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The K7RA Solar Update


Weakening sunspot activity continues. Average daily sunspot numbers dropped from 59 in the previous seven days to 54.1 during the week of February 26 through March 4.

Average daily solar flux actually rose a little, with values increasing from 116.3 to 122.9 over the same two weeks. In addition, on March 5 the noon reading for solar flux in Penticton was 140.2, but this was an outlier, reduced by NOAA to an official value of 130 for the day.

The average daily sunspot number from December 1 through February 28 was 98.2. This value centered on January 2015 adds to our archive of 3-month moving averages. According to our moving average, the cycle peaked in February and March 2014, with average daily sunspot numbers of 146.4 and 148.2. The February value was calculated by adding together all the daily sunspot numbers from January 1, 2014 through March 31, 2014, then dividing by the number of days. The March value added all daily sunspot numbers from February 1 thought April 30. This smoothing makes it easier to spot peaks and trends. Since then the trend has been down in the past year.

Following February and March, the three month averages centered on April through December 2014 were 129.6, 118.4, 112.8, 109.2, 115.6, 108.4, 107, 104.7 and 107.8. From there it dropped to 98.2 for the recent period.

Don’t forget: the vernal equinox is only two weeks away and around this time the Northern and Southern Hemispheres are bathed in equal measures of solar radiation. We should enjoy enhanced HF radio propagation. Also, this weekend is the SSB portion of the ARRL International DX Contest. See for details. The outlook is good for the weekend.

Predicted solar flux from NOAA and USAF is 135 on March 6-7, 130 on March 8-10, 135 on March 11-12, 130 on March 13-15, 135 on March 16-17, then 130 and 125 on March 18-19 and 120 on March 20-21. Flux values then hit a minimum for the short term on March 24-25 at 110, then rise to 135 on April 12-13, according to the forecast.

The predicted flux values for March 6-12 are significantly higher than in the March 4 forecast, used in Thursday’s edition of the ARRL Letter. Those reported values averaged to 121.4, while a day later the average values for the same period is 132.9. This indicates a temporary upward trend in the prediction.

Predicted planetary A index is 8 on March 6-8, then 12, 15, and 12 on March 9-11, then 8, 5, 8 and 5 on March 12-15, then 15 on March 16-17, 8 on March 18, 5 on March 19-21, then 15, 20 and 8 on March 22-24, 5 on March 25-26, then 15, 30, 25, 15 and 10 on March 27-31, and 8 on April 1-4. The predicted planetary A index at 30 on March 26 is quite high, and is perhaps an echo of March 1-2 when the A index was 28. Over those same two days, the high latitude college A index at Fairbanks, Alaska was 36 and 60.

According to on March 1-2 a solar wind brought aurora borealis to the Arctic Circle, and at 1530 UTC on March 2 an M3 class solar flare erupted, but not aimed toward earth. A blast of extreme ultra-violet radiation from the flare ionized the upper layer of Earth’s atmosphere, causing a radio blackout below 10 MHz. This was most strongly evident over South America, as shown in this blackout map at .

Petr Kolman, OK1MGW, predicts mostly quiet geomagnetic conditions on March 6-7, quiet to unsettled March 8-10, quiet March 11-13, mostly quiet March 14, quiet to unsettled March 15, quiet to active March 16-18, mostly quiet March 19-20, quiet to unsettled March 21, quiet to active March 22, active to disturbed March 23, quiet to unsettled March 24, mostly quiet March 25-26, quiet to unsettled March 27, active to disturbed March 28-29, and quiet to unsettled again on March 30-31.

Robert Elek, W3HKK of Johnstown, Ohio wrote: “Had fun chasing 3G0ZC around the bands with my KW to assorted wire antennas from here in central Ohio. Ten, 12, 15, 17, 80, 40, 30 and 20 meter contacts were put in the log (5 bands on one afternoon alone!), but 160 eluded me.

“Heard them twice (both nights of the 160 meter SSB contest) but QRM was brutal at my end from the SSB boys. I slept through the next night’s 160m window (I heard they peaked nicely between 5:45 and 6 AM EST then disappeared), but stood guard the final two nights between 5:30 and 6 AM, but heard nothing from them, or anyone else calling them, for that matter. Read they had bad generator noise (and maybe QRN?) that limited them to just 76 QSOs on Top Band. Bummer.

“Fast forward to 4-5 March. After working through the 3G0ZC pile ups for Robinson Caruso Island, I was happy to just casually listen around the bands while puttering in the (spare bedroom) shack, and between trips to watch TV with my wife. Bands seemed unusually quiet - free from QRN and QRM. Frankly, not a lot coming through.

“Soon after, I enjoyed an amazing sequence of QSOs. At 2357Z on 4 March I worked JY4NE on 20 CW with his nice signal. Then a few minutes later added JT1CO on 17 meter CW at 0010Z on 5 March, and E51UFF at 0020Z on 10 CW. Then JW9JKA on 20 CW at 0032Z. Wow! I made contact with stations in the Middle East, Mongolia, the South Cook Islands, and Arctic Europe all in a span of 35 minutes - without the benefit of a beam antenna!

“I took a break for a couple of hours, watching TV and happy with a very nice world-wide string of FB DX.

“Then, from 0500-0612Z, another string began. I worked TR8CA on 40 CW at 0500Z, then I dropped down to 160 and heard very little. But all of a sudden TI5/KL9A went into the log at a very solid 579 at 0513Z. As I poked around the quiet band there was KH6AT also 579 (at his sunset, no less!) calling CQ at 0539Z. At 0550Z I heard DK2CF at 569 calling CQ.

“I decided it was time to move back to 40 meters and see what was happening there. At 0610Z V73NS in the Marshall Islands was calling CQ just above the noise. It was still daylight there, maybe 2 hours before their sunset, and he was coming through fine. And finally, at 0612Z, here comes E51UFF from the South Cook islands again.

“I had just enjoyed a feast of worldwide DX during about 90 minutes of casual operating, covering 10, 17, 20, 40 and 160 meters. I scanned 40 SSB and heard about a dozen European and Russian DX stations, including a female operator from Moldova who was attracting a crowd. Nothing else new, however, so I pulled the switch and went to bed.

“This was one of those unexpected and very warm, fuzzy periods of operating that you don't forget, because the propagation gods were smiling.”

Excellent! Thanks for the report. In a subsequent e-mail, W3HKK continued: “Tad, I’ve been reading up on ON4UN’s Low Band DXing book and noticed his comments about "spotlight" propagation, especially on 160 meters. That perfectly describes several recent contacts on that band with a KH6, a near contact with a CX6 tonight, and with a couple of Europeans.

“Nobody was coming through on the band. Then, all of a sudden, a DX signal appears, but no one was responding to his CQs. I jump in and work him in short order. He then goes back to CQing with only the occasional taker. A couple of Hungarian stations appear on the band, but get few takers. During this time there were isolated strong signals for a period of time from South America, Europe, and the Pacific.

“Sixty meters has been exploding with DX lately. With the 100 W limit and more countries getting onboard, 60 meters has been a gold mine of DX. Tonight alone I worked 4Z4, GW0, ZD8, and LB6. Imagine that! LZ, OH, K1N, HI8, CY0 and V47 were other 60 meter contacts that went in the log during February.

“This new 8-direction SAL-30 receiving antenna is letting me see where signals are coming from, as well as providing a nice 20 dB or so F/B on LF, AM broadcast, and the 160 through 40 meter bands. It’s a joy to have on the low bands.”

You can read more about his all-wire antennas and his new receiving antenna by logging into, then go to

The Robinson Crusoe Island operation (which ended on March 4) has a neat propagation tool on their web site at .

Several readers, including AB1DD, have mentioned recently, with videos by Dr. Tamitha Skov explaining solar phenomena. Check out , and . She also has a channel at .

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 e-mail distribution of ARRL bulletins are at

Sunspot numbers for February 26 through March 4 were 39, 58, 70, 66, 65, 38, and 43, with a mean of 54.1. 10.7 cm flux was 111.3, 118, 123.4, 127.6, 130.4, 125.1, and 124.2, with a mean of 122.9. Estimated planetary A indices were 5, 4, 13, 28, 28, 11, and 10, with a mean of 14.1. Estimated mid-latitude A indices were 5, 2, 11, 23, 18, 10, and 9, with a mean of 11.1.




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