The K7RA Solar Update
In November 16 edition of the Solar Update, we reported that the average daily sunspot number on November 8-14 was 104.9. In the next seven day reporting period -- November 15-21 -- the average was 126.9, making for a nice increase; with solar flux, the average over the previous period was 129.5. In the most recent period, the average daily sunspot number increased to 138.9. In the four days since the last reporting period ended (November 22-25), the sunspot numbers were weakening at 93, 85, 87 and 64, and the solar flux was 127.7, 126.7, 118 and 121.6.
Sunspot numbers for November 15-21 were 132, 141, 163, 136, 122, 119 and 75, with a mean of 126.9. The 10.7 cm flux was 141.7, 138.3, 135.5, 141, 133.9, 141.2 and 140.4, with a mean of 138.9. The estimated planetary A indices were 3, 5, 7, 5, 4, 11 and 7, with a mean of 6. The estimated mid-latitude A indices were 3, 5, 7, 4, 3, 10 and 7, with a mean of 5.6.
The latest prediction from NOAA/USAF as of Sunday, November 25 has the solar flux at 120 on November 26, 115 on November 27, 110 on November 28, 105 on November 29-30, 100 on December 1-3, 120 on December 4, 125 on December 5-6, 130 on December 7-11, 135 on December 12-15, and peaking at 140 on December 16-17. It then drops to a minimum of 110 on December 26-28 before rising again.
The planetary A index is predicted at 11 and 15 on November 26-27, 8 on November 28-29, 10 on November 30, 8 on December 1, 5 on December 2-4, 10 on December 5-8, 5 and 8 on December 9-10, 5 on December 11-15, 8 on December 16, and down to 5 on December 17-31.
On November 19, Jon Jones, N0JK, of Lawrence, Kansas, reported sporadic E propagation on 6 and 10 meters: “I heard the W4CHA/b in grid square EL88 on 50.079 MHz via E skip around 1740 UTC. No live ops around. About 10 minutes earlier, I worked the PT0S DXpedition while on fixed mobile on 10 meters SSB. I was running 100 W and a mag mount whip antenna on the car. PT0S peaked up to 10 over S-9. I was on a high ridge with a clear shot to PT0S across the Wakarusa River Valley, which helped.”
PT0S was the DXpedition to St Peter and Paul Rocks, which sits in the mid-Atlantic Ocean at 0.9169 degrees north, 29.335 degrees west. We received another interesting report forwarded by Frank Donovan, W3LPL, of Glenwood, Maryland. The report comes from last Thursday, November 22, and was written by George Wallner, AA7JV, who was on the DXpedition:
“During the short openings to Japan, the demand is very strong and pile-ups have very high densities that make copy difficult. Still, we are happy as we have more than 2500 Japanese contacts in the log.
“There was a very good opening late afternoon on 6 meters. Interestingly, just a few minutes before the opening, 20, 17 and 15 meters went almost completely dead. I was operating 20 meters CW and had a huge pile-up. Within one minute, the pile-up completely disappeared. There was not even one weak signal to be heard. Almost instantly, the 6 meter radio came alive and we had more than 200 QSOs in 90 minutes, mostly with Southern Europe. A very nice surprise! Twenty, 17 and 15 meters recovered within a few minutes and we had big pile-ups going 15 minutes after the beginning of the disturbance.
“We got on 160 meters just after sunset at 2000. We could hear European stations working each other, but nobody could hear us. We switched over to 80 meters, where conditions were worse; 80 sounded like a bad 160. We then moved to 40 meters and worked both CW and SSB for a few hours, returning to 160 meters at 2145, by which time 160 was in decent shape and we were able to work a steady stream of European stations until about 1230 when conditions deteriorated. We the switched the main station between 40 and 160 meters a few times, trying to make QSOs while keeping our fingers in the 160 meter pie. We finished with 160 at sunrise, but could not hear any Japanese stations, just the odd North American caller, with mostly weak to very weak signals. We quickly changed over to 40 at 0730 where we were able to work a steady stream of Japanese stations until about 0830, when the band suddenly closed. Meanwhile, the second station was working North America, Europe and Japan on 80 meters, under good conditions until 0800.”
The disruptions George spoke of were no doubt triggered by one or more of the several coronal mass ejections (CMEs) that our Sun spewed forth last week.
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.