The K7RA Solar Update
There was a modest rise in the average daily sunspot numbers over the past seven days, rising 27 points to 78.3, while the average daily solar flux was up marginally, only 1.6 points to 105.6. The geomagnetic indices also went up, with the planetary A index rising from 5.6 to 6.4, and the middle latitude A index rising from 5.1 to 6. There was a more substantial rise in both the solar flux and sunspot numbers for the past three days, with the solar flux at 104.7, 112.4 and 113.5, and the sunspot numbers at 92, 117 and 106. But that turned around when the sunspot number dropped from 106 to 75 on Thursday, February 21, and the solar flux declined from 113.5 to 108.5.
Sunspot numbers for February 14-20 were 25, 59, 75, 74, 92, 117 and 106, with a mean of 78.3. The 10.7 centimeter flux was 99.5, 100.1, 103.2, 105.5, 104.7, 112.4 and 113.5, with a mean of 105.6. The estimated planetary A indices were 10, 4, 8, 8, 4, 6 and 5, with a mean of 6.4. The estimated mid-latitude A indices were 11, 3, 6, 7, 4, 5 and 6, with a mean of 6.
The predicted solar flux is 105 on February 22-23, 100 on February 24, 95 on February 25-26, 100, 105 and 110 on February 27-March 1, 100 on March 2-3, 95 on March 4-14, 100 on March 15-16, 115 on March 17, and rising to 120 on March 18-20, which represents a peak for the next 45 days. The predicted planetary A index is 8 on February 22, 10 on February 23, 8 on February 24, 5 on February 25-28, 10 and 8 on March 1-2, 5 on March 3-10, 7 on March 11-12, and back down to 5 on March 13-27. Over the next month, we can look forward to improving HF conditions as we progress toward the spring equinox on Wednesday, March 20 at 1102 UTC.
Using a propagation prediction program such as W6ELprop gives us a rough idea of what the seasonal improvement might be. Running two instances of the program simultaneously -- once for February 21 and the other on March 21, but with the same solar flux (I used 107) -- allows me to flip back and forth between the results. I did one for Seattle to Japan, and the 15 meter opening from 2200-0030 on February 21 shows up as a 2130-0500 opening on March 21. Similarly, a 17 meter opening from 2130-0230 on February 21 stretches to 2030-0500 on March 21.
Several news articles, such as this one and this one mentioned a huge growing sunspot group -- Group 1678 -- that might spit out solar flares. This spot, however, is way over on the western horizon (yes, the right side is referred to as “west” on the Sun) and about to slip away from view. It is not geo-effective, which it would be if it appeared in the center of the visible solar disc.
Jon Jones, N0JK, of Lawrence, Kansas, has long enjoyed working 6 meter E-skip and even DX using very modest and even compromised antennas. Jon reported on February 16: “Julian Salas, XE2JS (in grid DL68), had a nice 6 meter E-skip opening to the Midwest on Saturday evening (February 17 UTC). I worked Julian while I was mobile on Interstate 40, west of Lawrence (in grid EM28) with 58 to 59 signals at 0135 UTC. My 6 meter mobile antenna is a 2 meter 5/8 mag-mount whip, a quarter-wave on 6 meters.” Yes, Jon feeds that 2 meter whip directly on 6 meters, with no change in loading or any modification. That distance between him and XE2JS is a little less than 1000 miles.
On February 19, Jon reported: “The whip I currently use has a 1.1/1 SWR on 6 meters. Some 2 meter mag-mount antennas don’t match well on 6 meters and may need to be trimmed.”
On February 21, Jon wrote, “Even better, I heard ZL1RS on CW at 2300 on February 20 on 50.087 MHz, about a 339 RST. This was on an attic dipole. I am sure I could have worked him with better antenna.”
Jeff Hartley, N8II, of Shepherdstown, West Virginia, wrote on February 17: “I had limited time due to working over the weekend, but I found conditions to be excellent on at least on 80, 15 and 10 meters during the ARRL International DX CW Contest. In just a few hours on 80 meters -- around 0140-0440 on Saturday, February 16 and 0230-0400 on Sunday -- I managed to work 270 QSOs and 67 DXCC countries with a 1/4 wave ground plane. Conditions were overall the best to Europe that I can ever remember in a contest. I was able to run a steady stream of callers at times, the best I have ever done on 80. I didn’t make any QSOs with Central Asia, but the well-equipped big guns did work that area. I was called by C4N in Cyprus with a huge signal, and also a 4Z5 (Israel) and A65BP (United Arab Emirates). Russian stations were generally somewhat weaker than Western Europe, but many had good signals all the way to the UA4 area. Big guns RU1A and RL3A were well over S9! ZS1EL in South Africa also called me, as well as about three or four 5 W European stations. At least 3 Brazilian stations also called in from Southern Brazil. The omni-directional antenna does have a few advantages. Activity from Europe was very good on even the second night when traditionally it is very slow. I also noticed that some far Western US stations were working Europe as well.
“Ten meters was very interesting with marginal conditions to Europe on Saturday, but I logged stations in Finland, Lithuania, Latvia and Sweden. There were a few loud signals from Bulgaria, France and Spain. At the same time, stations in the Caribbean were very loud, as was CR2X in the Azores. In Africa, 6V7S, CR3A, 3V8BB and EA9EU all had very good signals. Around 1530, 15 meters was wide open to Europe with booming signals. The solar flux was right around 100.
“On Sunday, I arrived at the perfect time -- around 1400 -- when 10 meters was just opening to Europe. East of Poland, propagation was almost nil except for a weak R7MM and about three weak Ukrainian stations, but I ran a big pile up with a huge number of German stations logged and strong signals from Sweden and Norway. All of Europe east of Poland had good conditions to West Virginia through 1510 when I had to stop. Conditions were better than would be expected with a solar flux of only 103 and a K index of 2-3; it was simply amazing that Europe was booming in.”
On February 19, Jeff wrote: “Last night -- February 18 (but February 19 based on UTC) -- T46RRC in Cuba was on 80 meters and European signals calling them were down 15-20 dB from the levels over the weekend. They were S9+25-30 dB on 160 meters on Monday at 0230, a really awesome signal! They have been so loud that they have had no trouble putting a lot from ‘Mother Russia’ into the log. The 17 meter op in the mornings can be heard running stations in Russian, but will switch over to English when a loud station here booms over the Europeans.”
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.