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The K7RA Solar Update


All four of the indices we track rose over the past week, with average daily sunspot number rising from 50.6 to 86.6, average daily solar flux up from 105.4 to 117.4, average daily planetary A index increasing from 7.3 to 9.4, and average daily mid-latitude A index up from 5.6 to 6.4.

Predicted solar flux for the near term is 110 and 105 on February 12-13, 105 on February 14-16, 111, 100, 105 and 110 on February 17-20, 115 on February 21-23, then 110 and 112 on February 24-25, 115 on February 26-27, 112 on February 28-29, then 110, 105, 100, 105 and 100 on March 1-5, 115 on March 6-7, then 118, 115 and 112 on March 8-10, 110 on March 11-14, and 112 on March 15-16.

Predicted planetary A index is 12, 10, 6 and 5 on February 12-15, then 8, 20, 12, 10 and 8 on February 16-20, 5 on February 21-29, then 15, 10, 12, 8 and 5 on March 1-5, 18 on March 6-7, 8 on March 8, 10 on March 9-10, and 5 on March 11-14.

OK1HH predicts geomagnetic activity will be quiet to unsettled on February 12, quiet to active February 13, mostly quiet February 14-15, quiet on February 16, active to disturbed February 17, quiet to active February 18, quiet to unsettled February 19-20, quiet February 21-22, mostly quiet February 23-24, quiet February 25-26, quiet to unsettled February 27, quiet February 28-29, quiet to active March 1, quiet to unsettled March 2, quiet to active March 3, quiet March 4-5, active to disturbed March 6, quiet to active March 7, and quiet to unsettled March 8.

OK1HH expects an increase in solar wind on February 15, 17-21, and 29 through March 3, but he is uncertain about February 15 and 29. According to Spaceweather, s
unspot AR2497 erupted on February 11, producing a C9-class solar flare and hurling a coronal mass ejection (CME) in space, some of which may strike Earth.

Jon Jones, N0JK, of Kansas wrote: “The recent South Georgia VP8SGI DXpedition battled high winds, storms and disturbed geomagnetic conditions. It was challenging for many to try to work them on 10 meters from North America. The statistics bear this out -- VP8SGI reported only 2,080 North American contacts on 10 meters compared with over 5,400 on the 15 meter band. The low solar flux of 120 was a factor. Many days VP8SGI was only a faint ‘whisper’ in North America on 10 and only the largest stations were successful. Propagation did vary day to day. On February 5 the VP8SGI 12 meter signal was the strongest I had heard at 1845z -- an honest 599. I set up fixed mobile from a hilltop with a full 1/4 wave whip on 28 MHz. At 1910z VP8SGI popped up out of the noise on 28.023 MHz and I was able to complete a 10 meter CW contact. Several other NA stations reported working them using dipoles and small Yagis on 10 that day. VP8SGI was hearing very well. Listening and persistence sometimes pay off.”

N8II of Shepherdstown, West Virginia (FM19cj) wrote on February 6: “Thanks for the useful historical data about the cycle. At the peak, 10 meters was fantastic into Asia, Thailand coming thru both morning and evening for about 3 weeks most days and Mongolia was worked in the evening (very difficult path from here). Now we are lucky to hear EU, no signals most days, worse than Oct-Nov 2015 when we had some good openings including especially the phone CQWW. 10 is open to Africa (FR4NT Reunion/ 3B8HC Mauritius worked in past week) and to AZ/CA and farther north most days, but I did not hear any VE7's today on 10 working the BC QSO party. Fifteen meters was open, but seemed poor by 2100Z.

“I also recently worked FR4NT on Reunion on 75-meter SSB around his sunrise. Of interest also were QSO's with K5P on Palmyra long path on both 15 SSB and 12-meter CW around 1900-2000Z. They were not readable short path at that time. Finding 12M open that path was amazing to me! 3D2AG/P on Rotuma also had a good signal one day on 15 CW long path mid-January and was loud on 20 CW long path 1900-2000Z day after day.

“Last year, western Minnesota was workable on 15 especially western and northern areas; today in the Minnesota QSO Party I worked 2 stations very weak on backscatter only. Of interest was that 20 meters was as close to perfect all day as I can ever remember. I was the right distance away. Many Minnesota mobiles were S9+, easy to copy even through QRM! The last couple of year’s signals went weak for 2-4 hours mid-day on 20. Forty meters did not seem that great, no mobiles for about 5 hours and then QRM from a RTTY contest. Eighty meters was open well enough that W0ZQ/rover was S7-9 on 80 and worked 2-3 other Minnesota mobiles all in the last 20 minutes with contest ending at 2400Z (near sunset in Minnesota).

“One recent afternoon, two Florida stations called me on 20-meter CW running QRP to simple verticals around 2100Z, both were S9 on peaks with solid copy with one running 1 W! I decreased power to 5 W here and they copied me solid. One was portable on the beach. My antenna was a 2 el Yagi at 60 feet, did not even bother to try larger Yagi.”

And N8II wrote again on February 11: “Looking at the SFI numbers, there was no particular reason, SFI from 117 down to 112 today 2/11 (K index 2 thru AM), but the MUF was significantly higher today on the bands. At 1411Z, I found Jonas, LY5A, in Lithuania S9 on 12 meter CW, first LY or around that area heard since probably November on 24 MHz, after a quick hello, it was up to 10 meter CW for QSOs with RM7C in southern Russia who was about S4 on peaks.

“Then I found CN8CE in Morocco and was called by OM3TDD, UW2ZO (Ukraine), followed by a string of south central Europeans ending with biggest surprise, EW3W, in Belarus at 1443Z who was S7. Other signals ranged from S5 to S9. Back on at 1600Z, I found DJ6ZM who was S9 + 30 dB running 500 W to stacked 5/5 Yagis. My 10 meter antenna is a 5 element Yagi on short boom at 99 feet. After logging special Dutch call PG16ANT on CW, I moved up to SSB and was treated to a string of loud mostly British Isle stations with a few Dutch and Germans.

“Many of the Welsh and British stations were S9+ some with very simple verticals or dipoles. The opening did not seem to extend up to Scotland or Norway. The string of QSOs ended with OE2SCM near Salzburg, Austria S9 and CT1EUB in Portugal at 1738Z. I then found 5V7TH in Togo loud and easy to work and very loud (S9+ 20-30db) TK5MH in Corsica on 10 meter SSB. I then switched to 15-meter SSB and was called by England (one 5 W to wire), Germany, Netherlands, and Scotland.

“In the afternoon I found 7P8C in Lesotho on 17 meter SSB and V51WW in Namibia on 12 meter SSB.

“During the CQ 160 Meter CW contest on January 30-31, I found high absorption early with Illinois stations weak even after their sunset and not much of anything workable past the central US. But conditions did improve, and I had a nice run of West Coast (mainly AZ/CA) stations and a good number of Europeans calling from 0420-0615Z Saturday. KH6AT called at 0515Z near his sunset, so I ended up working all states except AK and 42 DXCC countries with similar conditions on Saturday evening/Sunday AM except that many reported good European conditions around 2300Z that I seemed to have largely missed.

“I worked several AZ and CA stations I’ve never worked before on 160 and was called by CW5W in Uruguay with a signal as loud as or louder than the loudest European, and I also worked HC2AO in Ecuador. Conditions toward Europe seemed to favor the north a bit. Two R4 area Russians near the Asia border called in along with Leningrad area, Finland, UA2F Kaliningrad, Sweden, Denmark, and Belarus. I worked a total of 14 German calls and quite a few Czechs and Slovaks, as well as being called by P33W on Cyprus and LX7I in Luxembourg. The hardest to work USA area was definitely the Pacific Northwest with only three WA stations logged and no VE7 (unusual).

On Sunday, February 7, there was a taste of good 10 meter conditions. At 1611Z I ran a string of Dutch, Italian, Spanish, Belgian, Swiss, and French stations. In the midst of the pile up, Francisco, TT8FC, called from Goundi, Chad with a nice S9 signal once I moved antenna to Africa. On the 8th, 12 meters was open to Europe from 1348Z until I finally called it quits at 1505Z with a weak RK3Y in Russia in the log. I also worked two Italians, one Swiss and E73RO with good signals on 10 meters from 1410-1430Z.”

Last week I mentioned that I hoped to review a new edition of the ACE-HF propagation prediction program. I received the package on Monday, but I haven’t received the installation key yet.

In the solar flux prediction archive, February 8 saw a significant jump across the board in expected solar flux, at about 10-15 percent. You can download the archive 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

My own archives of the NOAA/USAF daily 45 day forecast for solar flux and planetary A index are in downloadable spreadsheet format at and

Click on “Download this file” to download the archive, and ignore the security warning about file format. Pop-up blockers may suppress the download.

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 February 4 through 10 were 95, 113, 71, 84, 82, 79, and 82, with a mean of 86.6. 10.7 cm flux was 123.3, 119.7, 117.1, 117.1, 115.2, 117.3, and 112.2, with a mean of 117.4. Estimated planetary A indices were 6, 12, 8, 8, 17, 10, and 5, with a mean of 9.4. Estimated mid-latitude A indices were 5, 8, 5, 6, 11, 8, and 4, with a mean of 7.4.




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