The K7RA Solar Update
Our Sun is still quite active, but sunspot numbers are down this week, when compared with the week before. The average daily sunspot numbers were down nearly 34 points to 68.3, while the average daily solar flux declined nearly 3 points to 111.8. But geomagnetic activity was quite strong this week, with the planetary A index on April 2 at 20, and 26 on April 6. Sunspot numbers for March 31-April 6 were 76, 62, 66, 70, 83, 65 and 56, with a mean of 68.3. The 10.7 cm flux was 113.3, 108.9, 107.5, 114, 112.7, 109.2 and 117.1, with a mean of 111.8. The estimated planetary A indices were 3, 13, 20, 16, 8, 7 and 26, with a mean of 13.3. The estimated mid-latitude A indices were 2, 9, 13, 11, 6, 4, and 16, with a mean of 8.7.
The latest forecast from USAF and NOAA is for lower activity than the forecast from Wednesday, as reported in this week’s ARRL Letter. The latest from Thursday, April 7 has a solar flux of 110, 100, 95 and 100 for April 8-11, 105 on April 12-15, then 90, 100, and 115 on April 16-18 and 125 on April 19-27. The predicted planetary A index is 5, 5, 10 and 10 on April 8-11, 5 on April 12-17 and 7 on April 18-20. Geophysical Institute Prague predicts quiet conditions on April 8, quiet to unsettled April 9, unsettled to active April 10, active April 11, unsettled April 12, quiet to unsettled April 13 and back to quiet on April 14.
On April 4, NASA released a new solar cycle prediction, and they say Solar Cycle 24 may be the smallest sunspot cycle in 200 years. NOAA/SWPC Boulder has their own updated prediction, which you can see on page 14 of the Preliminary Report and Forecast for April 5. This has hardly changed from last month’s version, but notice that the predicted smoothed sunspot values for April, May and August 2011 are each slightly higher on the new one, by 1 point each. Since these smoothed values are averaged over a year, perhaps this slight increase is because of higher recent solar activity.
Glenn Wyant, VA3DX, of St Catherines, Ontario, sent in a report on some DX he recently worked: “On March 25, my good friend Garry, VE3XN, called me on the phone at about 1125. He claimed he had just finished his 5 Band WAZ with a XU7ACY (Cambodia) QSO on 80 meters CW! Although it was too late for me that day, I was there the next day and put Peter, XU7ACY, in my log for a new one on 80 What was really neat was to work Peter again on March 28 at 1133 for a new one on 12 meters! I also worked E21EJC (Thailand) on 12 meters at 1620 for another new one on 12. The following day (March 29), I again worked Kob, E21EJC, on 10 meters at 1440, as well as VU4PB on 12 CW at 0103. I had to beam at 190 degrees to copy him. I figured I was done with new band countries for awhile now, but March 30 proved me wrong. At 1437, I worked VU4PB on 10 meters CW and then again at 1558 on 10 meters SSB. Both QSOs were on the traditional path at 10 degrees. What was strange was that VU4PB was 5×7 here at one point on SSB, yet Garry -- only 142 miles west of me and using the same kind of antenna at the same height -- could not copy them at all! Sort of like 6 meter spotlight propagation.” See a picture of Glenn and his station here.
Angel Santana, WP3GW, of Trujillo Alto, Puerto Rico, wrote: “Last week I had an ‘Arabian Night,’ because between March31 and April 1 UTC over a 50 minute period, I was able to work A92GR, A41OW and 9K2OD on 20 meters, plus I heard 9Y4D work a VU3, which sounded very strong! Just 30 minutes later, I contacted the largest island of the world – Greenland, OX3KQ on 18.126 MHz. And incredibly, I got to work YB0NFL on 10 meters at 1530 (11:30 am local) on Saturday, April 2!” This was all on SSB. See an interesting photo of Angel in his station here.
Dan Eskenazi, K7SS, of Seattle notes that just before the recent improved propagation conditions, his antenna blew down in a windstorm. Now some of his more superstitious ham friends are begging him not to put it back up.
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.