The K7RA Solar Update


We don’t know if this is a significant trend, but solar activity has really leveled off recently. But not everyone is unhappy about this. During the recent long minimum, 160 and 80 meter operators sang the praises of great conditions. In response to my “we hope it isn’t true (prediction for a low solar cycle) comment in last week’s Solar Update, Ken Meinken, WA8JXM, of Aberdeen, Ohio wrote: “Why would that be badYou are showing your 20-15-10 meter bias. To those of us who prefer 160, 80 and 40 meters, the lower the sunspots, the better. Personally, I prefer the low part of the sunspot cycle to the peak. Of course I understand that other hams have various different opinions.”

Sunspot numbers for February 16-22 were 41, 53, 63, 69, 72, 61 and 31, with a mean of 55.7. The 10.7 cm flux was 103.2, 103.7, 104.1, 105.3, 111.1, 103.3 and 104.2, with a mean of 105. The estimated planetary A indices were 4, 2, 4, 16, 16, 6 and 8, with a mean of 8. The estimated mid-latitude A indices were 4, 2, 3, 11, 14, 4 and 9, with a mean of 6.7.

The average indicators this week were almost exactly the same as last. The average daily sunspot number rose from 55.6 to 55.7, while the average daily solar flux declined 2.6 points to 105. In an unusual coincidence, the planetary A index and mid-latitude numbers were the same this week as last: 8 and 6.7.

The geomagnetic activity was concentrated around February 19-20, and was the result of a solar wind stream, causing aurora visible in the lower 48 states. Tim Goeppinger, K6GEP of Orange, California, reports an amazing 10 meter aurora opening between the West Coast of the US and Scandinavia last Saturday night, February 18.

The latest prediction shows solar flux at 105 on February 24-25, 100 on February 26-29, 105 on March 1, 100 on March 2-4, 105 on March 5-11, 110 on March 12-13, and up to 115 on March 14-19. The prediction sees the planetary A index at 5 on February 24-March 1, 8 on March 2-3, 5 on March 4-6, 8 on March 7, and 5 on March 8-10.

Jeff Harley, N8II of Shepherdstown, West Virginia, wrote on February 18: “Ten meters has been open to Europe most days here recently, but nothing like the openings this past October-December. In the PACC Dutch contest last weekend, Dutch stations were worked as early as 1330 and as late as about 1645, with the best conditions around 1620-1640. I worked a total of about 27 PA-PI stations on 10 meters and 20 was open past 2030, but most Dutch stations migrated down to 40 and lower quite early.

“This weekend was a salt mine weekend, so time was limited in the ARRL International DX CW Contest. I stayed on 20 meters and worked what I could, working about 132 QSOs in 31 countries in about 2.5 hours, between 0030-0315. Conditions over the pole were very good, my very first CQ was answered by a BA1 station, then Singapore, two Thai stations, Kazakhstan, South Korea, quite a few Japanese stations and many Zone 18 and 19 Siberian Russians all answered CQs. The increased polar daylight is improving and lengthening the 20 meter polar openings. The band was open well to the Caribbean at first and Africa, and even CS2C in Portugal. Also the big gun in Finland and Norway were logged.

“Saturday morning, 20 was wide open to Europe by before sunrise, and also open to Zone 17 and 18 in Russia, with signals from there having a wicked flutter. Two Thai stations called in and signals stayed very strong from Europe until around 1400. Then I checked 10 meters, which was open to areas very unexpected/poorly explainable for a SFI of only 103. UA1AFT running 5 W was about S6, as was another loud RA1 and stations in Finland, Sweden, Denmark, Lithuania, Latvia, Moldova and Ukraine were all logged. Some of the best signals were from Poland, but Germany just to the west was marginal, as were stations in Great Britain and Belgium. I logged a lot of stations in the Czech Republic and Italy, but at times even the Italian stations were somewhat weak. Around 1530, the Balkans big guns in Slovenia, Croatia and E7DX in Bosnia-Herzegovina were S9+. My 10 meter CQ QSO rate was never very high, but there was fairly steady stream of stations. Signals from the Caribbean farther south than the Cayman Islands were generally S9+.”

Thanks, Jeff.

Julio Medina, NP3CW, of San Juan, Puerto Rico, wrote: “Last night (February 22), I was able to contact CP6UA in Bolivia on 50.115 MHz after been looking for him for long time. This is my new one, for 124 entities worked. It was a nice contact from grid square FK68wl to FH82ue. It took me nearly 10 years to complete all South America countries. Today (February 23), I heard many strong stations hear in Puerto Rico on 6 meters: from Argentina, Uruguay and Brazil. Among them were CX1DDO, LU2DPW, PY2LED, CX6DH and PY1RO.”

CP6UA asked if there are any propagation prediction programs that work for 6 meters. I was pretty sure there are none, but I inquired with Carl Luetzelschwab, K9LA, for comments: “None of our propagation prediction programs cover 6 meters -- they stop at 30 MHz. The reason why is the extremely dynamic nature of the F2 region, which varies widely on a day-to-day basis due to other factors than solar radiation. Thus, our understanding of the F2 region is statistical in nature over a month’s time frame, and this ultimately results in extremely low predicted probabilities for 6 meters since the frequency is so high. Coupled with this is the fact that 6 meter propagation may not be simply refraction -- it may involve scatter, help from the underlying E region and some other things.”

Carl has an article on predicting 6 meter F2 propagation, which you can read here.

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, and an abbreviated version appears each Thursday in The ARRL Letter. You can find a guide to articles and programs concerning propagation here. Check here and here for a detailed explanation of the numbers used in this bulletin. An archive of past propagation bulletins can be found here. You can find monthly propagation charts between four USA regions and 12 overseas locations here. Readers may contact the author via e-mail.