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The K7RA Solar Update


Thanks to Carl Luetzelschwab, K9LA, for writing last week's bulletin.

Two new sunspots appeared last week, numbered 1022 and 1023, and both were Solar Cycle 24 spots, with 1022 lasting through June 23 and 1023 until June 24. On June 24, geomagnetic indices were unsettled. Sunspot numbers for June 18-24 were 0, 0, 0, 12, 24, 12 and 14 with a mean of 8.9. The 10.7 cm flux was 68, 67, 67, 67, 68, 68 and 67 with a mean of 67.4. The estimated planetary A indices were 4, 4, 6, 7, 3, 4 and 19 with a mean of 6.7. The estimated mid-latitude A indices were 2, 1, 5, 6, 2, 5 and 16 with a mean of 5.3. This weekend is ARRL Field Day, and conditions should be stable; Planetary A index is predicted to be around five, which is quiet.

Chip Margelli, K7JA, wrote about some surprising openings last week: "Sunspots or no, there are DX opportunities even with a solar flux of 67. Both Friday and Saturday nights (US time June 19-20), the 21 MHz and 28 MHz bands were open to Japan from my location in Southern California and along much of the West Coast, around 0500-0800 UTC (that's 10 PM to at least 1 AM!) Both nights, the 15 meter CW band was crawling with loud JA signals from stations working the All Asian DX Contest and there were many loud signals on 10 meters, as well. I fear many did not think to check 10 at this hour, but it very much was open. And Saturday night I worked 54 JA stations in a nice run on 50 MHz, so perhaps those noctilucent clouds were being kind to me."

Steve Brandt, N7VS, of Portland, Oregon had a similar observation. On 10 meters CW last Friday night (at 0336 UTC Saturday), Steve worked JK1YMM in the All Asia CW Contest with S7 reports in both directions. Steve also observed sporadic E openings this week out to about 1000 miles and said other stations have reported working Japan on 10 meters this week.

In last week's bulletin, Carl mentioned the upcoming DXpedition to Glorioso in July. Now he has written a set of predictions for propagation to Glorioso from various areas, and you can see it here. Just click on the "Glorioso in July 2009" link.

I received some interesting mail from Red Haines, WO0W, of La Crescent, Minnesota. I did a search for past e-mails from him and came across an unread mail from December, 2007. Just to review and clarify, an ionosonde is a tool for measuring the critical frequency (f0F2) for the area just above. It sweeps an RF signal, beaming straight up, and looks for reflections.

Some quotes from Red occupy the next few paragraphs"

"Though we use the sunspot number and the solar flux index to assess propagation expectations, there is only an indirect connection between these indices and propagation. Neither sunspots nor the radiation measured by the solar flux index directly increase or decrease the levels of ionization in the ionosphere. All three are determined, somewhat independently, by physical processes on or in the Sun.

"Sunspots and the solar flux are caused by solar conditions that are often associated to a limited degree with high energy radiation that reaches Earth and ionizes molecules in the atmosphere. Only the energetic radiation (UV, X-ray and Gamma rays) from the Sun or other sources ionize those molecules. The solar flux radiation is not energetic enough. The sunspots are only a visual phenomena associated with solar events, including radiation.

"It often happens that no solar radiation associated with a sunspot reaches Earth. In past years, we didn't have any better predictors of propagation than the sunspot number and the solar flux index. They remain useful, but we must recognize their limitations. In fact, propagation correlates very poorly with them. Smoothed sunspot numbers are useful to study the solar activity cycle. A smoothed sunspot number doesn't predict the next day's propagation or even the next cycle's timing or magnitude. In fact, the smoothed SSN cannot be calculated until 6 months have passed. The daily SSN is just about meaningless to propagation.

"Today, we have better indicators of propagation potential. Hams may view near real time measures of X-ray radiation from the GOES satellites. The various propagation beacons are very useful to assess current propagation. A source of near real time ionospheric conditions, including the various critical frequencies, may be accessed here. This index links to the worldwide system of ionosondes to report measured values on short time intervals, typically near 15 minutes. The shortcoming is the relatively small number of ionosondes, which requires interpolation to estimate the MUF for a propagation path, as well as educated guesses regarding details of the path.

"The Australian IPS Radio and Space Services offer several maps that attempt to depict interpolated propagation conditions, based on ionosonde measurements."

In a message from June 15, Red wrote:

"Perhaps you already noted the large increase in f0F2 reported by the ionosonde at Boulder. Rapid fluctuations beginning after 1200 UTC June 14 reached high values as high as 14 MHz. The fluctuations were prominent.

"By the time I noticed and turned to the DX beacons, values were back to usual and the RTTY signals interfered too much to discern much on 14.1 MHz. By that time, about 2300 UTC, I didn't hear any beacons on 21.150 MHz. I sure wish the RTTY operators were more aware of the value of those beacons, to themselves as much as to others.

"Signals on 80 meters at 2330 UTC, from net stations that I work every day at that time, were about 20 dB lower than has been typical during recent weeks. These were stations within MN. Perhaps D-layer absorption was increased. On a region net at 0045 UTC, also 80 meters, signals were a bit lower, but were back to normal at 0230z, as were the MN net signals at 0250 UTC.

"I haven't found the cause of the ionospheric fluctuations. I examined the graph of X-ray flux and it was 'flatlined.' I found no evidence of any major particulate density reaching Earth from the Sun.

"Of more general interest, the Millstone station resumed posting ionosonde readings for a couple weeks, though not continuous, but has discontinued the postings. I suspect that the IPS maps are relatively inaccurate for lack of ionosonde data. I note considerable disparity between those maps in the US and the Boulder data. I began recording the Boulder data to study that in greater detail."

And finally on June 23, this from Red:

"You probably noted the appearance in the southern hemisphere of two sunspot groups with a SSN of 24 on June 22. Did you also notice a burst of low energy X-ray on June 22 and the large excursions of f0F2 at about 1400 UTC, 2300 UTC (June 22 UTC) and 0800 UTC (June 23 UTC)? The f0F2 reported by Boulder reached 11 MHz at 0800 UTC June 23 and displays a series of high and low excursions. The other ionosondes in the USA continue to report no data. IPS maps are not tracking these excursions, probably because data needed for the map model is lacking".

We also had several reports on grayline propagation recently. Here are two of them:

On June 12, Roland Spoon, AH6RR, of Kailua Kona, on the Big Island of Hawaii, wrote: "The past two weeks have just been hopping on 20 meters here in Hawaii. I have been making contacts almost worldwide with the exception of South America. Evening grayline is open to Africa, Asia, Middle East, Europe and Oceania. With openings to Europe until 10+ PM local time, signals are between S5 and 20 over 9. Morning grayline favors the Middle East and Africa, with some light but workable Europe. Stu, KH7DX, reports that between midnight local and 4 AM good openings to the Indian Ocean and Africa. We have been having a blast working the pile-ups."

Another grayline report came from Brian Webb, KD6NRP, of Ventura County, California. On Monday at 0350 UTC (Sunday night local time), Brian was on PSK31 and "I called CQ on 14070 kHz with no takers. Just as I was reaching up to close my software, someone answered. The other station had a funny call and I suspected my system hadn't decoded the signal correctly. But the other station repeated his call and I was receiving it correctly. I then proceeded to have a brief, but exciting QSO with Nigel, E51SC, in Rarotonga in the South Cook Islands. Despite the low solar flux and my compromise antenna, the contact apparently was made possible due to grayline propagation. A check of my propagation software confirmed that at 0400 UTC, the terminator (day/night line) ran through southern California to the South Cook Islands."

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.



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