The K7RA Solar Update


That was a nice string of days showing a sunspot -- May 13-19 -- a whole week. Then it was gone, but a few days later on May 23, another Solar Cycle 24 sunspot emerged, this time in our Sun's southern hemisphere. But it was another of those phantom spots. This one actually emerged, and gave us a sunspot number of 13. For that one day it covered 30 10E-6 hemispheres. (10E-6, or 10 to the minus sixth power, is another way of expressing the fraction one-millionth). The next day it was gone.

The area of that spot represented .003 percent of the hemisphere of the Sun that we could see, that which was pointed toward us. Because 10E-6 is one-millionth, then 30 times that would be thirty-millionths (three hundred-thousandths), or .003 percent. During the seven days with a sunspot, May 13-19, the sunspot numbers were 12, 18, 12, 15, 13, 14 and 11. On those same dates, the sunspot area expressed in millionths of a solar hemisphere was 10, 20, 10, 20, 10, 30 and 10. See those daily numbers here.

When we see more activity, these values can be much larger. Note that the sunspot area doesn't track exactly relative to sunspot number. The largest sunspot area was on May 18 and the largest sunspot number was May 14. Thanks to Carl Luetzelschwab, K9LA, for the refresher on scientific notation and the function of E.

Sunspot numbers for May 21 through 27 were 0, 0, 13, 0, 0, 0 and 0 with a mean of 1.9. The 10.7 cm flux was 71.8, 72.1, 70.4, 69.2, 68.9, 68.1 and 66.7 with a mean of 69.6. The estimated planetary A indices were 5, 5, 4, 4, 3, 4 and 3 with a mean of 4. The estimated mid-latitude A indices were 2, 4, 3, 4, 1, 2 and 2 with a mean of 2.6.

Conditions have been quiet, with many days showing zeros for the planetary K index. The US Air Force and NOAA predict a planetary A index of 5 until June 3-5 when it goes to 12, then 8 for the following two days. Solar flux is predicted at 68 until June 5, when it goes to 70, then 71 June 6, and 72 for June 7-14. Perhaps we will see sunspots return during this period. Geophysical Institute Prague has a slightly different view for geomagnetic activity, predicting quiet conditions for May 29 to June 1, quiet to unsettled June 2-3 and active on June 4.

Conditions should be stable for the CQ World Wide WPX CW Contest this weekend. You could be a sought-after multiplier with the right prefix in that contest. Back when I was KT7H, I was one of those; K7RA, however, is not.

Days grow longer, and the summer solstice -- the longest day of the year -- is June 21. The vernal equinox was March 19; it is interesting to compare propagation projections on those dates. With minimal sunspot activity, from the center of the contiguous 48 states (near the center of Northern Kansas, about a dozen miles south of the Nebraska border between Cora and Lebanon), we can compare propagation predictions for the equinox and solstice.

To Japan, in the spring we might see a 20 meter opening in the late afternoon and evening from 2100-0400 UTC. In summer, that Japan opening would run much later, beginning around 0500 UTC with signal strength increasing dramatically, and fading out around 1700 UTC. The 80 meter opening over the same path would be much shorter duration in the summer, because it needs darkness, and the night is so short on the longest day of the year, more so in northern latitudes. We might see 80 meters open 1030-1130 UTC, but in the spring it runs from 0800-1430 UTC.

From Los Angeles to Hawaii on those dates, on 20 meters it might be easier to describe when it is least likely to be open. Openings are least likely on March 21 from 0500-1600 UTC, all night. On June 21, the least likely period for a 20 meter opening would be 0600-1530 UTC.

Thanks to Peter Laws, N5UWY of Norman, Oklahoma who points out that the NY Times article referenced in last week's bulletin was not from the 19th century, but was published May 17, 1921.

Emory Stephens wrote on May 22 that "a recent article issued by NOAA stated there are signs that the number of sunspots should increase. You indicated in your posting that is an unknown area. Is NOAA's statement science, or are they making a calculated guess?"

I believe it is a guess calculated on average past cycles, and the fact that this minimum has continued so long. So the longer it goes on, the more likely it is to increase soon, by their reasoning.

On May 22, George Thorward, N6CAS, of Happy Camp, California, wrote about 20 meter activity over the previous week. George said he hears low power mobile stations working Europe, while signals from the Pacific are coming in loud and clear at the same time. He notes that "Europe has been wide open this week," and 10 meters has been open from time to time, as well. Check out photos of the N6CAS installation here.

Dave Bennett, VE7YJ, of Aldergrove, British Columbia, wrote, "I noted the item about KH6XS working in to Europe on 15 meters and just thought I'd add that he's been heard here late evenings on that band recently, 'testing propagation.' Unfortunately, I'm not set up for CW operation, so couldn't respond to his CQ, but did note it on the DX Cluster. That band has also been open to South America, with LU stations well heard, though my pipsqueak signal doesn't seem to go the other way."

John Ragle, W1ZI, of Hadley, Massachusetts, was another who wrote right after last week's bulletin was released: "When are bands 'dead' and when are bands 'unoccupied'? Here in Western Massachusetts, I keep an eye on 15 meters by switching my PSK rig to the band and looking for traces on the waterfall around 21.070. Today, for example [May 22, 2009], around local noon, there was strong north-south activity, in the case of PS7YL and a few others, resulting in 599 signals. These signals persisted for several hours through the afternoon. The waterfall also showed many weak traces, too weak for copy, but there nonetheless. Since the PSK is pretty automated, I call CQ with 15 W and a dipole from time to time from local noon and into the afternoon, as curiosity warrants (and usually without results). I think that the MUF is quite high enough for good contacts via trans-equatorial paths, but that people are simply convinced that the band is 'dead,' and are not paying attention. Perhaps it wouldn't hurt for people who can use weak-signal (i.e. CW and other digital) modes to exercise them once in a while on apparently 'dead' bands." Thanks, John!

Red Haines, WO0W (between the two Ws are the letter O followed by the number zero), has been watching data from ionosondes (instruments that beam radio signals straight up to see the range of frequencies that bounce back). Quite a few ionosondes listed at here have been silent of late. The data of interest is in the f0f2 column, the MUF figure. Red writes: "A most interesting observation in the past week is the wild excursions of f0F2 over short periods, less than an hour. I suspect this indicates what McNamara calls 'ionospheric storms,' which create rapidly changing HF propagation, often seen as 'fading.' I refer to Radio Amateur's Guide to the Ionosphere by Leo F. McNamara. This book bridges the gap between texts and technically inadequate publications. I recommend it highly to amateur operators who wish to know more about propagation." Thanks for the tip, Red!

Pete Malvasi, W2PM, of Ramsey, New Jersey, wrote in regard to mention in recent bulletins of large aurora events disrupting the telegraph circuits of yesteryear: "I've read accounts of serious disruption to early telegraph land-lines in several period texts, including an extensive chapter in The History, Theory and Practice of the Electric Telegraph by George B Prescott. Reports of office fires and fireball display are all associated with electrical storms however and not the aurora." Pete sent a reference to an account of geomagnetic disruption to telegraph cables, which you can find here.

Pete continued: "Other accounts I've read in early texts describe operating conditions in the mid-19th century to be very similar to working present day CW with fading, static, temporary outages and such. They used a single wire in those days with a ground return, and many of the earliest lines did not use good materials for insulators, so there was a lot of leakage to ground. Perhaps the single wire circuits also made the lines more susceptible to the aurora?"

Jon Jones, N0JK, is currently using an indoor dipole on 6 meters in Lawrence, Kansas. He writes, "A multi-hop Es opening on 6 meters to Japan occurred on May 22 from the Central USA. I copied JE1BMJ on an indoor dipole. W7CNK (EM15) in Oklahoma and stations in Colorado and Texas worked a number of stations in Japan via multi-hop Es." Jon sent a list of 16 QSOs copied, mostly between US and foreign stations from 2313-2331 UTC.

And finally, this one was sent by Danny Eskenazi, K7SS, concerning an intriguing tale of a possible resurgence of interest in Morse Code, by text-message happy youth in Japan; however, this one gives a moderate-to-slightly high reading on my baloney-detector, which may be over-sensitized. Read it here and judge for yourself. Note that users can only send text messages -- not receive -- and must check their e-mail for replies, in addition to learning Morse code. Can anyone translate that Kanji text? Or is it Katakana?

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.