somehow to work all continents except EU during that time. RC9O who would normally peak around 20 degrees peaked around 310 degrees on a very skewed path and was only about S4. SA was loud and I worked KH7 and ZL3. Sunday at 1400Z, 20 seemed back to near normal as it did at 2345Z, but I only had time to operate mainly in the 14Z hour when many northern EU stations not possible to work before due to conditions were logged.”

Thanks, Jeff!

For more information concerning radio propagation, see the ARRL Technical Information Service at For an explanation of the numbers used in this bulletin, see 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 May 30 through June 5 were 71, 58, 60, 76, 99, 59, and 81, with a mean of 72. 10.7 cm flux was 104.1, 101.8, 105.8, 110.9, 111.8, 109.9, and 108.8, with a mean of 107.6. Estimated planetary A indices were 3, 9, 49, 19, 10, 10, and 6, with a mean of 15.1. Estimated mid-latitude A indices were 2, 7, 41, 16, 9, 10, and 9, with a mean of 13.4.

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.





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