The K7RA Solar Update
Another week of quiet Sun, but on Wednesday and Thursday -- August 20-21 -- a new spot seemed to be emerging, but there is no sign that it is anything other than an old Solar Cycle 23 spot. Spaceweather.com reported it with a sunspot number of 11 for August 21, but NOAA did not, reporting zero instead for Thursday. A late Thursday image suggests a spot in the northern hemisphere on the left side of the image. Sunspot numbers for August 14-20 were 0, 0, 0, 0, 0, 0 and 0 with a mean of 0. The 10.7 cm flux was 65.9, 65.3, 66.2, 66.5, 66.2, 67.3 and 65.9 with a mean of 66.2. Estimated planetary A indices were 5, 4, 5, 7, 23, 8 and 6 with a mean of 8.3. Estimated mid-latitude A indices were 4, 3, 4, 5, 15, 7 and 5 with a mean of 6.1.
On March 2, 2007, we speculated whether Solar Cycle minimum had been reached. The same issue mentioned a personal quest by JQ2UOZ to work DXCC at the solar cycle minimum running only one-half W on 17 meters and higher using dipole antennas. In an e-mail this week, he said he has reached his goal. So far he has worked 138 countries; and you can see details on his Web site.
Tony Dixon, G4CJC, of London, England, produces a weekly report on the 10 meter band -- including calls heard. Even at the bottom of the cycle, there is still propagation on 10 meters, although it tends to be sporadic-E skip, rather than the F layer propagation we see when there are more sunspots.
This week, NASA released an article with details on upcoming solar research initiatives, ranging from soon to 2015. One that is expected to launch in 2015 will place four satellites around the Sun to observe solar activity on the side facing away from Earth.
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 in The ARRL Letter. Check 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.