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The K7RA Solar Update


Solar activity increased over the past couple of weeks, with average daily sunspot numbers at 13.4 on October 19-25, compared to 1.7 over the previous seven days. Average daily solar flux increased from 70.5 to 76.7 over the same two weeks.

The reason for the radically different averages is because this past week there were just two days with no sunspots, and the previous week had no sunspot activity on six of the seven days. Thanks to Don Wright, AA2F, for noticing that the averages shown at the bottom of last week’s bulletin ARLP042 were carried over from the previous week’s bulletin, ARLP041.

Average daily planetary A index was 11.6, declining from 21.1 to 11.6, and average daily mid-latitude A index decreased from 16.7 to 9.1.

Predicted solar flux for the near term is 78 on October 27, 77 on October 28-30, 76 on October 31 through November 2, 77 on November 3, then 84 and 82 on November 4-5, 80 on November 6-17, 82 on November 18-19, 84 on November 20, 85 on November 21-30, then 84 and 82 on December 1-2, and 80 on December 3-10.

Predicted planetary A index is 16, 12 and 8 on October 27-29, 5 on October 30-31, then 8 and 16 on November 1-2, 15 on November 3, 5 on November 4-6,  then 28, 30, 40, 28, 26 and 8 on November 7-12, 5 on November 13-14, then 12, 10, 8, 6 and 5 on November 15-19, then 18, 45, 40, 18 and 12 on November 20-24, then 10, 8, 5, 8 and 10 on November 25-29, then 5 on November 30 through December 3, then 28, 30, 40, 28, 26 and 8 on December 4-9, and 5 on November 10.

David Moore sent this:

F. K. Janda, OK1HH of the Czech Propagation Interested Group presents his Geomagnetic activity forecast for the period October 27 to November 22, 2017.

Geomagnetic field will be:
Quiet on November 4, 6, 12-13
Mostly quiet on October 29-31, November 1, 3, 5, 15-17, 19
Quiet to unsettled on October 28, November 2, 18, 20
Quiet to active on October 27, November 7, 11, 14, 22
Active to disturbed on November 8-10, (21)

Amplifications of the solar wind from coronal holes are expected
on October (31), November (1-3,) 9-14, 20-21

- Parenthesis means lower probability of activity enhancement.
- Current forecasts remain less reliable.

Jeff, N8II, of West Virginia on October 26 wrote: “It has been a very interesting week on the bands with two major European-to-East Coast 10-meter band openings and other days with 10-meter QSOs with Europe from here in West Virginia near DC.

“On Friday, October 20, my first contact on 15-meter SSB was LY3W in Lithuania, a much farther north opening than usual. I then checked 12-meter CW and found 3B8DB in Mauritius at 1318Z. After a brief break at 1338Z, a run of western and southern Europeans answered my 12-meter SSB CQs working as far east as Bulgaria.

“I then noticed a cluster spot of DM500RT in Germany on 10-meter CW, who I had just worked on 12-meter CW and SSB, and he was good copy 559 and logged him at 1355Z.

“Italian and French stations were logged over the next 15 minutes, followed by Brian, 9J2BO, in Zambia -- all CW. At 1458Z, Henry, IZ5CML was found S9 on 10-meter SSB and that was followed by a nice run of Europeans on SSB.

“I logged Croatia and three Malta calls, all from the same station (9H9GSM) getting ready for the Boy Scout jamboree. I also picked up Portugal, Spain, Balearic Island (EA6/DK5IR), and many Italians including two 5th area mobiles (IW5EKR/M was S9).

“My last European contact was with Spain at 1536Z. At 1518Z S01WS, Western Sahara was logged on 10-meter CW. 3C0L on Annobon Island, operated by two very talented Lithuanians, was logged at 1804Z on 10-meter CW. I then had a run of very loud Brazilians on 10-meter SSB right after 3C0L. The SFI was around 73, extremely low for an F2 10-meter opening to Europe.

“The second noteworthy day was Tuesday, October 24. At 1501Z, YL2BJ in Latvia was found on 12-meter CW, the first northern European contact of the season. Then, after a break, I heard an OH8 station on 10-meter CW calling in a pile up on Trinidad.

“Moments later, I found OF6LW in Finland CQing with a S9 signal and worked him at 1620Z. I then was called by Finns OH3XR and OG2T, as OH0Z on Aland Island, and LA5LJA in Norway.

“Peter, SM2CEW, called on 10-meter CW and said he could see bright aurora and the K index indeed rose to 4 here, followed by as high as 6 later in the day.

“All the Scandinavians had polar or auroral flutter, but only LA5LJA had noticeably degraded copy with a buzzing note. I experienced a similar opening in early March 2015 during the ARRL International DX contest, but the SFI was high enough that nearly all of Europe was workable. The opening was most likely auroral sporadic E linked to F2 on my end.

“Later, at 1642Z, GI4DOH was found on 10-meter CW. I went on to log Spain, Ceuta (EA9ABC), Madeira Island, Gibraltar, and finally Canary Island at 1852Z. SSB activity was high around 1800Z with good backscatter for USA signals, but the European opening did not favor my area. None of the southern European stations had any flutter.”

For more information concerning radio propagation, see the ARRL Technical Information Service at  For an explanation of numbers used in this bulletin, see

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Sunspot numbers for October 19 through 25, 2017 were 0, 0, 11, 13, 23, 23, and 24, with a mean of 13.4. 10.7 cm flux was 73.4, 75.7, 76.5, 77.3, 78, 77.5, and 78.8, with a mean of 76.7. Estimated planetary A indices were 12, 8, 10, 6, 6, 18, and 21, with a mean of 11.6. Estimated mid-latitude A indices were 9, 5, 13, 6, 3, 13, and 15, with a mean of 9.1.